diff --git a/src/cmd/compile/internal/gc/abiutils_test.go b/src/cmd/compile/internal/gc/abiutils_test.go
index 5a88332de8..fe9a838688 100644
--- a/src/cmd/compile/internal/gc/abiutils_test.go
+++ b/src/cmd/compile/internal/gc/abiutils_test.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"bufio"
 	"cmd/compile/internal/base"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/obj/x86"
@@ -42,7 +43,7 @@ func TestMain(m *testing.M) {
 	types.TypeLinkSym = func(t *types.Type) *obj.LSym {
 		return typenamesym(t).Linksym()
 	}
-	TypecheckInit()
+	typecheck.Init()
 	os.Exit(m.Run())
 }
 
diff --git a/src/cmd/compile/internal/gc/abiutilsaux_test.go b/src/cmd/compile/internal/gc/abiutilsaux_test.go
index 8585ab9a30..e6590beac0 100644
--- a/src/cmd/compile/internal/gc/abiutilsaux_test.go
+++ b/src/cmd/compile/internal/gc/abiutilsaux_test.go
@@ -9,6 +9,7 @@ package gc
 
 import (
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
 	"fmt"
@@ -19,7 +20,7 @@ import (
 
 func mkParamResultField(t *types.Type, s *types.Sym, which ir.Class) *types.Field {
 	field := types.NewField(src.NoXPos, s, t)
-	n := NewName(s)
+	n := typecheck.NewName(s)
 	n.Class_ = which
 	field.Nname = n
 	n.SetType(t)
@@ -42,7 +43,7 @@ func mkstruct(fieldtypes []*types.Type) *types.Type {
 }
 
 func mkFuncType(rcvr *types.Type, ins []*types.Type, outs []*types.Type) *types.Type {
-	q := lookup("?")
+	q := typecheck.Lookup("?")
 	inf := []*types.Field{}
 	for _, it := range ins {
 		inf = append(inf, mkParamResultField(it, q, ir.PPARAM))
diff --git a/src/cmd/compile/internal/gc/alg.go b/src/cmd/compile/internal/gc/alg.go
index dab27b4929..b0d46eab2f 100644
--- a/src/cmd/compile/internal/gc/alg.go
+++ b/src/cmd/compile/internal/gc/alg.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"fmt"
@@ -106,7 +107,7 @@ func genhash(t *types.Type) *obj.LSym {
 			return closure
 		}
 		if memhashvarlen == nil {
-			memhashvarlen = sysfunc("memhash_varlen")
+			memhashvarlen = typecheck.LookupRuntimeFunc("memhash_varlen")
 		}
 		ot := 0
 		ot = dsymptr(closure, ot, memhashvarlen, 0)
@@ -143,17 +144,17 @@ func genhash(t *types.Type) *obj.LSym {
 	}
 
 	base.Pos = base.AutogeneratedPos // less confusing than end of input
-	dclcontext = ir.PEXTERN
+	typecheck.DeclContext = ir.PEXTERN
 
 	// func sym(p *T, h uintptr) uintptr
 	args := []*ir.Field{
-		ir.NewField(base.Pos, lookup("p"), nil, types.NewPtr(t)),
-		ir.NewField(base.Pos, lookup("h"), nil, types.Types[types.TUINTPTR]),
+		ir.NewField(base.Pos, typecheck.Lookup("p"), nil, types.NewPtr(t)),
+		ir.NewField(base.Pos, typecheck.Lookup("h"), nil, types.Types[types.TUINTPTR]),
 	}
 	results := []*ir.Field{ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR])}
 	tfn := ir.NewFuncType(base.Pos, nil, args, results)
 
-	fn := dclfunc(sym, tfn)
+	fn := typecheck.DeclFunc(sym, tfn)
 	np := ir.AsNode(tfn.Type().Params().Field(0).Nname)
 	nh := ir.AsNode(tfn.Type().Params().Field(1).Nname)
 
@@ -165,7 +166,7 @@ func genhash(t *types.Type) *obj.LSym {
 		hashel := hashfor(t.Elem())
 
 		// for i := 0; i < nelem; i++
-		ni := temp(types.Types[types.TINT])
+		ni := typecheck.Temp(types.Types[types.TINT])
 		init := ir.NewAssignStmt(base.Pos, ni, ir.NewInt(0))
 		cond := ir.NewBinaryExpr(base.Pos, ir.OLT, ni, ir.NewInt(t.NumElem()))
 		post := ir.NewAssignStmt(base.Pos, ni, ir.NewBinaryExpr(base.Pos, ir.OADD, ni, ir.NewInt(1)))
@@ -177,7 +178,7 @@ func genhash(t *types.Type) *obj.LSym {
 
 		nx := ir.NewIndexExpr(base.Pos, np, ni)
 		nx.SetBounded(true)
-		na := nodAddr(nx)
+		na := typecheck.NodAddr(nx)
 		call.Args.Append(na)
 		call.Args.Append(nh)
 		loop.Body.Append(ir.NewAssignStmt(base.Pos, nh, call))
@@ -201,7 +202,7 @@ func genhash(t *types.Type) *obj.LSym {
 				hashel := hashfor(f.Type)
 				call := ir.NewCallExpr(base.Pos, ir.OCALL, hashel, nil)
 				nx := ir.NewSelectorExpr(base.Pos, ir.OXDOT, np, f.Sym) // TODO: fields from other packages?
-				na := nodAddr(nx)
+				na := typecheck.NodAddr(nx)
 				call.Args.Append(na)
 				call.Args.Append(nh)
 				fn.Body.Append(ir.NewAssignStmt(base.Pos, nh, call))
@@ -216,7 +217,7 @@ func genhash(t *types.Type) *obj.LSym {
 			hashel := hashmem(f.Type)
 			call := ir.NewCallExpr(base.Pos, ir.OCALL, hashel, nil)
 			nx := ir.NewSelectorExpr(base.Pos, ir.OXDOT, np, f.Sym) // TODO: fields from other packages?
-			na := nodAddr(nx)
+			na := typecheck.NodAddr(nx)
 			call.Args.Append(na)
 			call.Args.Append(nh)
 			call.Args.Append(ir.NewInt(size))
@@ -234,13 +235,13 @@ func genhash(t *types.Type) *obj.LSym {
 		ir.DumpList("genhash body", fn.Body)
 	}
 
-	funcbody()
+	typecheck.FinishFuncBody()
 
 	fn.SetDupok(true)
-	typecheckFunc(fn)
+	typecheck.Func(fn)
 
 	ir.CurFunc = fn
-	typecheckslice(fn.Body, ctxStmt)
+	typecheck.Stmts(fn.Body)
 	ir.CurFunc = nil
 
 	if base.Debug.DclStack != 0 {
@@ -248,7 +249,7 @@ func genhash(t *types.Type) *obj.LSym {
 	}
 
 	fn.SetNilCheckDisabled(true)
-	Target.Decls = append(Target.Decls, fn)
+	typecheck.Target.Decls = append(typecheck.Target.Decls, fn)
 
 	// Build closure. It doesn't close over any variables, so
 	// it contains just the function pointer.
@@ -284,9 +285,9 @@ func hashfor(t *types.Type) ir.Node {
 		sym = typesymprefix(".hash", t)
 	}
 
-	n := NewName(sym)
+	n := typecheck.NewName(sym)
 	ir.MarkFunc(n)
-	n.SetType(functype(nil, []*ir.Field{
+	n.SetType(typecheck.NewFuncType(nil, []*ir.Field{
 		ir.NewField(base.Pos, nil, nil, types.NewPtr(t)),
 		ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR]),
 	}, []*ir.Field{
@@ -298,9 +299,9 @@ func hashfor(t *types.Type) ir.Node {
 // sysClosure returns a closure which will call the
 // given runtime function (with no closed-over variables).
 func sysClosure(name string) *obj.LSym {
-	s := sysvar(name + "·f")
+	s := typecheck.LookupRuntimeVar(name + "·f")
 	if len(s.P) == 0 {
-		f := sysfunc(name)
+		f := typecheck.LookupRuntimeFunc(name)
 		dsymptr(s, 0, f, 0)
 		ggloblsym(s, int32(types.PtrSize), obj.DUPOK|obj.RODATA)
 	}
@@ -349,7 +350,7 @@ func geneq(t *types.Type) *obj.LSym {
 			return closure
 		}
 		if memequalvarlen == nil {
-			memequalvarlen = sysvar("memequal_varlen") // asm func
+			memequalvarlen = typecheck.LookupRuntimeVar("memequal_varlen") // asm func
 		}
 		ot := 0
 		ot = dsymptr(closure, ot, memequalvarlen, 0)
@@ -372,20 +373,20 @@ func geneq(t *types.Type) *obj.LSym {
 	// Autogenerate code for equality of structs and arrays.
 
 	base.Pos = base.AutogeneratedPos // less confusing than end of input
-	dclcontext = ir.PEXTERN
+	typecheck.DeclContext = ir.PEXTERN
 
 	// func sym(p, q *T) bool
 	tfn := ir.NewFuncType(base.Pos, nil,
-		[]*ir.Field{ir.NewField(base.Pos, lookup("p"), nil, types.NewPtr(t)), ir.NewField(base.Pos, lookup("q"), nil, types.NewPtr(t))},
-		[]*ir.Field{ir.NewField(base.Pos, lookup("r"), nil, types.Types[types.TBOOL])})
+		[]*ir.Field{ir.NewField(base.Pos, typecheck.Lookup("p"), nil, types.NewPtr(t)), ir.NewField(base.Pos, typecheck.Lookup("q"), nil, types.NewPtr(t))},
+		[]*ir.Field{ir.NewField(base.Pos, typecheck.Lookup("r"), nil, types.Types[types.TBOOL])})
 
-	fn := dclfunc(sym, tfn)
+	fn := typecheck.DeclFunc(sym, tfn)
 	np := ir.AsNode(tfn.Type().Params().Field(0).Nname)
 	nq := ir.AsNode(tfn.Type().Params().Field(1).Nname)
 	nr := ir.AsNode(tfn.Type().Results().Field(0).Nname)
 
 	// Label to jump to if an equality test fails.
-	neq := autolabel(".neq")
+	neq := typecheck.AutoLabel(".neq")
 
 	// We reach here only for types that have equality but
 	// cannot be handled by the standard algorithms,
@@ -450,7 +451,7 @@ func geneq(t *types.Type) *obj.LSym {
 			} else {
 				// Generate a for loop.
 				// for i := 0; i < nelem; i++
-				i := temp(types.Types[types.TINT])
+				i := typecheck.Temp(types.Types[types.TINT])
 				init := ir.NewAssignStmt(base.Pos, i, ir.NewInt(0))
 				cond := ir.NewBinaryExpr(base.Pos, ir.OLT, i, ir.NewInt(nelem))
 				post := ir.NewAssignStmt(base.Pos, i, ir.NewBinaryExpr(base.Pos, ir.OADD, i, ir.NewInt(1)))
@@ -586,7 +587,7 @@ func geneq(t *types.Type) *obj.LSym {
 
 	// ret:
 	//   return
-	ret := autolabel(".ret")
+	ret := typecheck.AutoLabel(".ret")
 	fn.Body.Append(ir.NewLabelStmt(base.Pos, ret))
 	fn.Body.Append(ir.NewReturnStmt(base.Pos, nil))
 
@@ -610,13 +611,13 @@ func geneq(t *types.Type) *obj.LSym {
 		ir.DumpList("geneq body", fn.Body)
 	}
 
-	funcbody()
+	typecheck.FinishFuncBody()
 
 	fn.SetDupok(true)
-	typecheckFunc(fn)
+	typecheck.Func(fn)
 
 	ir.CurFunc = fn
-	typecheckslice(fn.Body, ctxStmt)
+	typecheck.Stmts(fn.Body)
 	ir.CurFunc = nil
 
 	if base.Debug.DclStack != 0 {
@@ -628,7 +629,7 @@ func geneq(t *types.Type) *obj.LSym {
 	// neither of which can be nil, and our comparisons
 	// are shallow.
 	fn.SetNilCheckDisabled(true)
-	Target.Decls = append(Target.Decls, fn)
+	typecheck.Target.Decls = append(typecheck.Target.Decls, fn)
 
 	// Generate a closure which points at the function we just generated.
 	dsymptr(closure, 0, sym.Linksym(), 0)
@@ -660,20 +661,20 @@ func eqfield(p ir.Node, q ir.Node, field *types.Sym) ir.Node {
 // which can be used to construct string equality comparison.
 // eqlen must be evaluated before eqmem, and shortcircuiting is required.
 func eqstring(s, t ir.Node) (eqlen *ir.BinaryExpr, eqmem *ir.CallExpr) {
-	s = conv(s, types.Types[types.TSTRING])
-	t = conv(t, types.Types[types.TSTRING])
+	s = typecheck.Conv(s, types.Types[types.TSTRING])
+	t = typecheck.Conv(t, types.Types[types.TSTRING])
 	sptr := ir.NewUnaryExpr(base.Pos, ir.OSPTR, s)
 	tptr := ir.NewUnaryExpr(base.Pos, ir.OSPTR, t)
-	slen := conv(ir.NewUnaryExpr(base.Pos, ir.OLEN, s), types.Types[types.TUINTPTR])
-	tlen := conv(ir.NewUnaryExpr(base.Pos, ir.OLEN, t), types.Types[types.TUINTPTR])
+	slen := typecheck.Conv(ir.NewUnaryExpr(base.Pos, ir.OLEN, s), types.Types[types.TUINTPTR])
+	tlen := typecheck.Conv(ir.NewUnaryExpr(base.Pos, ir.OLEN, t), types.Types[types.TUINTPTR])
 
-	fn := syslook("memequal")
-	fn = substArgTypes(fn, types.Types[types.TUINT8], types.Types[types.TUINT8])
+	fn := typecheck.LookupRuntime("memequal")
+	fn = typecheck.SubstArgTypes(fn, types.Types[types.TUINT8], types.Types[types.TUINT8])
 	call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, []ir.Node{sptr, tptr, ir.Copy(slen)})
-	TypecheckCall(call)
+	typecheck.Call(call)
 
 	cmp := ir.NewBinaryExpr(base.Pos, ir.OEQ, slen, tlen)
-	cmp = typecheck(cmp, ctxExpr).(*ir.BinaryExpr)
+	cmp = typecheck.Expr(cmp).(*ir.BinaryExpr)
 	cmp.SetType(types.Types[types.TBOOL])
 	return cmp, call
 }
@@ -692,9 +693,9 @@ func eqinterface(s, t ir.Node) (eqtab *ir.BinaryExpr, eqdata *ir.CallExpr) {
 	// func efaceeq(typ *uintptr, x, y unsafe.Pointer) (ret bool)
 	var fn ir.Node
 	if s.Type().IsEmptyInterface() {
-		fn = syslook("efaceeq")
+		fn = typecheck.LookupRuntime("efaceeq")
 	} else {
-		fn = syslook("ifaceeq")
+		fn = typecheck.LookupRuntime("ifaceeq")
 	}
 
 	stab := ir.NewUnaryExpr(base.Pos, ir.OITAB, s)
@@ -707,10 +708,10 @@ func eqinterface(s, t ir.Node) (eqtab *ir.BinaryExpr, eqdata *ir.CallExpr) {
 	tdata.SetTypecheck(1)
 
 	call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, []ir.Node{stab, sdata, tdata})
-	TypecheckCall(call)
+	typecheck.Call(call)
 
 	cmp := ir.NewBinaryExpr(base.Pos, ir.OEQ, stab, ttab)
-	cmp = typecheck(cmp, ctxExpr).(*ir.BinaryExpr)
+	cmp = typecheck.Expr(cmp).(*ir.BinaryExpr)
 	cmp.SetType(types.Types[types.TBOOL])
 	return cmp, call
 }
@@ -718,8 +719,8 @@ func eqinterface(s, t ir.Node) (eqtab *ir.BinaryExpr, eqdata *ir.CallExpr) {
 // eqmem returns the node
 // 	memequal(&p.field, &q.field [, size])
 func eqmem(p ir.Node, q ir.Node, field *types.Sym, size int64) ir.Node {
-	nx := typecheck(nodAddr(ir.NewSelectorExpr(base.Pos, ir.OXDOT, p, field)), ctxExpr)
-	ny := typecheck(nodAddr(ir.NewSelectorExpr(base.Pos, ir.OXDOT, q, field)), ctxExpr)
+	nx := typecheck.Expr(typecheck.NodAddr(ir.NewSelectorExpr(base.Pos, ir.OXDOT, p, field)))
+	ny := typecheck.Expr(typecheck.NodAddr(ir.NewSelectorExpr(base.Pos, ir.OXDOT, q, field)))
 
 	fn, needsize := eqmemfunc(size, nx.Type().Elem())
 	call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
@@ -735,14 +736,14 @@ func eqmem(p ir.Node, q ir.Node, field *types.Sym, size int64) ir.Node {
 func eqmemfunc(size int64, t *types.Type) (fn *ir.Name, needsize bool) {
 	switch size {
 	default:
-		fn = syslook("memequal")
+		fn = typecheck.LookupRuntime("memequal")
 		needsize = true
 	case 1, 2, 4, 8, 16:
 		buf := fmt.Sprintf("memequal%d", int(size)*8)
-		fn = syslook(buf)
+		fn = typecheck.LookupRuntime(buf)
 	}
 
-	fn = substArgTypes(fn, t, t)
+	fn = typecheck.SubstArgTypes(fn, t, t)
 	return fn, needsize
 }
 
diff --git a/src/cmd/compile/internal/gc/bexport.go b/src/cmd/compile/internal/gc/bexport.go
deleted file mode 100644
index 3c377d8ba3..0000000000
--- a/src/cmd/compile/internal/gc/bexport.go
+++ /dev/null
@@ -1,185 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package gc
-
-import (
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/types"
-)
-
-type exporter struct {
-	marked map[*types.Type]bool // types already seen by markType
-}
-
-// markObject visits a reachable object.
-func (p *exporter) markObject(n ir.Node) {
-	if n.Op() == ir.ONAME {
-		n := n.(*ir.Name)
-		if n.Class_ == ir.PFUNC {
-			inlFlood(n, exportsym)
-		}
-	}
-
-	p.markType(n.Type())
-}
-
-// markType recursively visits types reachable from t to identify
-// functions whose inline bodies may be needed.
-func (p *exporter) markType(t *types.Type) {
-	if p.marked[t] {
-		return
-	}
-	p.marked[t] = true
-
-	// If this is a named type, mark all of its associated
-	// methods. Skip interface types because t.Methods contains
-	// only their unexpanded method set (i.e., exclusive of
-	// interface embeddings), and the switch statement below
-	// handles their full method set.
-	if t.Sym() != nil && t.Kind() != types.TINTER {
-		for _, m := range t.Methods().Slice() {
-			if types.IsExported(m.Sym.Name) {
-				p.markObject(ir.AsNode(m.Nname))
-			}
-		}
-	}
-
-	// Recursively mark any types that can be produced given a
-	// value of type t: dereferencing a pointer; indexing or
-	// iterating over an array, slice, or map; receiving from a
-	// channel; accessing a struct field or interface method; or
-	// calling a function.
-	//
-	// Notably, we don't mark function parameter types, because
-	// the user already needs some way to construct values of
-	// those types.
-	switch t.Kind() {
-	case types.TPTR, types.TARRAY, types.TSLICE:
-		p.markType(t.Elem())
-
-	case types.TCHAN:
-		if t.ChanDir().CanRecv() {
-			p.markType(t.Elem())
-		}
-
-	case types.TMAP:
-		p.markType(t.Key())
-		p.markType(t.Elem())
-
-	case types.TSTRUCT:
-		for _, f := range t.FieldSlice() {
-			if types.IsExported(f.Sym.Name) || f.Embedded != 0 {
-				p.markType(f.Type)
-			}
-		}
-
-	case types.TFUNC:
-		for _, f := range t.Results().FieldSlice() {
-			p.markType(f.Type)
-		}
-
-	case types.TINTER:
-		for _, f := range t.FieldSlice() {
-			if types.IsExported(f.Sym.Name) {
-				p.markType(f.Type)
-			}
-		}
-	}
-}
-
-// ----------------------------------------------------------------------------
-// Export format
-
-// Tags. Must be < 0.
-const (
-	// Objects
-	packageTag = -(iota + 1)
-	constTag
-	typeTag
-	varTag
-	funcTag
-	endTag
-
-	// Types
-	namedTag
-	arrayTag
-	sliceTag
-	dddTag
-	structTag
-	pointerTag
-	signatureTag
-	interfaceTag
-	mapTag
-	chanTag
-
-	// Values
-	falseTag
-	trueTag
-	int64Tag
-	floatTag
-	fractionTag // not used by gc
-	complexTag
-	stringTag
-	nilTag
-	unknownTag // not used by gc (only appears in packages with errors)
-
-	// Type aliases
-	aliasTag
-)
-
-var predecl []*types.Type // initialized lazily
-
-func predeclared() []*types.Type {
-	if predecl == nil {
-		// initialize lazily to be sure that all
-		// elements have been initialized before
-		predecl = []*types.Type{
-			// basic types
-			types.Types[types.TBOOL],
-			types.Types[types.TINT],
-			types.Types[types.TINT8],
-			types.Types[types.TINT16],
-			types.Types[types.TINT32],
-			types.Types[types.TINT64],
-			types.Types[types.TUINT],
-			types.Types[types.TUINT8],
-			types.Types[types.TUINT16],
-			types.Types[types.TUINT32],
-			types.Types[types.TUINT64],
-			types.Types[types.TUINTPTR],
-			types.Types[types.TFLOAT32],
-			types.Types[types.TFLOAT64],
-			types.Types[types.TCOMPLEX64],
-			types.Types[types.TCOMPLEX128],
-			types.Types[types.TSTRING],
-
-			// basic type aliases
-			types.ByteType,
-			types.RuneType,
-
-			// error
-			types.ErrorType,
-
-			// untyped types
-			types.UntypedBool,
-			types.UntypedInt,
-			types.UntypedRune,
-			types.UntypedFloat,
-			types.UntypedComplex,
-			types.UntypedString,
-			types.Types[types.TNIL],
-
-			// package unsafe
-			types.Types[types.TUNSAFEPTR],
-
-			// invalid type (package contains errors)
-			types.Types[types.Txxx],
-
-			// any type, for builtin export data
-			types.Types[types.TANY],
-		}
-	}
-	return predecl
-}
diff --git a/src/cmd/compile/internal/gc/builtin.go b/src/cmd/compile/internal/gc/builtin.go
deleted file mode 100644
index 12c70fb6d4..0000000000
--- a/src/cmd/compile/internal/gc/builtin.go
+++ /dev/null
@@ -1,344 +0,0 @@
-// Code generated by mkbuiltin.go. DO NOT EDIT.
-
-package gc
-
-import (
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/types"
-)
-
-var runtimeDecls = [...]struct {
-	name string
-	tag  int
-	typ  int
-}{
-	{"newobject", funcTag, 4},
-	{"mallocgc", funcTag, 8},
-	{"panicdivide", funcTag, 9},
-	{"panicshift", funcTag, 9},
-	{"panicmakeslicelen", funcTag, 9},
-	{"panicmakeslicecap", funcTag, 9},
-	{"throwinit", funcTag, 9},
-	{"panicwrap", funcTag, 9},
-	{"gopanic", funcTag, 11},
-	{"gorecover", funcTag, 14},
-	{"goschedguarded", funcTag, 9},
-	{"goPanicIndex", funcTag, 16},
-	{"goPanicIndexU", funcTag, 18},
-	{"goPanicSliceAlen", funcTag, 16},
-	{"goPanicSliceAlenU", funcTag, 18},
-	{"goPanicSliceAcap", funcTag, 16},
-	{"goPanicSliceAcapU", funcTag, 18},
-	{"goPanicSliceB", funcTag, 16},
-	{"goPanicSliceBU", funcTag, 18},
-	{"goPanicSlice3Alen", funcTag, 16},
-	{"goPanicSlice3AlenU", funcTag, 18},
-	{"goPanicSlice3Acap", funcTag, 16},
-	{"goPanicSlice3AcapU", funcTag, 18},
-	{"goPanicSlice3B", funcTag, 16},
-	{"goPanicSlice3BU", funcTag, 18},
-	{"goPanicSlice3C", funcTag, 16},
-	{"goPanicSlice3CU", funcTag, 18},
-	{"printbool", funcTag, 19},
-	{"printfloat", funcTag, 21},
-	{"printint", funcTag, 23},
-	{"printhex", funcTag, 25},
-	{"printuint", funcTag, 25},
-	{"printcomplex", funcTag, 27},
-	{"printstring", funcTag, 29},
-	{"printpointer", funcTag, 30},
-	{"printuintptr", funcTag, 31},
-	{"printiface", funcTag, 30},
-	{"printeface", funcTag, 30},
-	{"printslice", funcTag, 30},
-	{"printnl", funcTag, 9},
-	{"printsp", funcTag, 9},
-	{"printlock", funcTag, 9},
-	{"printunlock", funcTag, 9},
-	{"concatstring2", funcTag, 34},
-	{"concatstring3", funcTag, 35},
-	{"concatstring4", funcTag, 36},
-	{"concatstring5", funcTag, 37},
-	{"concatstrings", funcTag, 39},
-	{"cmpstring", funcTag, 40},
-	{"intstring", funcTag, 43},
-	{"slicebytetostring", funcTag, 44},
-	{"slicebytetostringtmp", funcTag, 45},
-	{"slicerunetostring", funcTag, 48},
-	{"stringtoslicebyte", funcTag, 50},
-	{"stringtoslicerune", funcTag, 53},
-	{"slicecopy", funcTag, 54},
-	{"decoderune", funcTag, 55},
-	{"countrunes", funcTag, 56},
-	{"convI2I", funcTag, 57},
-	{"convT16", funcTag, 58},
-	{"convT32", funcTag, 58},
-	{"convT64", funcTag, 58},
-	{"convTstring", funcTag, 58},
-	{"convTslice", funcTag, 58},
-	{"convT2E", funcTag, 59},
-	{"convT2Enoptr", funcTag, 59},
-	{"convT2I", funcTag, 59},
-	{"convT2Inoptr", funcTag, 59},
-	{"assertE2I", funcTag, 57},
-	{"assertE2I2", funcTag, 60},
-	{"assertI2I", funcTag, 57},
-	{"assertI2I2", funcTag, 60},
-	{"panicdottypeE", funcTag, 61},
-	{"panicdottypeI", funcTag, 61},
-	{"panicnildottype", funcTag, 62},
-	{"ifaceeq", funcTag, 64},
-	{"efaceeq", funcTag, 64},
-	{"fastrand", funcTag, 66},
-	{"makemap64", funcTag, 68},
-	{"makemap", funcTag, 69},
-	{"makemap_small", funcTag, 70},
-	{"mapaccess1", funcTag, 71},
-	{"mapaccess1_fast32", funcTag, 72},
-	{"mapaccess1_fast64", funcTag, 72},
-	{"mapaccess1_faststr", funcTag, 72},
-	{"mapaccess1_fat", funcTag, 73},
-	{"mapaccess2", funcTag, 74},
-	{"mapaccess2_fast32", funcTag, 75},
-	{"mapaccess2_fast64", funcTag, 75},
-	{"mapaccess2_faststr", funcTag, 75},
-	{"mapaccess2_fat", funcTag, 76},
-	{"mapassign", funcTag, 71},
-	{"mapassign_fast32", funcTag, 72},
-	{"mapassign_fast32ptr", funcTag, 72},
-	{"mapassign_fast64", funcTag, 72},
-	{"mapassign_fast64ptr", funcTag, 72},
-	{"mapassign_faststr", funcTag, 72},
-	{"mapiterinit", funcTag, 77},
-	{"mapdelete", funcTag, 77},
-	{"mapdelete_fast32", funcTag, 78},
-	{"mapdelete_fast64", funcTag, 78},
-	{"mapdelete_faststr", funcTag, 78},
-	{"mapiternext", funcTag, 79},
-	{"mapclear", funcTag, 80},
-	{"makechan64", funcTag, 82},
-	{"makechan", funcTag, 83},
-	{"chanrecv1", funcTag, 85},
-	{"chanrecv2", funcTag, 86},
-	{"chansend1", funcTag, 88},
-	{"closechan", funcTag, 30},
-	{"writeBarrier", varTag, 90},
-	{"typedmemmove", funcTag, 91},
-	{"typedmemclr", funcTag, 92},
-	{"typedslicecopy", funcTag, 93},
-	{"selectnbsend", funcTag, 94},
-	{"selectnbrecv", funcTag, 95},
-	{"selectnbrecv2", funcTag, 97},
-	{"selectsetpc", funcTag, 98},
-	{"selectgo", funcTag, 99},
-	{"block", funcTag, 9},
-	{"makeslice", funcTag, 100},
-	{"makeslice64", funcTag, 101},
-	{"makeslicecopy", funcTag, 102},
-	{"growslice", funcTag, 104},
-	{"memmove", funcTag, 105},
-	{"memclrNoHeapPointers", funcTag, 106},
-	{"memclrHasPointers", funcTag, 106},
-	{"memequal", funcTag, 107},
-	{"memequal0", funcTag, 108},
-	{"memequal8", funcTag, 108},
-	{"memequal16", funcTag, 108},
-	{"memequal32", funcTag, 108},
-	{"memequal64", funcTag, 108},
-	{"memequal128", funcTag, 108},
-	{"f32equal", funcTag, 109},
-	{"f64equal", funcTag, 109},
-	{"c64equal", funcTag, 109},
-	{"c128equal", funcTag, 109},
-	{"strequal", funcTag, 109},
-	{"interequal", funcTag, 109},
-	{"nilinterequal", funcTag, 109},
-	{"memhash", funcTag, 110},
-	{"memhash0", funcTag, 111},
-	{"memhash8", funcTag, 111},
-	{"memhash16", funcTag, 111},
-	{"memhash32", funcTag, 111},
-	{"memhash64", funcTag, 111},
-	{"memhash128", funcTag, 111},
-	{"f32hash", funcTag, 111},
-	{"f64hash", funcTag, 111},
-	{"c64hash", funcTag, 111},
-	{"c128hash", funcTag, 111},
-	{"strhash", funcTag, 111},
-	{"interhash", funcTag, 111},
-	{"nilinterhash", funcTag, 111},
-	{"int64div", funcTag, 112},
-	{"uint64div", funcTag, 113},
-	{"int64mod", funcTag, 112},
-	{"uint64mod", funcTag, 113},
-	{"float64toint64", funcTag, 114},
-	{"float64touint64", funcTag, 115},
-	{"float64touint32", funcTag, 116},
-	{"int64tofloat64", funcTag, 117},
-	{"uint64tofloat64", funcTag, 118},
-	{"uint32tofloat64", funcTag, 119},
-	{"complex128div", funcTag, 120},
-	{"racefuncenter", funcTag, 31},
-	{"racefuncenterfp", funcTag, 9},
-	{"racefuncexit", funcTag, 9},
-	{"raceread", funcTag, 31},
-	{"racewrite", funcTag, 31},
-	{"racereadrange", funcTag, 121},
-	{"racewriterange", funcTag, 121},
-	{"msanread", funcTag, 121},
-	{"msanwrite", funcTag, 121},
-	{"msanmove", funcTag, 122},
-	{"checkptrAlignment", funcTag, 123},
-	{"checkptrArithmetic", funcTag, 125},
-	{"libfuzzerTraceCmp1", funcTag, 127},
-	{"libfuzzerTraceCmp2", funcTag, 129},
-	{"libfuzzerTraceCmp4", funcTag, 130},
-	{"libfuzzerTraceCmp8", funcTag, 131},
-	{"libfuzzerTraceConstCmp1", funcTag, 127},
-	{"libfuzzerTraceConstCmp2", funcTag, 129},
-	{"libfuzzerTraceConstCmp4", funcTag, 130},
-	{"libfuzzerTraceConstCmp8", funcTag, 131},
-	{"x86HasPOPCNT", varTag, 6},
-	{"x86HasSSE41", varTag, 6},
-	{"x86HasFMA", varTag, 6},
-	{"armHasVFPv4", varTag, 6},
-	{"arm64HasATOMICS", varTag, 6},
-}
-
-func runtimeTypes() []*types.Type {
-	var typs [132]*types.Type
-	typs[0] = types.ByteType
-	typs[1] = types.NewPtr(typs[0])
-	typs[2] = types.Types[types.TANY]
-	typs[3] = types.NewPtr(typs[2])
-	typs[4] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
-	typs[5] = types.Types[types.TUINTPTR]
-	typs[6] = types.Types[types.TBOOL]
-	typs[7] = types.Types[types.TUNSAFEPTR]
-	typs[8] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[6])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[9] = functype(nil, nil, nil)
-	typs[10] = types.Types[types.TINTER]
-	typs[11] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[10])}, nil)
-	typs[12] = types.Types[types.TINT32]
-	typs[13] = types.NewPtr(typs[12])
-	typs[14] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[13])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[10])})
-	typs[15] = types.Types[types.TINT]
-	typs[16] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15])}, nil)
-	typs[17] = types.Types[types.TUINT]
-	typs[18] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[17]), ir.NewField(base.Pos, nil, nil, typs[15])}, nil)
-	typs[19] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])}, nil)
-	typs[20] = types.Types[types.TFLOAT64]
-	typs[21] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, nil)
-	typs[22] = types.Types[types.TINT64]
-	typs[23] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])}, nil)
-	typs[24] = types.Types[types.TUINT64]
-	typs[25] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])}, nil)
-	typs[26] = types.Types[types.TCOMPLEX128]
-	typs[27] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26])}, nil)
-	typs[28] = types.Types[types.TSTRING]
-	typs[29] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])}, nil)
-	typs[30] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])}, nil)
-	typs[31] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[32] = types.NewArray(typs[0], 32)
-	typs[33] = types.NewPtr(typs[32])
-	typs[34] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[35] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[36] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[37] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[38] = types.NewSlice(typs[28])
-	typs[39] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[38])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[40] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[41] = types.NewArray(typs[0], 4)
-	typs[42] = types.NewPtr(typs[41])
-	typs[43] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[42]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[44] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[45] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[46] = types.RuneType
-	typs[47] = types.NewSlice(typs[46])
-	typs[48] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[47])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
-	typs[49] = types.NewSlice(typs[0])
-	typs[50] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[49])})
-	typs[51] = types.NewArray(typs[46], 32)
-	typs[52] = types.NewPtr(typs[51])
-	typs[53] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[52]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[47])})
-	typs[54] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[55] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[46]), ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[56] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[57] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])})
-	typs[58] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[59] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])})
-	typs[60] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[61] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1])}, nil)
-	typs[62] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1])}, nil)
-	typs[63] = types.NewPtr(typs[5])
-	typs[64] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[63]), ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[65] = types.Types[types.TUINT32]
-	typs[66] = functype(nil, nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])})
-	typs[67] = types.NewMap(typs[2], typs[2])
-	typs[68] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
-	typs[69] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
-	typs[70] = functype(nil, nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
-	typs[71] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
-	typs[72] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
-	typs[73] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
-	typs[74] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[75] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[76] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[77] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[78] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, nil)
-	typs[79] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[80] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67])}, nil)
-	typs[81] = types.NewChan(typs[2], types.Cboth)
-	typs[82] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[81])})
-	typs[83] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[81])})
-	typs[84] = types.NewChan(typs[2], types.Crecv)
-	typs[85] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[84]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[86] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[84]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[87] = types.NewChan(typs[2], types.Csend)
-	typs[88] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[87]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[89] = types.NewArray(typs[0], 3)
-	typs[90] = tostruct([]*ir.Field{ir.NewField(base.Pos, lookup("enabled"), nil, typs[6]), ir.NewField(base.Pos, lookup("pad"), nil, typs[89]), ir.NewField(base.Pos, lookup("needed"), nil, typs[6]), ir.NewField(base.Pos, lookup("cgo"), nil, typs[6]), ir.NewField(base.Pos, lookup("alignme"), nil, typs[24])})
-	typs[91] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[92] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
-	typs[93] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
-	typs[94] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[87]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[95] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[84])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[96] = types.NewPtr(typs[6])
-	typs[97] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[96]), ir.NewField(base.Pos, nil, nil, typs[84])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[98] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[63])}, nil)
-	typs[99] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[63]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[6])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[100] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[101] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[102] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
-	typs[103] = types.NewSlice(typs[2])
-	typs[104] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[103]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[103])})
-	typs[105] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[106] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[107] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[108] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[109] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
-	typs[110] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])})
-	typs[111] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])})
-	typs[112] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])})
-	typs[113] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24]), ir.NewField(base.Pos, nil, nil, typs[24])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])})
-	typs[114] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])})
-	typs[115] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])})
-	typs[116] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])})
-	typs[117] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
-	typs[118] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
-	typs[119] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
-	typs[120] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26]), ir.NewField(base.Pos, nil, nil, typs[26])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26])})
-	typs[121] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[122] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[123] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
-	typs[124] = types.NewSlice(typs[7])
-	typs[125] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[124])}, nil)
-	typs[126] = types.Types[types.TUINT8]
-	typs[127] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[126]), ir.NewField(base.Pos, nil, nil, typs[126])}, nil)
-	typs[128] = types.Types[types.TUINT16]
-	typs[129] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[128]), ir.NewField(base.Pos, nil, nil, typs[128])}, nil)
-	typs[130] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65]), ir.NewField(base.Pos, nil, nil, typs[65])}, nil)
-	typs[131] = functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24]), ir.NewField(base.Pos, nil, nil, typs[24])}, nil)
-	return typs[:]
-}
diff --git a/src/cmd/compile/internal/gc/closure.go b/src/cmd/compile/internal/gc/closure.go
index 454d97e17f..29455bffd8 100644
--- a/src/cmd/compile/internal/gc/closure.go
+++ b/src/cmd/compile/internal/gc/closure.go
@@ -8,9 +8,9 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/syntax"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
-	"fmt"
 )
 
 func (p *noder) funcLit(expr *syntax.FuncLit) ir.Node {
@@ -72,156 +72,6 @@ func (p *noder) funcLit(expr *syntax.FuncLit) ir.Node {
 	return clo
 }
 
-// typecheckclosure typechecks an OCLOSURE node. It also creates the named
-// function associated with the closure.
-// TODO: This creation of the named function should probably really be done in a
-// separate pass from type-checking.
-func typecheckclosure(clo *ir.ClosureExpr, top int) {
-	fn := clo.Func
-	// Set current associated iota value, so iota can be used inside
-	// function in ConstSpec, see issue #22344
-	if x := getIotaValue(); x >= 0 {
-		fn.Iota = x
-	}
-
-	fn.ClosureType = typecheck(fn.ClosureType, ctxType)
-	clo.SetType(fn.ClosureType.Type())
-	fn.SetClosureCalled(top&ctxCallee != 0)
-
-	// Do not typecheck fn twice, otherwise, we will end up pushing
-	// fn to Target.Decls multiple times, causing initLSym called twice.
-	// See #30709
-	if fn.Typecheck() == 1 {
-		return
-	}
-
-	for _, ln := range fn.ClosureVars {
-		n := ln.Defn
-		if !n.Name().Captured() {
-			n.Name().SetCaptured(true)
-			if n.Name().Decldepth == 0 {
-				base.Fatalf("typecheckclosure: var %v does not have decldepth assigned", n)
-			}
-
-			// Ignore assignments to the variable in straightline code
-			// preceding the first capturing by a closure.
-			if n.Name().Decldepth == decldepth {
-				n.Name().SetAssigned(false)
-			}
-		}
-	}
-
-	fn.Nname.SetSym(closurename(ir.CurFunc))
-	ir.MarkFunc(fn.Nname)
-	typecheckFunc(fn)
-
-	// Type check the body now, but only if we're inside a function.
-	// At top level (in a variable initialization: curfn==nil) we're not
-	// ready to type check code yet; we'll check it later, because the
-	// underlying closure function we create is added to Target.Decls.
-	if ir.CurFunc != nil && clo.Type() != nil {
-		oldfn := ir.CurFunc
-		ir.CurFunc = fn
-		olddd := decldepth
-		decldepth = 1
-		typecheckslice(fn.Body, ctxStmt)
-		decldepth = olddd
-		ir.CurFunc = oldfn
-	}
-
-	Target.Decls = append(Target.Decls, fn)
-}
-
-// globClosgen is like Func.Closgen, but for the global scope.
-var globClosgen int32
-
-// closurename generates a new unique name for a closure within
-// outerfunc.
-func closurename(outerfunc *ir.Func) *types.Sym {
-	outer := "glob."
-	prefix := "func"
-	gen := &globClosgen
-
-	if outerfunc != nil {
-		if outerfunc.OClosure != nil {
-			prefix = ""
-		}
-
-		outer = ir.FuncName(outerfunc)
-
-		// There may be multiple functions named "_". In those
-		// cases, we can't use their individual Closgens as it
-		// would lead to name clashes.
-		if !ir.IsBlank(outerfunc.Nname) {
-			gen = &outerfunc.Closgen
-		}
-	}
-
-	*gen++
-	return lookup(fmt.Sprintf("%s.%s%d", outer, prefix, *gen))
-}
-
-// capturevarscomplete is set to true when the capturevars phase is done.
-var capturevarscomplete bool
-
-// capturevars is called in a separate phase after all typechecking is done.
-// It decides whether each variable captured by a closure should be captured
-// by value or by reference.
-// We use value capturing for values <= 128 bytes that are never reassigned
-// after capturing (effectively constant).
-func capturevars(fn *ir.Func) {
-	lno := base.Pos
-	base.Pos = fn.Pos()
-	cvars := fn.ClosureVars
-	out := cvars[:0]
-	for _, v := range cvars {
-		if v.Type() == nil {
-			// If v.Type is nil, it means v looked like it
-			// was going to be used in the closure, but
-			// isn't. This happens in struct literals like
-			// s{f: x} where we can't distinguish whether
-			// f is a field identifier or expression until
-			// resolving s.
-			continue
-		}
-		out = append(out, v)
-
-		// type check the & of closed variables outside the closure,
-		// so that the outer frame also grabs them and knows they escape.
-		types.CalcSize(v.Type())
-
-		var outer ir.Node
-		outer = v.Outer
-		outermost := v.Defn.(*ir.Name)
-
-		// out parameters will be assigned to implicitly upon return.
-		if outermost.Class_ != ir.PPARAMOUT && !outermost.Name().Addrtaken() && !outermost.Name().Assigned() && v.Type().Width <= 128 {
-			v.SetByval(true)
-		} else {
-			outermost.Name().SetAddrtaken(true)
-			outer = nodAddr(outer)
-		}
-
-		if base.Flag.LowerM > 1 {
-			var name *types.Sym
-			if v.Curfn != nil && v.Curfn.Nname != nil {
-				name = v.Curfn.Sym()
-			}
-			how := "ref"
-			if v.Byval() {
-				how = "value"
-			}
-			base.WarnfAt(v.Pos(), "%v capturing by %s: %v (addr=%v assign=%v width=%d)", name, how, v.Sym(), outermost.Name().Addrtaken(), outermost.Name().Assigned(), int32(v.Type().Width))
-		}
-
-		outer = typecheck(outer, ctxExpr)
-		fn.ClosureEnter.Append(outer)
-	}
-
-	fn.ClosureVars = out
-	base.Pos = lno
-}
-
 // transformclosure is called in a separate phase after escape analysis.
 // It transform closure bodies to properly reference captured variables.
 func transformclosure(fn *ir.Func) {
@@ -256,7 +106,7 @@ func transformclosure(fn *ir.Func) {
 				// we introduce function param &v *T
 				// and v remains PAUTOHEAP with &v heapaddr
 				// (accesses will implicitly deref &v).
-				addr := NewName(lookup("&" + v.Sym().Name))
+				addr := typecheck.NewName(typecheck.Lookup("&" + v.Sym().Name))
 				addr.SetType(types.NewPtr(v.Type()))
 				v.Heapaddr = addr
 				v = addr
@@ -300,7 +150,7 @@ func transformclosure(fn *ir.Func) {
 			} else {
 				// Declare variable holding addresses taken from closure
 				// and initialize in entry prologue.
-				addr := NewName(lookup("&" + v.Sym().Name))
+				addr := typecheck.NewName(typecheck.Lookup("&" + v.Sym().Name))
 				addr.SetType(types.NewPtr(v.Type()))
 				addr.Class_ = ir.PAUTO
 				addr.SetUsed(true)
@@ -309,14 +159,14 @@ func transformclosure(fn *ir.Func) {
 				v.Heapaddr = addr
 				var src ir.Node = cr
 				if v.Byval() {
-					src = nodAddr(cr)
+					src = typecheck.NodAddr(cr)
 				}
 				body = append(body, ir.NewAssignStmt(base.Pos, addr, src))
 			}
 		}
 
 		if len(body) > 0 {
-			typecheckslice(body, ctxStmt)
+			typecheck.Stmts(body)
 			fn.Enter.Set(body)
 			fn.SetNeedctxt(true)
 		}
@@ -346,38 +196,6 @@ func closuredebugruntimecheck(clo *ir.ClosureExpr) {
 	}
 }
 
-// closureType returns the struct type used to hold all the information
-// needed in the closure for clo (clo must be a OCLOSURE node).
-// The address of a variable of the returned type can be cast to a func.
-func closureType(clo *ir.ClosureExpr) *types.Type {
-	// Create closure in the form of a composite literal.
-	// supposing the closure captures an int i and a string s
-	// and has one float64 argument and no results,
-	// the generated code looks like:
-	//
-	//	clos = &struct{.F uintptr; i *int; s *string}{func.1, &i, &s}
-	//
-	// The use of the struct provides type information to the garbage
-	// collector so that it can walk the closure. We could use (in this case)
-	// [3]unsafe.Pointer instead, but that would leave the gc in the dark.
-	// The information appears in the binary in the form of type descriptors;
-	// the struct is unnamed so that closures in multiple packages with the
-	// same struct type can share the descriptor.
-	fields := []*ir.Field{
-		ir.NewField(base.Pos, lookup(".F"), nil, types.Types[types.TUINTPTR]),
-	}
-	for _, v := range clo.Func.ClosureVars {
-		typ := v.Type()
-		if !v.Byval() {
-			typ = types.NewPtr(typ)
-		}
-		fields = append(fields, ir.NewField(base.Pos, v.Sym(), nil, typ))
-	}
-	typ := tostruct(fields)
-	typ.SetNoalg(true)
-	return typ
-}
-
 func walkclosure(clo *ir.ClosureExpr, init *ir.Nodes) ir.Node {
 	fn := clo.Func
 
@@ -390,17 +208,17 @@ func walkclosure(clo *ir.ClosureExpr, init *ir.Nodes) ir.Node {
 	}
 	closuredebugruntimecheck(clo)
 
-	typ := closureType(clo)
+	typ := typecheck.ClosureType(clo)
 
 	clos := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(typ).(ir.Ntype), nil)
 	clos.SetEsc(clo.Esc())
 	clos.List.Set(append([]ir.Node{ir.NewUnaryExpr(base.Pos, ir.OCFUNC, fn.Nname)}, fn.ClosureEnter...))
 
-	addr := nodAddr(clos)
+	addr := typecheck.NodAddr(clos)
 	addr.SetEsc(clo.Esc())
 
 	// Force type conversion from *struct to the func type.
-	cfn := convnop(addr, clo.Type())
+	cfn := typecheck.ConvNop(addr, clo.Type())
 
 	// non-escaping temp to use, if any.
 	if x := clo.Prealloc; x != nil {
@@ -414,110 +232,6 @@ func walkclosure(clo *ir.ClosureExpr, init *ir.Nodes) ir.Node {
 	return walkexpr(cfn, init)
 }
 
-func typecheckpartialcall(n ir.Node, sym *types.Sym) *ir.CallPartExpr {
-	switch n.Op() {
-	case ir.ODOTINTER, ir.ODOTMETH:
-		break
-
-	default:
-		base.Fatalf("invalid typecheckpartialcall")
-	}
-	dot := n.(*ir.SelectorExpr)
-
-	// Create top-level function.
-	fn := makepartialcall(dot, dot.Type(), sym)
-	fn.SetWrapper(true)
-
-	return ir.NewCallPartExpr(dot.Pos(), dot.X, dot.Selection, fn)
-}
-
-// makepartialcall returns a DCLFUNC node representing the wrapper function (*-fm) needed
-// for partial calls.
-func makepartialcall(dot *ir.SelectorExpr, t0 *types.Type, meth *types.Sym) *ir.Func {
-	rcvrtype := dot.X.Type()
-	sym := ir.MethodSymSuffix(rcvrtype, meth, "-fm")
-
-	if sym.Uniq() {
-		return sym.Def.(*ir.Func)
-	}
-	sym.SetUniq(true)
-
-	savecurfn := ir.CurFunc
-	saveLineNo := base.Pos
-	ir.CurFunc = nil
-
-	// Set line number equal to the line number where the method is declared.
-	var m *types.Field
-	if lookdot0(meth, rcvrtype, &m, false) == 1 && m.Pos.IsKnown() {
-		base.Pos = m.Pos
-	}
-	// Note: !m.Pos.IsKnown() happens for method expressions where
-	// the method is implicitly declared. The Error method of the
-	// built-in error type is one such method.  We leave the line
-	// number at the use of the method expression in this
-	// case. See issue 29389.
-
-	tfn := ir.NewFuncType(base.Pos, nil,
-		structargs(t0.Params(), true),
-		structargs(t0.Results(), false))
-
-	fn := dclfunc(sym, tfn)
-	fn.SetDupok(true)
-	fn.SetNeedctxt(true)
-
-	// Declare and initialize variable holding receiver.
-	cr := ir.NewClosureRead(rcvrtype, types.Rnd(int64(types.PtrSize), int64(rcvrtype.Align)))
-	ptr := NewName(lookup(".this"))
-	declare(ptr, ir.PAUTO)
-	ptr.SetUsed(true)
-	var body []ir.Node
-	if rcvrtype.IsPtr() || rcvrtype.IsInterface() {
-		ptr.SetType(rcvrtype)
-		body = append(body, ir.NewAssignStmt(base.Pos, ptr, cr))
-	} else {
-		ptr.SetType(types.NewPtr(rcvrtype))
-		body = append(body, ir.NewAssignStmt(base.Pos, ptr, nodAddr(cr)))
-	}
-
-	call := ir.NewCallExpr(base.Pos, ir.OCALL, ir.NewSelectorExpr(base.Pos, ir.OXDOT, ptr, meth), nil)
-	call.Args.Set(ir.ParamNames(tfn.Type()))
-	call.IsDDD = tfn.Type().IsVariadic()
-	if t0.NumResults() != 0 {
-		ret := ir.NewReturnStmt(base.Pos, nil)
-		ret.Results = []ir.Node{call}
-		body = append(body, ret)
-	} else {
-		body = append(body, call)
-	}
-
-	fn.Body.Set(body)
-	funcbody()
-
-	typecheckFunc(fn)
-	// Need to typecheck the body of the just-generated wrapper.
-	// typecheckslice() requires that Curfn is set when processing an ORETURN.
-	ir.CurFunc = fn
-	typecheckslice(fn.Body, ctxStmt)
-	sym.Def = fn
-	Target.Decls = append(Target.Decls, fn)
-	ir.CurFunc = savecurfn
-	base.Pos = saveLineNo
-
-	return fn
-}
-
-// partialCallType returns the struct type used to hold all the information
-// needed in the closure for n (n must be a OCALLPART node).
-// The address of a variable of the returned type can be cast to a func.
-func partialCallType(n *ir.CallPartExpr) *types.Type {
-	t := tostruct([]*ir.Field{
-		ir.NewField(base.Pos, lookup("F"), nil, types.Types[types.TUINTPTR]),
-		ir.NewField(base.Pos, lookup("R"), nil, n.X.Type()),
-	})
-	t.SetNoalg(true)
-	return t
-}
-
 func walkpartialcall(n *ir.CallPartExpr, init *ir.Nodes) ir.Node {
 	// Create closure in the form of a composite literal.
 	// For x.M with receiver (x) type T, the generated code looks like:
@@ -532,24 +246,24 @@ func walkpartialcall(n *ir.CallPartExpr, init *ir.Nodes) ir.Node {
 		n.X = cheapexpr(n.X, init)
 		n.X = walkexpr(n.X, nil)
 
-		tab := typecheck(ir.NewUnaryExpr(base.Pos, ir.OITAB, n.X), ctxExpr)
+		tab := typecheck.Expr(ir.NewUnaryExpr(base.Pos, ir.OITAB, n.X))
 
 		c := ir.NewUnaryExpr(base.Pos, ir.OCHECKNIL, tab)
 		c.SetTypecheck(1)
 		init.Append(c)
 	}
 
-	typ := partialCallType(n)
+	typ := typecheck.PartialCallType(n)
 
 	clos := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(typ).(ir.Ntype), nil)
 	clos.SetEsc(n.Esc())
 	clos.List = []ir.Node{ir.NewUnaryExpr(base.Pos, ir.OCFUNC, n.Func.Nname), n.X}
 
-	addr := nodAddr(clos)
+	addr := typecheck.NodAddr(clos)
 	addr.SetEsc(n.Esc())
 
 	// Force type conversion from *struct to the func type.
-	cfn := convnop(addr, n.Type())
+	cfn := typecheck.ConvNop(addr, n.Type())
 
 	// non-escaping temp to use, if any.
 	if x := n.Prealloc; x != nil {
diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index 1189d0ec12..e53bba44ad 100644
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -8,11 +8,11 @@ import (
 	"bytes"
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/src"
 	"fmt"
-	"strings"
 )
 
 func EnableNoWriteBarrierRecCheck() {
@@ -28,154 +28,6 @@ func NoWriteBarrierRecCheck() {
 
 var nowritebarrierrecCheck *nowritebarrierrecChecker
 
-// redeclare emits a diagnostic about symbol s being redeclared at pos.
-func redeclare(pos src.XPos, s *types.Sym, where string) {
-	if !s.Lastlineno.IsKnown() {
-		pkgName := dotImportRefs[s.Def.(*ir.Ident)]
-		base.ErrorfAt(pos, "%v redeclared %s\n"+
-			"\t%v: previous declaration during import %q", s, where, base.FmtPos(pkgName.Pos()), pkgName.Pkg.Path)
-	} else {
-		prevPos := s.Lastlineno
-
-		// When an import and a declaration collide in separate files,
-		// present the import as the "redeclared", because the declaration
-		// is visible where the import is, but not vice versa.
-		// See issue 4510.
-		if s.Def == nil {
-			pos, prevPos = prevPos, pos
-		}
-
-		base.ErrorfAt(pos, "%v redeclared %s\n"+
-			"\t%v: previous declaration", s, where, base.FmtPos(prevPos))
-	}
-}
-
-var vargen int
-
-// declare individual names - var, typ, const
-
-var declare_typegen int
-
-// declare records that Node n declares symbol n.Sym in the specified
-// declaration context.
-func declare(n *ir.Name, ctxt ir.Class) {
-	if ir.IsBlank(n) {
-		return
-	}
-
-	s := n.Sym()
-
-	// kludgy: typecheckok means we're past parsing. Eg genwrapper may declare out of package names later.
-	if !inimport && !typecheckok && s.Pkg != types.LocalPkg {
-		base.ErrorfAt(n.Pos(), "cannot declare name %v", s)
-	}
-
-	gen := 0
-	if ctxt == ir.PEXTERN {
-		if s.Name == "init" {
-			base.ErrorfAt(n.Pos(), "cannot declare init - must be func")
-		}
-		if s.Name == "main" && s.Pkg.Name == "main" {
-			base.ErrorfAt(n.Pos(), "cannot declare main - must be func")
-		}
-		Target.Externs = append(Target.Externs, n)
-	} else {
-		if ir.CurFunc == nil && ctxt == ir.PAUTO {
-			base.Pos = n.Pos()
-			base.Fatalf("automatic outside function")
-		}
-		if ir.CurFunc != nil && ctxt != ir.PFUNC && n.Op() == ir.ONAME {
-			ir.CurFunc.Dcl = append(ir.CurFunc.Dcl, n)
-		}
-		if n.Op() == ir.OTYPE {
-			declare_typegen++
-			gen = declare_typegen
-		} else if n.Op() == ir.ONAME && ctxt == ir.PAUTO && !strings.Contains(s.Name, "·") {
-			vargen++
-			gen = vargen
-		}
-		types.Pushdcl(s)
-		n.Curfn = ir.CurFunc
-	}
-
-	if ctxt == ir.PAUTO {
-		n.SetFrameOffset(0)
-	}
-
-	if s.Block == types.Block {
-		// functype will print errors about duplicate function arguments.
-		// Don't repeat the error here.
-		if ctxt != ir.PPARAM && ctxt != ir.PPARAMOUT {
-			redeclare(n.Pos(), s, "in this block")
-		}
-	}
-
-	s.Block = types.Block
-	s.Lastlineno = base.Pos
-	s.Def = n
-	n.Vargen = int32(gen)
-	n.Class_ = ctxt
-	if ctxt == ir.PFUNC {
-		n.Sym().SetFunc(true)
-	}
-
-	autoexport(n, ctxt)
-}
-
-// declare variables from grammar
-// new_name_list (type | [type] = expr_list)
-func variter(vl []*ir.Name, t ir.Ntype, el []ir.Node) []ir.Node {
-	var init []ir.Node
-	doexpr := len(el) > 0
-
-	if len(el) == 1 && len(vl) > 1 {
-		e := el[0]
-		as2 := ir.NewAssignListStmt(base.Pos, ir.OAS2, nil, nil)
-		as2.Rhs = []ir.Node{e}
-		for _, v := range vl {
-			as2.Lhs.Append(v)
-			declare(v, dclcontext)
-			v.Ntype = t
-			v.Defn = as2
-			if ir.CurFunc != nil {
-				init = append(init, ir.NewDecl(base.Pos, ir.ODCL, v))
-			}
-		}
-
-		return append(init, as2)
-	}
-
-	for i, v := range vl {
-		var e ir.Node
-		if doexpr {
-			if i >= len(el) {
-				base.Errorf("assignment mismatch: %d variables but %d values", len(vl), len(el))
-				break
-			}
-			e = el[i]
-		}
-
-		declare(v, dclcontext)
-		v.Ntype = t
-
-		if e != nil || ir.CurFunc != nil || ir.IsBlank(v) {
-			if ir.CurFunc != nil {
-				init = append(init, ir.NewDecl(base.Pos, ir.ODCL, v))
-			}
-			as := ir.NewAssignStmt(base.Pos, v, e)
-			init = append(init, as)
-			if e != nil {
-				v.Defn = as
-			}
-		}
-	}
-
-	if len(el) > len(vl) {
-		base.Errorf("assignment mismatch: %d variables but %d values", len(vl), len(el))
-	}
-	return init
-}
-
 // oldname returns the Node that declares symbol s in the current scope.
 // If no such Node currently exists, an ONONAME Node is returned instead.
 // Automatically creates a new closure variable if the referenced symbol was
@@ -204,7 +56,7 @@ func oldname(s *types.Sym) ir.Node {
 		c := n.Name().Innermost
 		if c == nil || c.Curfn != ir.CurFunc {
 			// Do not have a closure var for the active closure yet; make one.
-			c = NewName(s)
+			c = typecheck.NewName(s)
 			c.Class_ = ir.PAUTOHEAP
 			c.SetIsClosureVar(true)
 			c.SetIsDDD(n.IsDDD())
@@ -236,419 +88,10 @@ func importName(sym *types.Sym) ir.Node {
 	return n
 }
 
-// := declarations
-func colasname(n ir.Node) bool {
-	switch n.Op() {
-	case ir.ONAME,
-		ir.ONONAME,
-		ir.OPACK,
-		ir.OTYPE,
-		ir.OLITERAL:
-		return n.Sym() != nil
-	}
-
-	return false
-}
-
-func colasdefn(left []ir.Node, defn ir.Node) {
-	for _, n := range left {
-		if n.Sym() != nil {
-			n.Sym().SetUniq(true)
-		}
-	}
-
-	var nnew, nerr int
-	for i, n := range left {
-		if ir.IsBlank(n) {
-			continue
-		}
-		if !colasname(n) {
-			base.ErrorfAt(defn.Pos(), "non-name %v on left side of :=", n)
-			nerr++
-			continue
-		}
-
-		if !n.Sym().Uniq() {
-			base.ErrorfAt(defn.Pos(), "%v repeated on left side of :=", n.Sym())
-			n.SetDiag(true)
-			nerr++
-			continue
-		}
-
-		n.Sym().SetUniq(false)
-		if n.Sym().Block == types.Block {
-			continue
-		}
-
-		nnew++
-		n := NewName(n.Sym())
-		declare(n, dclcontext)
-		n.Defn = defn
-		defn.PtrInit().Append(ir.NewDecl(base.Pos, ir.ODCL, n))
-		left[i] = n
-	}
-
-	if nnew == 0 && nerr == 0 {
-		base.ErrorfAt(defn.Pos(), "no new variables on left side of :=")
-	}
-}
-
-// declare the function proper
-// and declare the arguments.
-// called in extern-declaration context
-// returns in auto-declaration context.
-func funchdr(fn *ir.Func) {
-	// change the declaration context from extern to auto
-	funcStack = append(funcStack, funcStackEnt{ir.CurFunc, dclcontext})
-	ir.CurFunc = fn
-	dclcontext = ir.PAUTO
-
-	types.Markdcl()
-
-	if fn.Nname.Ntype != nil {
-		funcargs(fn.Nname.Ntype.(*ir.FuncType))
-	} else {
-		funcargs2(fn.Type())
-	}
-}
-
-func funcargs(nt *ir.FuncType) {
-	if nt.Op() != ir.OTFUNC {
-		base.Fatalf("funcargs %v", nt.Op())
-	}
-
-	// re-start the variable generation number
-	// we want to use small numbers for the return variables,
-	// so let them have the chunk starting at 1.
-	//
-	// TODO(mdempsky): This is ugly, and only necessary because
-	// esc.go uses Vargen to figure out result parameters' index
-	// within the result tuple.
-	vargen = len(nt.Results)
-
-	// declare the receiver and in arguments.
-	if nt.Recv != nil {
-		funcarg(nt.Recv, ir.PPARAM)
-	}
-	for _, n := range nt.Params {
-		funcarg(n, ir.PPARAM)
-	}
-
-	oldvargen := vargen
-	vargen = 0
-
-	// declare the out arguments.
-	gen := len(nt.Params)
-	for _, n := range nt.Results {
-		if n.Sym == nil {
-			// Name so that escape analysis can track it. ~r stands for 'result'.
-			n.Sym = lookupN("~r", gen)
-			gen++
-		}
-		if n.Sym.IsBlank() {
-			// Give it a name so we can assign to it during return. ~b stands for 'blank'.
-			// The name must be different from ~r above because if you have
-			//	func f() (_ int)
-			//	func g() int
-			// f is allowed to use a plain 'return' with no arguments, while g is not.
-			// So the two cases must be distinguished.
-			n.Sym = lookupN("~b", gen)
-			gen++
-		}
-
-		funcarg(n, ir.PPARAMOUT)
-	}
-
-	vargen = oldvargen
-}
-
-func funcarg(n *ir.Field, ctxt ir.Class) {
-	if n.Sym == nil {
-		return
-	}
-
-	name := ir.NewNameAt(n.Pos, n.Sym)
-	n.Decl = name
-	name.Ntype = n.Ntype
-	name.SetIsDDD(n.IsDDD)
-	declare(name, ctxt)
-
-	vargen++
-	n.Decl.Vargen = int32(vargen)
-}
-
-// Same as funcargs, except run over an already constructed TFUNC.
-// This happens during import, where the hidden_fndcl rule has
-// used functype directly to parse the function's type.
-func funcargs2(t *types.Type) {
-	if t.Kind() != types.TFUNC {
-		base.Fatalf("funcargs2 %v", t)
-	}
-
-	for _, f := range t.Recvs().Fields().Slice() {
-		funcarg2(f, ir.PPARAM)
-	}
-	for _, f := range t.Params().Fields().Slice() {
-		funcarg2(f, ir.PPARAM)
-	}
-	for _, f := range t.Results().Fields().Slice() {
-		funcarg2(f, ir.PPARAMOUT)
-	}
-}
-
-func funcarg2(f *types.Field, ctxt ir.Class) {
-	if f.Sym == nil {
-		return
-	}
-	n := ir.NewNameAt(f.Pos, f.Sym)
-	f.Nname = n
-	n.SetType(f.Type)
-	n.SetIsDDD(f.IsDDD())
-	declare(n, ctxt)
-}
-
-var funcStack []funcStackEnt // stack of previous values of Curfn/dclcontext
-
-type funcStackEnt struct {
-	curfn      *ir.Func
-	dclcontext ir.Class
-}
-
-func CheckFuncStack() {
-	if len(funcStack) != 0 {
-		base.Fatalf("funcStack is non-empty: %v", len(funcStack))
-	}
-}
-
-// finish the body.
-// called in auto-declaration context.
-// returns in extern-declaration context.
-func funcbody() {
-	// change the declaration context from auto to previous context
-	types.Popdcl()
-	var e funcStackEnt
-	funcStack, e = funcStack[:len(funcStack)-1], funcStack[len(funcStack)-1]
-	ir.CurFunc, dclcontext = e.curfn, e.dclcontext
-}
-
-// structs, functions, and methods.
-// they don't belong here, but where do they belong?
-func checkembeddedtype(t *types.Type) {
-	if t == nil {
-		return
-	}
-
-	if t.Sym() == nil && t.IsPtr() {
-		t = t.Elem()
-		if t.IsInterface() {
-			base.Errorf("embedded type cannot be a pointer to interface")
-		}
-	}
-
-	if t.IsPtr() || t.IsUnsafePtr() {
-		base.Errorf("embedded type cannot be a pointer")
-	} else if t.Kind() == types.TFORW && !t.ForwardType().Embedlineno.IsKnown() {
-		t.ForwardType().Embedlineno = base.Pos
-	}
-}
-
-// checkdupfields emits errors for duplicately named fields or methods in
-// a list of struct or interface types.
-func checkdupfields(what string, fss ...[]*types.Field) {
-	seen := make(map[*types.Sym]bool)
-	for _, fs := range fss {
-		for _, f := range fs {
-			if f.Sym == nil || f.Sym.IsBlank() {
-				continue
-			}
-			if seen[f.Sym] {
-				base.ErrorfAt(f.Pos, "duplicate %s %s", what, f.Sym.Name)
-				continue
-			}
-			seen[f.Sym] = true
-		}
-	}
-}
-
-// convert a parsed id/type list into
-// a type for struct/interface/arglist
-func tostruct(l []*ir.Field) *types.Type {
-	lno := base.Pos
-
-	fields := make([]*types.Field, len(l))
-	for i, n := range l {
-		base.Pos = n.Pos
-
-		if n.Ntype != nil {
-			n.Type = typecheckNtype(n.Ntype).Type()
-			n.Ntype = nil
-		}
-		f := types.NewField(n.Pos, n.Sym, n.Type)
-		if n.Embedded {
-			checkembeddedtype(n.Type)
-			f.Embedded = 1
-		}
-		f.Note = n.Note
-		fields[i] = f
-	}
-	checkdupfields("field", fields)
-
-	base.Pos = lno
-	return types.NewStruct(types.LocalPkg, fields)
-}
-
-func tointerface(nmethods []*ir.Field) *types.Type {
-	if len(nmethods) == 0 {
-		return types.Types[types.TINTER]
-	}
-
-	lno := base.Pos
-
-	methods := make([]*types.Field, len(nmethods))
-	for i, n := range nmethods {
-		base.Pos = n.Pos
-		if n.Ntype != nil {
-			n.Type = typecheckNtype(n.Ntype).Type()
-			n.Ntype = nil
-		}
-		methods[i] = types.NewField(n.Pos, n.Sym, n.Type)
-	}
-
-	base.Pos = lno
-	return types.NewInterface(types.LocalPkg, methods)
-}
-
 func fakeRecv() *ir.Field {
 	return ir.NewField(base.Pos, nil, nil, types.FakeRecvType())
 }
 
-func fakeRecvField() *types.Field {
-	return types.NewField(src.NoXPos, nil, types.FakeRecvType())
-}
-
-// turn a parsed function declaration into a type
-func functype(nrecv *ir.Field, nparams, nresults []*ir.Field) *types.Type {
-	funarg := func(n *ir.Field) *types.Field {
-		lno := base.Pos
-		base.Pos = n.Pos
-
-		if n.Ntype != nil {
-			n.Type = typecheckNtype(n.Ntype).Type()
-			n.Ntype = nil
-		}
-
-		f := types.NewField(n.Pos, n.Sym, n.Type)
-		f.SetIsDDD(n.IsDDD)
-		if n.Decl != nil {
-			n.Decl.SetType(f.Type)
-			f.Nname = n.Decl
-		}
-
-		base.Pos = lno
-		return f
-	}
-	funargs := func(nn []*ir.Field) []*types.Field {
-		res := make([]*types.Field, len(nn))
-		for i, n := range nn {
-			res[i] = funarg(n)
-		}
-		return res
-	}
-
-	var recv *types.Field
-	if nrecv != nil {
-		recv = funarg(nrecv)
-	}
-
-	t := types.NewSignature(types.LocalPkg, recv, funargs(nparams), funargs(nresults))
-	checkdupfields("argument", t.Recvs().FieldSlice(), t.Params().FieldSlice(), t.Results().FieldSlice())
-	return t
-}
-
-// Add a method, declared as a function.
-// - msym is the method symbol
-// - t is function type (with receiver)
-// Returns a pointer to the existing or added Field; or nil if there's an error.
-func addmethod(n *ir.Func, msym *types.Sym, t *types.Type, local, nointerface bool) *types.Field {
-	if msym == nil {
-		base.Fatalf("no method symbol")
-	}
-
-	// get parent type sym
-	rf := t.Recv() // ptr to this structure
-	if rf == nil {
-		base.Errorf("missing receiver")
-		return nil
-	}
-
-	mt := types.ReceiverBaseType(rf.Type)
-	if mt == nil || mt.Sym() == nil {
-		pa := rf.Type
-		t := pa
-		if t != nil && t.IsPtr() {
-			if t.Sym() != nil {
-				base.Errorf("invalid receiver type %v (%v is a pointer type)", pa, t)
-				return nil
-			}
-			t = t.Elem()
-		}
-
-		switch {
-		case t == nil || t.Broke():
-			// rely on typecheck having complained before
-		case t.Sym() == nil:
-			base.Errorf("invalid receiver type %v (%v is not a defined type)", pa, t)
-		case t.IsPtr():
-			base.Errorf("invalid receiver type %v (%v is a pointer type)", pa, t)
-		case t.IsInterface():
-			base.Errorf("invalid receiver type %v (%v is an interface type)", pa, t)
-		default:
-			// Should have picked off all the reasons above,
-			// but just in case, fall back to generic error.
-			base.Errorf("invalid receiver type %v (%L / %L)", pa, pa, t)
-		}
-		return nil
-	}
-
-	if local && mt.Sym().Pkg != types.LocalPkg {
-		base.Errorf("cannot define new methods on non-local type %v", mt)
-		return nil
-	}
-
-	if msym.IsBlank() {
-		return nil
-	}
-
-	if mt.IsStruct() {
-		for _, f := range mt.Fields().Slice() {
-			if f.Sym == msym {
-				base.Errorf("type %v has both field and method named %v", mt, msym)
-				f.SetBroke(true)
-				return nil
-			}
-		}
-	}
-
-	for _, f := range mt.Methods().Slice() {
-		if msym.Name != f.Sym.Name {
-			continue
-		}
-		// types.Identical only checks that incoming and result parameters match,
-		// so explicitly check that the receiver parameters match too.
-		if !types.Identical(t, f.Type) || !types.Identical(t.Recv().Type, f.Type.Recv().Type) {
-			base.Errorf("method redeclared: %v.%v\n\t%v\n\t%v", mt, msym, f.Type, t)
-		}
-		return f
-	}
-
-	f := types.NewField(base.Pos, msym, t)
-	f.Nname = n.Nname
-	f.SetNointerface(nointerface)
-
-	mt.Methods().Append(f)
-	return f
-}
-
 // funcsym returns s·f.
 func funcsym(s *types.Sym) *types.Sym {
 	// funcsymsmu here serves to protect not just mutations of funcsyms (below),
@@ -700,21 +143,6 @@ func makefuncsym(s *types.Sym) {
 	}
 }
 
-func dclfunc(sym *types.Sym, tfn ir.Ntype) *ir.Func {
-	if tfn.Op() != ir.OTFUNC {
-		base.Fatalf("expected OTFUNC node, got %v", tfn)
-	}
-
-	fn := ir.NewFunc(base.Pos)
-	fn.Nname = ir.NewFuncNameAt(base.Pos, sym, fn)
-	fn.Nname.Defn = fn
-	fn.Nname.Ntype = tfn
-	ir.MarkFunc(fn.Nname)
-	funchdr(fn)
-	fn.Nname.Ntype = typecheckNtype(fn.Nname.Ntype)
-	return fn
-}
-
 type nowritebarrierrecChecker struct {
 	// extraCalls contains extra function calls that may not be
 	// visible during later analysis. It maps from the ODCLFUNC of
@@ -742,7 +170,7 @@ func newNowritebarrierrecChecker() *nowritebarrierrecChecker {
 	// important to handle it for this check, so we model it
 	// directly. This has to happen before transformclosure since
 	// it's a lot harder to work out the argument after.
-	for _, n := range Target.Decls {
+	for _, n := range typecheck.Target.Decls {
 		if n.Op() != ir.ODCLFUNC {
 			continue
 		}
@@ -819,7 +247,7 @@ func (c *nowritebarrierrecChecker) check() {
 	// q is the queue of ODCLFUNC Nodes to visit in BFS order.
 	var q ir.NameQueue
 
-	for _, n := range Target.Decls {
+	for _, n := range typecheck.Target.Decls {
 		if n.Op() != ir.ODCLFUNC {
 			continue
 		}
diff --git a/src/cmd/compile/internal/gc/embed.go b/src/cmd/compile/internal/gc/embed.go
index 70c5c2a25a..bcfec3cad3 100644
--- a/src/cmd/compile/internal/gc/embed.go
+++ b/src/cmd/compile/internal/gc/embed.go
@@ -8,6 +8,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/syntax"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 
@@ -61,13 +62,13 @@ func varEmbed(p *noder, names []*ir.Name, typ ir.Ntype, exprs []ir.Node, embeds
 		p.errorAt(pos, "go:embed cannot apply to var without type")
 		return exprs
 	}
-	if dclcontext != ir.PEXTERN {
+	if typecheck.DeclContext != ir.PEXTERN {
 		p.errorAt(pos, "go:embed cannot apply to var inside func")
 		return exprs
 	}
 
 	v := names[0]
-	Target.Embeds = append(Target.Embeds, v)
+	typecheck.Target.Embeds = append(typecheck.Target.Embeds, v)
 	v.Embed = new([]ir.Embed)
 	for _, e := range embeds {
 		*v.Embed = append(*v.Embed, ir.Embed{Pos: p.makeXPos(e.Pos), Patterns: e.Patterns})
@@ -184,7 +185,7 @@ func embedFileLess(x, y string) bool {
 }
 
 func dumpembeds() {
-	for _, v := range Target.Embeds {
+	for _, v := range typecheck.Target.Embeds {
 		initEmbed(v)
 	}
 }
diff --git a/src/cmd/compile/internal/gc/escape.go b/src/cmd/compile/internal/gc/escape.go
index 6843d8b00e..187313695f 100644
--- a/src/cmd/compile/internal/gc/escape.go
+++ b/src/cmd/compile/internal/gc/escape.go
@@ -8,6 +8,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/logopt"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
 	"fmt"
@@ -870,7 +871,7 @@ func (e *Escape) call(ks []EscHole, call, where ir.Node) {
 
 	case ir.OCALLFUNC, ir.OCALLMETH, ir.OCALLINTER:
 		call := call.(*ir.CallExpr)
-		fixVariadicCall(call)
+		typecheck.FixVariadicCall(call)
 
 		// Pick out the function callee, if statically known.
 		var fn *ir.Name
@@ -1877,10 +1878,10 @@ func heapAllocReason(n ir.Node) string {
 		return "too large for stack"
 	}
 
-	if n.Op() == ir.OCLOSURE && closureType(n.(*ir.ClosureExpr)).Size() >= ir.MaxImplicitStackVarSize {
+	if n.Op() == ir.OCLOSURE && typecheck.ClosureType(n.(*ir.ClosureExpr)).Size() >= ir.MaxImplicitStackVarSize {
 		return "too large for stack"
 	}
-	if n.Op() == ir.OCALLPART && partialCallType(n.(*ir.CallPartExpr)).Size() >= ir.MaxImplicitStackVarSize {
+	if n.Op() == ir.OCALLPART && typecheck.PartialCallType(n.(*ir.CallPartExpr)).Size() >= ir.MaxImplicitStackVarSize {
 		return "too large for stack"
 	}
 
@@ -1992,8 +1993,8 @@ func moveToHeap(n *ir.Name) {
 
 	// Allocate a local stack variable to hold the pointer to the heap copy.
 	// temp will add it to the function declaration list automatically.
-	heapaddr := temp(types.NewPtr(n.Type()))
-	heapaddr.SetSym(lookup("&" + n.Sym().Name))
+	heapaddr := typecheck.Temp(types.NewPtr(n.Type()))
+	heapaddr.SetSym(typecheck.Lookup("&" + n.Sym().Name))
 	heapaddr.SetPos(n.Pos())
 
 	// Unset AutoTemp to persist the &foo variable name through SSA to
@@ -2013,7 +2014,7 @@ func moveToHeap(n *ir.Name) {
 		// Preserve a copy so we can still write code referring to the original,
 		// and substitute that copy into the function declaration list
 		// so that analyses of the local (on-stack) variables use it.
-		stackcopy := NewName(n.Sym())
+		stackcopy := typecheck.NewName(n.Sym())
 		stackcopy.SetType(n.Type())
 		stackcopy.SetFrameOffset(n.FrameOffset())
 		stackcopy.Class_ = n.Class_
diff --git a/src/cmd/compile/internal/gc/export.go b/src/cmd/compile/internal/gc/export.go
index 2855f815be..a414962431 100644
--- a/src/cmd/compile/internal/gc/export.go
+++ b/src/cmd/compile/internal/gc/export.go
@@ -7,9 +7,9 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/bio"
-	"cmd/internal/src"
 	"fmt"
 	"go/constant"
 )
@@ -21,54 +21,16 @@ func exportf(bout *bio.Writer, format string, args ...interface{}) {
 	}
 }
 
-// exportsym marks n for export (or reexport).
-func exportsym(n *ir.Name) {
-	if n.Sym().OnExportList() {
-		return
-	}
-	n.Sym().SetOnExportList(true)
-
-	if base.Flag.E != 0 {
-		fmt.Printf("export symbol %v\n", n.Sym())
-	}
-
-	Target.Exports = append(Target.Exports, n)
-}
-
-func initname(s string) bool {
-	return s == "init"
-}
-
-func autoexport(n *ir.Name, ctxt ir.Class) {
-	if n.Sym().Pkg != types.LocalPkg {
-		return
-	}
-	if (ctxt != ir.PEXTERN && ctxt != ir.PFUNC) || dclcontext != ir.PEXTERN {
-		return
-	}
-	if n.Type() != nil && n.Type().IsKind(types.TFUNC) && ir.IsMethod(n) {
-		return
-	}
-
-	if types.IsExported(n.Sym().Name) || initname(n.Sym().Name) {
-		exportsym(n)
-	}
-	if base.Flag.AsmHdr != "" && !n.Sym().Asm() {
-		n.Sym().SetAsm(true)
-		Target.Asms = append(Target.Asms, n)
-	}
-}
-
 func dumpexport(bout *bio.Writer) {
 	p := &exporter{marked: make(map[*types.Type]bool)}
-	for _, n := range Target.Exports {
+	for _, n := range typecheck.Target.Exports {
 		p.markObject(n)
 	}
 
 	// The linker also looks for the $$ marker - use char after $$ to distinguish format.
 	exportf(bout, "\n$$B\n") // indicate binary export format
 	off := bout.Offset()
-	iexport(bout.Writer)
+	typecheck.WriteExports(bout.Writer)
 	size := bout.Offset() - off
 	exportf(bout, "\n$$\n")
 
@@ -77,78 +39,13 @@ func dumpexport(bout *bio.Writer) {
 	}
 }
 
-func importsym(ipkg *types.Pkg, pos src.XPos, s *types.Sym, op ir.Op, ctxt ir.Class) *ir.Name {
-	if n := s.PkgDef(); n != nil {
-		base.Fatalf("importsym of symbol that already exists: %v", n)
-	}
-
-	n := ir.NewDeclNameAt(pos, op, s)
-	n.Class_ = ctxt // TODO(mdempsky): Move this into NewDeclNameAt too?
-	s.SetPkgDef(n)
-	s.Importdef = ipkg
-	return n
-}
-
-// importtype returns the named type declared by symbol s.
-// If no such type has been declared yet, a forward declaration is returned.
-// ipkg is the package being imported
-func importtype(ipkg *types.Pkg, pos src.XPos, s *types.Sym) *ir.Name {
-	n := importsym(ipkg, pos, s, ir.OTYPE, ir.PEXTERN)
-	n.SetType(types.NewNamed(n))
-	return n
-}
-
-// importobj declares symbol s as an imported object representable by op.
-// ipkg is the package being imported
-func importobj(ipkg *types.Pkg, pos src.XPos, s *types.Sym, op ir.Op, ctxt ir.Class, t *types.Type) *ir.Name {
-	n := importsym(ipkg, pos, s, op, ctxt)
-	n.SetType(t)
-	if ctxt == ir.PFUNC {
-		n.Sym().SetFunc(true)
-	}
-	return n
-}
-
-// importconst declares symbol s as an imported constant with type t and value val.
-// ipkg is the package being imported
-func importconst(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type, val constant.Value) *ir.Name {
-	n := importobj(ipkg, pos, s, ir.OLITERAL, ir.PEXTERN, t)
-	n.SetVal(val)
-	return n
-}
-
-// importfunc declares symbol s as an imported function with type t.
-// ipkg is the package being imported
-func importfunc(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type) *ir.Name {
-	n := importobj(ipkg, pos, s, ir.ONAME, ir.PFUNC, t)
-
-	fn := ir.NewFunc(pos)
-	fn.SetType(t)
-	n.SetFunc(fn)
-	fn.Nname = n
-
-	return n
-}
-
-// importvar declares symbol s as an imported variable with type t.
-// ipkg is the package being imported
-func importvar(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type) *ir.Name {
-	return importobj(ipkg, pos, s, ir.ONAME, ir.PEXTERN, t)
-}
-
-// importalias declares symbol s as an imported type alias with type t.
-// ipkg is the package being imported
-func importalias(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type) *ir.Name {
-	return importobj(ipkg, pos, s, ir.OTYPE, ir.PEXTERN, t)
-}
-
 func dumpasmhdr() {
 	b, err := bio.Create(base.Flag.AsmHdr)
 	if err != nil {
 		base.Fatalf("%v", err)
 	}
 	fmt.Fprintf(b, "// generated by compile -asmhdr from package %s\n\n", types.LocalPkg.Name)
-	for _, n := range Target.Asms {
+	for _, n := range typecheck.Target.Asms {
 		if n.Sym().IsBlank() {
 			continue
 		}
@@ -176,3 +73,83 @@ func dumpasmhdr() {
 
 	b.Close()
 }
+
+type exporter struct {
+	marked map[*types.Type]bool // types already seen by markType
+}
+
+// markObject visits a reachable object.
+func (p *exporter) markObject(n ir.Node) {
+	if n.Op() == ir.ONAME {
+		n := n.(*ir.Name)
+		if n.Class_ == ir.PFUNC {
+			inlFlood(n, typecheck.Export)
+		}
+	}
+
+	p.markType(n.Type())
+}
+
+// markType recursively visits types reachable from t to identify
+// functions whose inline bodies may be needed.
+func (p *exporter) markType(t *types.Type) {
+	if p.marked[t] {
+		return
+	}
+	p.marked[t] = true
+
+	// If this is a named type, mark all of its associated
+	// methods. Skip interface types because t.Methods contains
+	// only their unexpanded method set (i.e., exclusive of
+	// interface embeddings), and the switch statement below
+	// handles their full method set.
+	if t.Sym() != nil && t.Kind() != types.TINTER {
+		for _, m := range t.Methods().Slice() {
+			if types.IsExported(m.Sym.Name) {
+				p.markObject(ir.AsNode(m.Nname))
+			}
+		}
+	}
+
+	// Recursively mark any types that can be produced given a
+	// value of type t: dereferencing a pointer; indexing or
+	// iterating over an array, slice, or map; receiving from a
+	// channel; accessing a struct field or interface method; or
+	// calling a function.
+	//
+	// Notably, we don't mark function parameter types, because
+	// the user already needs some way to construct values of
+	// those types.
+	switch t.Kind() {
+	case types.TPTR, types.TARRAY, types.TSLICE:
+		p.markType(t.Elem())
+
+	case types.TCHAN:
+		if t.ChanDir().CanRecv() {
+			p.markType(t.Elem())
+		}
+
+	case types.TMAP:
+		p.markType(t.Key())
+		p.markType(t.Elem())
+
+	case types.TSTRUCT:
+		for _, f := range t.FieldSlice() {
+			if types.IsExported(f.Sym.Name) || f.Embedded != 0 {
+				p.markType(f.Type)
+			}
+		}
+
+	case types.TFUNC:
+		for _, f := range t.Results().FieldSlice() {
+			p.markType(f.Type)
+		}
+
+	case types.TINTER:
+		for _, f := range t.FieldSlice() {
+			if types.IsExported(f.Sym.Name) {
+				p.markType(f.Type)
+			}
+		}
+	}
+}
diff --git a/src/cmd/compile/internal/gc/gen.go b/src/cmd/compile/internal/gc/gen.go
deleted file mode 100644
index 1084ff883f..0000000000
--- a/src/cmd/compile/internal/gc/gen.go
+++ /dev/null
@@ -1,76 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package gc
-
-import (
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/types"
-	"cmd/internal/obj"
-	"cmd/internal/src"
-	"strconv"
-)
-
-// sysfunc looks up Go function name in package runtime. This function
-// must follow the internal calling convention.
-func sysfunc(name string) *obj.LSym {
-	s := ir.Pkgs.Runtime.Lookup(name)
-	s.SetFunc(true)
-	return s.Linksym()
-}
-
-// sysvar looks up a variable (or assembly function) name in package
-// runtime. If this is a function, it may have a special calling
-// convention.
-func sysvar(name string) *obj.LSym {
-	return ir.Pkgs.Runtime.Lookup(name).Linksym()
-}
-
-// autotmpname returns the name for an autotmp variable numbered n.
-func autotmpname(n int) string {
-	// Give each tmp a different name so that they can be registerized.
-	// Add a preceding . to avoid clashing with legal names.
-	const prefix = ".autotmp_"
-	// Start with a buffer big enough to hold a large n.
-	b := []byte(prefix + "      ")[:len(prefix)]
-	b = strconv.AppendInt(b, int64(n), 10)
-	return types.InternString(b)
-}
-
-// make a new Node off the books
-func tempAt(pos src.XPos, curfn *ir.Func, t *types.Type) *ir.Name {
-	if curfn == nil {
-		base.Fatalf("no curfn for tempAt")
-	}
-	if curfn.Op() == ir.OCLOSURE {
-		ir.Dump("tempAt", curfn)
-		base.Fatalf("adding tempAt to wrong closure function")
-	}
-	if t == nil {
-		base.Fatalf("tempAt called with nil type")
-	}
-
-	s := &types.Sym{
-		Name: autotmpname(len(curfn.Dcl)),
-		Pkg:  types.LocalPkg,
-	}
-	n := ir.NewNameAt(pos, s)
-	s.Def = n
-	n.SetType(t)
-	n.Class_ = ir.PAUTO
-	n.SetEsc(ir.EscNever)
-	n.Curfn = curfn
-	n.SetUsed(true)
-	n.SetAutoTemp(true)
-	curfn.Dcl = append(curfn.Dcl, n)
-
-	types.CalcSize(t)
-
-	return n
-}
-
-func temp(t *types.Type) *ir.Name {
-	return tempAt(base.Pos, ir.CurFunc, t)
-}
diff --git a/src/cmd/compile/internal/gc/go.go b/src/cmd/compile/internal/gc/go.go
index a2587b3361..7648e910d5 100644
--- a/src/cmd/compile/internal/gc/go.go
+++ b/src/cmd/compile/internal/gc/go.go
@@ -5,7 +5,6 @@
 package gc
 
 import (
-	"cmd/compile/internal/ir"
 	"cmd/compile/internal/ssa"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
@@ -14,37 +13,13 @@ import (
 
 var pragcgobuf [][]string
 
-var decldepth int32
-
-var inimport bool // set during import
-
 var zerosize int64
 
-var (
-	okforeq    [types.NTYPE]bool
-	okforadd   [types.NTYPE]bool
-	okforand   [types.NTYPE]bool
-	okfornone  [types.NTYPE]bool
-	okforbool  [types.NTYPE]bool
-	okforcap   [types.NTYPE]bool
-	okforlen   [types.NTYPE]bool
-	okforarith [types.NTYPE]bool
-)
-
-var (
-	okfor [ir.OEND][]bool
-	iscmp [ir.OEND]bool
-)
-
 var (
 	funcsymsmu sync.Mutex // protects funcsyms and associated package lookups (see func funcsym)
 	funcsyms   []*types.Sym
 )
 
-var dclcontext ir.Class // PEXTERN/PAUTO
-
-var typecheckok bool
-
 // interface to back end
 
 type Arch struct {
diff --git a/src/cmd/compile/internal/gc/gsubr.go b/src/cmd/compile/internal/gc/gsubr.go
index 6ea9b354ab..f24687ec0f 100644
--- a/src/cmd/compile/internal/gc/gsubr.go
+++ b/src/cmd/compile/internal/gc/gsubr.go
@@ -34,6 +34,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/ssa"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/objabi"
@@ -196,11 +197,11 @@ func makeABIWrapper(f *ir.Func, wrapperABI obj.ABI) {
 
 	// Q: is this needed?
 	savepos := base.Pos
-	savedclcontext := dclcontext
+	savedclcontext := typecheck.DeclContext
 	savedcurfn := ir.CurFunc
 
 	base.Pos = base.AutogeneratedPos
-	dclcontext = ir.PEXTERN
+	typecheck.DeclContext = ir.PEXTERN
 
 	// At the moment we don't support wrapping a method, we'd need machinery
 	// below to handle the receiver. Panic if we see this scenario.
@@ -213,11 +214,11 @@ func makeABIWrapper(f *ir.Func, wrapperABI obj.ABI) {
 	var noReceiver *ir.Field
 	tfn := ir.NewFuncType(base.Pos,
 		noReceiver,
-		structargs(ft.Params(), true),
-		structargs(ft.Results(), false))
+		typecheck.NewFuncParams(ft.Params(), true),
+		typecheck.NewFuncParams(ft.Results(), false))
 
 	// Reuse f's types.Sym to create a new ODCLFUNC/function.
-	fn := dclfunc(f.Nname.Sym(), tfn)
+	fn := typecheck.DeclFunc(f.Nname.Sym(), tfn)
 	fn.SetDupok(true)
 	fn.SetWrapper(true) // ignore frame for panic+recover matching
 
@@ -281,22 +282,22 @@ func makeABIWrapper(f *ir.Func, wrapperABI obj.ABI) {
 	}
 	fn.Body.Append(tail)
 
-	funcbody()
+	typecheck.FinishFuncBody()
 	if base.Debug.DclStack != 0 {
 		types.CheckDclstack()
 	}
 
-	typecheckFunc(fn)
+	typecheck.Func(fn)
 	ir.CurFunc = fn
-	typecheckslice(fn.Body, ctxStmt)
+	typecheck.Stmts(fn.Body)
 
 	escapeFuncs([]*ir.Func{fn}, false)
 
-	Target.Decls = append(Target.Decls, fn)
+	typecheck.Target.Decls = append(typecheck.Target.Decls, fn)
 
 	// Restore previous context.
 	base.Pos = savepos
-	dclcontext = savedclcontext
+	typecheck.DeclContext = savedclcontext
 	ir.CurFunc = savedcurfn
 }
 
diff --git a/src/cmd/compile/internal/gc/init.go b/src/cmd/compile/internal/gc/init.go
index f22e49efba..ed61c11522 100644
--- a/src/cmd/compile/internal/gc/init.go
+++ b/src/cmd/compile/internal/gc/init.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 )
@@ -17,12 +18,8 @@ import (
 // the name, normally "pkg.init", is altered to "pkg.init.0".
 var renameinitgen int
 
-// Function collecting autotmps generated during typechecking,
-// to be included in the package-level init function.
-var initTodo = ir.NewFunc(base.Pos)
-
 func renameinit() *types.Sym {
-	s := lookupN("init.", renameinitgen)
+	s := typecheck.LookupNum("init.", renameinitgen)
 	renameinitgen++
 	return s
 }
@@ -34,14 +31,14 @@ func renameinit() *types.Sym {
 //   2) Initialize all the variables that have initializers.
 //   3) Run any init functions.
 func fninit() *ir.Name {
-	nf := initOrder(Target.Decls)
+	nf := initOrder(typecheck.Target.Decls)
 
 	var deps []*obj.LSym // initTask records for packages the current package depends on
 	var fns []*obj.LSym  // functions to call for package initialization
 
 	// Find imported packages with init tasks.
-	for _, pkg := range Target.Imports {
-		n := resolve(ir.NewIdent(base.Pos, pkg.Lookup(".inittask")))
+	for _, pkg := range typecheck.Target.Imports {
+		n := typecheck.Resolve(ir.NewIdent(base.Pos, pkg.Lookup(".inittask")))
 		if n.Op() == ir.ONONAME {
 			continue
 		}
@@ -54,34 +51,34 @@ func fninit() *ir.Name {
 	// Make a function that contains all the initialization statements.
 	if len(nf) > 0 {
 		base.Pos = nf[0].Pos() // prolog/epilog gets line number of first init stmt
-		initializers := lookup("init")
-		fn := dclfunc(initializers, ir.NewFuncType(base.Pos, nil, nil, nil))
-		for _, dcl := range initTodo.Dcl {
+		initializers := typecheck.Lookup("init")
+		fn := typecheck.DeclFunc(initializers, ir.NewFuncType(base.Pos, nil, nil, nil))
+		for _, dcl := range typecheck.InitTodoFunc.Dcl {
 			dcl.Curfn = fn
 		}
-		fn.Dcl = append(fn.Dcl, initTodo.Dcl...)
-		initTodo.Dcl = nil
+		fn.Dcl = append(fn.Dcl, typecheck.InitTodoFunc.Dcl...)
+		typecheck.InitTodoFunc.Dcl = nil
 
 		fn.Body.Set(nf)
-		funcbody()
+		typecheck.FinishFuncBody()
 
-		typecheckFunc(fn)
+		typecheck.Func(fn)
 		ir.CurFunc = fn
-		typecheckslice(nf, ctxStmt)
+		typecheck.Stmts(nf)
 		ir.CurFunc = nil
-		Target.Decls = append(Target.Decls, fn)
+		typecheck.Target.Decls = append(typecheck.Target.Decls, fn)
 		fns = append(fns, initializers.Linksym())
 	}
-	if initTodo.Dcl != nil {
+	if typecheck.InitTodoFunc.Dcl != nil {
 		// We only generate temps using initTodo if there
 		// are package-scope initialization statements, so
 		// something's weird if we get here.
 		base.Fatalf("initTodo still has declarations")
 	}
-	initTodo = nil
+	typecheck.InitTodoFunc = nil
 
 	// Record user init functions.
-	for _, fn := range Target.Inits {
+	for _, fn := range typecheck.Target.Inits {
 		// Skip init functions with empty bodies.
 		if len(fn.Body) == 1 {
 			if stmt := fn.Body[0]; stmt.Op() == ir.OBLOCK && len(stmt.(*ir.BlockStmt).List) == 0 {
@@ -96,8 +93,8 @@ func fninit() *ir.Name {
 	}
 
 	// Make an .inittask structure.
-	sym := lookup(".inittask")
-	task := NewName(sym)
+	sym := typecheck.Lookup(".inittask")
+	task := typecheck.NewName(sym)
 	task.SetType(types.Types[types.TUINT8]) // fake type
 	task.Class_ = ir.PEXTERN
 	sym.Def = task
diff --git a/src/cmd/compile/internal/gc/inl.go b/src/cmd/compile/internal/gc/inl.go
index b9e19da43f..9cf23caf0e 100644
--- a/src/cmd/compile/internal/gc/inl.go
+++ b/src/cmd/compile/internal/gc/inl.go
@@ -30,6 +30,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/logopt"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/src"
@@ -54,7 +55,7 @@ const (
 
 func InlinePackage() {
 	// Find functions that can be inlined and clone them before walk expands them.
-	ir.VisitFuncsBottomUp(Target.Decls, func(list []*ir.Func, recursive bool) {
+	ir.VisitFuncsBottomUp(typecheck.Target.Decls, func(list []*ir.Func, recursive bool) {
 		numfns := numNonClosures(list)
 		for _, n := range list {
 			if !recursive || numfns > 1 {
@@ -72,63 +73,6 @@ func InlinePackage() {
 	})
 }
 
-// Get the function's package. For ordinary functions it's on the ->sym, but for imported methods
-// the ->sym can be re-used in the local package, so peel it off the receiver's type.
-func fnpkg(fn *ir.Name) *types.Pkg {
-	if ir.IsMethod(fn) {
-		// method
-		rcvr := fn.Type().Recv().Type
-
-		if rcvr.IsPtr() {
-			rcvr = rcvr.Elem()
-		}
-		if rcvr.Sym() == nil {
-			base.Fatalf("receiver with no sym: [%v] %L  (%v)", fn.Sym(), fn, rcvr)
-		}
-		return rcvr.Sym().Pkg
-	}
-
-	// non-method
-	return fn.Sym().Pkg
-}
-
-// Lazy typechecking of imported bodies. For local functions, caninl will set ->typecheck
-// because they're a copy of an already checked body.
-func typecheckinl(fn *ir.Func) {
-	lno := ir.SetPos(fn.Nname)
-
-	expandInline(fn)
-
-	// typecheckinl is only for imported functions;
-	// their bodies may refer to unsafe as long as the package
-	// was marked safe during import (which was checked then).
-	// the ->inl of a local function has been typechecked before caninl copied it.
-	pkg := fnpkg(fn.Nname)
-
-	if pkg == types.LocalPkg || pkg == nil {
-		return // typecheckinl on local function
-	}
-
-	if base.Flag.LowerM > 2 || base.Debug.Export != 0 {
-		fmt.Printf("typecheck import [%v] %L { %v }\n", fn.Sym(), fn, ir.Nodes(fn.Inl.Body))
-	}
-
-	savefn := ir.CurFunc
-	ir.CurFunc = fn
-	typecheckslice(fn.Inl.Body, ctxStmt)
-	ir.CurFunc = savefn
-
-	// During expandInline (which imports fn.Func.Inl.Body),
-	// declarations are added to fn.Func.Dcl by funcHdr(). Move them
-	// to fn.Func.Inl.Dcl for consistency with how local functions
-	// behave. (Append because typecheckinl may be called multiple
-	// times.)
-	fn.Inl.Dcl = append(fn.Inl.Dcl, fn.Dcl...)
-	fn.Dcl = nil
-
-	base.Pos = lno
-}
-
 // Caninl determines whether fn is inlineable.
 // If so, caninl saves fn->nbody in fn->inl and substitutes it with a copy.
 // fn and ->nbody will already have been typechecked.
@@ -270,7 +214,7 @@ func inlFlood(n *ir.Name, exportsym func(*ir.Name)) {
 	}
 	fn.SetExportInline(true)
 
-	typecheckinl(fn)
+	typecheck.ImportedBody(fn)
 
 	// Recursively identify all referenced functions for
 	// reexport. We want to include even non-called functions,
@@ -601,7 +545,7 @@ func inlnode(n ir.Node, maxCost int32, inlMap map[*ir.Func]bool, edit func(ir.No
 			as.Rhs.Set(inlconv2list(as.Rhs[0].(*ir.InlinedCallExpr)))
 			as.SetOp(ir.OAS2)
 			as.SetTypecheck(0)
-			n = typecheck(as, ctxStmt)
+			n = typecheck.Stmt(as)
 		}
 	}
 
@@ -768,7 +712,7 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 		inlMap[fn] = false
 	}()
 	if base.Debug.TypecheckInl == 0 {
-		typecheckinl(fn)
+		typecheck.ImportedBody(fn)
 	}
 
 	// We have a function node, and it has an inlineable body.
@@ -824,21 +768,21 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 			}
 
 			if v.Byval() {
-				iv := typecheck(inlvar(v), ctxExpr)
+				iv := typecheck.Expr(inlvar(v))
 				ninit.Append(ir.NewDecl(base.Pos, ir.ODCL, iv))
-				ninit.Append(typecheck(ir.NewAssignStmt(base.Pos, iv, o), ctxStmt))
+				ninit.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, iv, o)))
 				inlvars[v] = iv
 			} else {
-				addr := NewName(lookup("&" + v.Sym().Name))
+				addr := typecheck.NewName(typecheck.Lookup("&" + v.Sym().Name))
 				addr.SetType(types.NewPtr(v.Type()))
-				ia := typecheck(inlvar(addr), ctxExpr)
+				ia := typecheck.Expr(inlvar(addr))
 				ninit.Append(ir.NewDecl(base.Pos, ir.ODCL, ia))
-				ninit.Append(typecheck(ir.NewAssignStmt(base.Pos, ia, nodAddr(o)), ctxStmt))
+				ninit.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, ia, typecheck.NodAddr(o))))
 				inlvars[addr] = ia
 
 				// When capturing by reference, all occurrence of the captured var
 				// must be substituted with dereference of the temporary address
-				inlvars[v] = typecheck(ir.NewStarExpr(base.Pos, ia), ctxExpr)
+				inlvars[v] = typecheck.Expr(ir.NewStarExpr(base.Pos, ia))
 			}
 		}
 	}
@@ -857,7 +801,7 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 			// nothing should have moved to the heap yet.
 			base.Fatalf("impossible: %v", ln)
 		}
-		inlf := typecheck(inlvar(ln), ctxExpr)
+		inlf := typecheck.Expr(inlvar(ln))
 		inlvars[ln] = inlf
 		if base.Flag.GenDwarfInl > 0 {
 			if ln.Class_ == ir.PPARAM {
@@ -889,7 +833,7 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 		if n := ir.AsNode(t.Nname); n != nil && !ir.IsBlank(n) && !strings.HasPrefix(n.Sym().Name, "~r") {
 			n := n.(*ir.Name)
 			m = inlvar(n)
-			m = typecheck(m, ctxExpr)
+			m = typecheck.Expr(m)
 			inlvars[n] = m
 			delayretvars = false // found a named result parameter
 		} else {
@@ -951,7 +895,7 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 		vas = ir.NewAssignStmt(base.Pos, nil, nil)
 		vas.X = inlParam(param, vas, inlvars)
 		if len(varargs) == 0 {
-			vas.Y = nodnil()
+			vas.Y = typecheck.NodNil()
 			vas.Y.SetType(param.Type)
 		} else {
 			lit := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(param.Type).(ir.Ntype), nil)
@@ -961,11 +905,11 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 	}
 
 	if len(as.Rhs) != 0 {
-		ninit.Append(typecheck(as, ctxStmt))
+		ninit.Append(typecheck.Stmt(as))
 	}
 
 	if vas != nil {
-		ninit.Append(typecheck(vas, ctxStmt))
+		ninit.Append(typecheck.Stmt(vas))
 	}
 
 	if !delayretvars {
@@ -973,11 +917,11 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 		for _, n := range retvars {
 			ninit.Append(ir.NewDecl(base.Pos, ir.ODCL, n))
 			ras := ir.NewAssignStmt(base.Pos, n, nil)
-			ninit.Append(typecheck(ras, ctxStmt))
+			ninit.Append(typecheck.Stmt(ras))
 		}
 	}
 
-	retlabel := autolabel(".i")
+	retlabel := typecheck.AutoLabel(".i")
 
 	inlgen++
 
@@ -1021,7 +965,7 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b
 	lab := ir.NewLabelStmt(base.Pos, retlabel)
 	body = append(body, lab)
 
-	typecheckslice(body, ctxStmt)
+	typecheck.Stmts(body)
 
 	if base.Flag.GenDwarfInl > 0 {
 		for _, v := range inlfvars {
@@ -1061,7 +1005,7 @@ func inlvar(var_ ir.Node) ir.Node {
 		fmt.Printf("inlvar %+v\n", var_)
 	}
 
-	n := NewName(var_.Sym())
+	n := typecheck.NewName(var_.Sym())
 	n.SetType(var_.Type())
 	n.Class_ = ir.PAUTO
 	n.SetUsed(true)
@@ -1074,7 +1018,7 @@ func inlvar(var_ ir.Node) ir.Node {
 
 // Synthesize a variable to store the inlined function's results in.
 func retvar(t *types.Field, i int) ir.Node {
-	n := NewName(lookupN("~R", i))
+	n := typecheck.NewName(typecheck.LookupNum("~R", i))
 	n.SetType(t.Type)
 	n.Class_ = ir.PAUTO
 	n.SetUsed(true)
@@ -1086,7 +1030,7 @@ func retvar(t *types.Field, i int) ir.Node {
 // Synthesize a variable to store the inlined function's arguments
 // when they come from a multiple return call.
 func argvar(t *types.Type, i int) ir.Node {
-	n := NewName(lookupN("~arg", i))
+	n := typecheck.NewName(typecheck.LookupNum("~arg", i))
 	n.SetType(t.Elem())
 	n.Class_ = ir.PAUTO
 	n.SetUsed(true)
@@ -1198,10 +1142,10 @@ func (subst *inlsubst) node(n ir.Node) ir.Node {
 				}
 			}
 
-			init = append(init, typecheck(as, ctxStmt))
+			init = append(init, typecheck.Stmt(as))
 		}
 		init = append(init, ir.NewBranchStmt(base.Pos, ir.OGOTO, subst.retlabel))
-		typecheckslice(init, ctxStmt)
+		typecheck.Stmts(init)
 		return ir.NewBlockStmt(base.Pos, init)
 
 	case ir.OGOTO:
@@ -1210,7 +1154,7 @@ func (subst *inlsubst) node(n ir.Node) ir.Node {
 		m.SetPos(subst.updatedPos(m.Pos()))
 		m.PtrInit().Set(nil)
 		p := fmt.Sprintf("%s·%d", n.Label.Name, inlgen)
-		m.Label = lookup(p)
+		m.Label = typecheck.Lookup(p)
 		return m
 
 	case ir.OLABEL:
@@ -1219,7 +1163,7 @@ func (subst *inlsubst) node(n ir.Node) ir.Node {
 		m.SetPos(subst.updatedPos(m.Pos()))
 		m.PtrInit().Set(nil)
 		p := fmt.Sprintf("%s·%d", n.Label.Name, inlgen)
-		m.Label = lookup(p)
+		m.Label = typecheck.Lookup(p)
 		return m
 	}
 
@@ -1284,7 +1228,7 @@ func devirtualizeCall(call *ir.CallExpr) {
 
 	dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, nil)
 	dt.SetType(typ)
-	x := typecheck(ir.NewSelectorExpr(sel.Pos(), ir.OXDOT, dt, sel.Sel), ctxExpr|ctxCallee)
+	x := typecheck.Callee(ir.NewSelectorExpr(sel.Pos(), ir.OXDOT, dt, sel.Sel))
 	switch x.Op() {
 	case ir.ODOTMETH:
 		x := x.(*ir.SelectorExpr)
diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index 69ec5c8f2f..b98d1f2e10 100644
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -13,6 +13,7 @@ import (
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/logopt"
 	"cmd/compile/internal/ssa"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/bio"
 	"cmd/internal/dwarf"
@@ -49,9 +50,6 @@ func hidePanic() {
 	}
 }
 
-// Target is the package being compiled.
-var Target *ir.Package
-
 // Main parses flags and Go source files specified in the command-line
 // arguments, type-checks the parsed Go package, compiles functions to machine
 // code, and finally writes the compiled package definition to disk.
@@ -197,18 +195,18 @@ func Main(archInit func(*Arch)) {
 		return typenamesym(t).Linksym()
 	}
 
-	Target = new(ir.Package)
+	typecheck.Target = new(ir.Package)
 
-	NeedFuncSym = makefuncsym
-	NeedITab = func(t, iface *types.Type) { itabname(t, iface) }
-	NeedRuntimeType = addsignat // TODO(rsc): typenamesym for lock?
+	typecheck.NeedFuncSym = makefuncsym
+	typecheck.NeedITab = func(t, iface *types.Type) { itabname(t, iface) }
+	typecheck.NeedRuntimeType = addsignat // TODO(rsc): typenamesym for lock?
 
 	base.AutogeneratedPos = makePos(src.NewFileBase("<autogenerated>", "<autogenerated>"), 1, 0)
 
 	types.TypeLinkSym = func(t *types.Type) *obj.LSym {
 		return typenamesym(t).Linksym()
 	}
-	TypecheckInit()
+	typecheck.Init()
 
 	// Parse input.
 	base.Timer.Start("fe", "parse")
@@ -219,7 +217,7 @@ func Main(archInit func(*Arch)) {
 	recordPackageName()
 
 	// Typecheck.
-	TypecheckPackage()
+	typecheck.Package()
 
 	// With all user code typechecked, it's now safe to verify unused dot imports.
 	checkDotImports()
@@ -227,7 +225,7 @@ func Main(archInit func(*Arch)) {
 
 	// Build init task.
 	if initTask := fninit(); initTask != nil {
-		exportsym(initTask)
+		typecheck.Export(initTask)
 	}
 
 	// Inlining
@@ -237,7 +235,7 @@ func Main(archInit func(*Arch)) {
 	}
 
 	// Devirtualize.
-	for _, n := range Target.Decls {
+	for _, n := range typecheck.Target.Decls {
 		if n.Op() == ir.ODCLFUNC {
 			devirtualize(n.(*ir.Func))
 		}
@@ -253,7 +251,7 @@ func Main(archInit func(*Arch)) {
 	// Large values are also moved off stack in escape analysis;
 	// because large values may contain pointers, it must happen early.
 	base.Timer.Start("fe", "escapes")
-	escapes(Target.Decls)
+	escapes(typecheck.Target.Decls)
 
 	// Collect information for go:nowritebarrierrec
 	// checking. This must happen before transformclosure.
@@ -267,7 +265,7 @@ func Main(archInit func(*Arch)) {
 	// This needs to happen before walk, because closures must be transformed
 	// before walk reaches a call of a closure.
 	base.Timer.Start("fe", "xclosures")
-	for _, n := range Target.Decls {
+	for _, n := range typecheck.Target.Decls {
 		if n.Op() == ir.ODCLFUNC {
 			n := n.(*ir.Func)
 			if n.OClosure != nil {
@@ -292,8 +290,8 @@ func Main(archInit func(*Arch)) {
 	// Don't use range--walk can add functions to Target.Decls.
 	base.Timer.Start("be", "compilefuncs")
 	fcount := int64(0)
-	for i := 0; i < len(Target.Decls); i++ {
-		n := Target.Decls[i]
+	for i := 0; i < len(typecheck.Target.Decls); i++ {
+		n := typecheck.Target.Decls[i]
 		if n.Op() == ir.ODCLFUNC {
 			funccompile(n.(*ir.Func))
 			fcount++
@@ -327,7 +325,7 @@ func Main(archInit func(*Arch)) {
 	}
 
 	CheckLargeStacks()
-	CheckFuncStack()
+	typecheck.CheckFuncStack()
 
 	if len(compilequeue) != 0 {
 		base.Fatalf("%d uncompiled functions", len(compilequeue))
@@ -363,7 +361,7 @@ func CheckLargeStacks() {
 func cgoSymABIs() {
 	// The linker expects an ABI0 wrapper for all cgo-exported
 	// functions.
-	for _, prag := range Target.CgoPragmas {
+	for _, prag := range typecheck.Target.CgoPragmas {
 		switch prag[0] {
 		case "cgo_export_static", "cgo_export_dynamic":
 			if symabiRefs == nil {
@@ -581,33 +579,6 @@ func findpkg(name string) (file string, ok bool) {
 	return "", false
 }
 
-// loadsys loads the definitions for the low-level runtime functions,
-// so that the compiler can generate calls to them,
-// but does not make them visible to user code.
-func loadsys() {
-	types.Block = 1
-
-	inimport = true
-	typecheckok = true
-
-	typs := runtimeTypes()
-	for _, d := range &runtimeDecls {
-		sym := ir.Pkgs.Runtime.Lookup(d.name)
-		typ := typs[d.typ]
-		switch d.tag {
-		case funcTag:
-			importfunc(ir.Pkgs.Runtime, src.NoXPos, sym, typ)
-		case varTag:
-			importvar(ir.Pkgs.Runtime, src.NoXPos, sym, typ)
-		default:
-			base.Fatalf("unhandled declaration tag %v", d.tag)
-		}
-	}
-
-	typecheckok = false
-	inimport = false
-}
-
 // myheight tracks the local package's height based on packages
 // imported so far.
 var myheight int
@@ -776,7 +747,7 @@ func importfile(f constant.Value) *types.Pkg {
 			base.Errorf("import %s: unexpected package format byte: %v", file, c)
 			base.ErrorExit()
 		}
-		fingerprint = iimport(importpkg, imp)
+		fingerprint = typecheck.ReadImports(importpkg, imp)
 
 	default:
 		base.Errorf("no import in %q", path_)
diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go
index c83b60dcd4..3e8703f050 100644
--- a/src/cmd/compile/internal/gc/noder.go
+++ b/src/cmd/compile/internal/gc/noder.go
@@ -19,6 +19,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/syntax"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/objabi"
 	"cmd/internal/src"
@@ -160,7 +161,7 @@ type noder struct {
 func (p *noder) funcBody(fn *ir.Func, block *syntax.BlockStmt) {
 	oldScope := p.scope
 	p.scope = 0
-	funchdr(fn)
+	typecheck.StartFuncBody(fn)
 
 	if block != nil {
 		body := p.stmts(block.List)
@@ -173,7 +174,7 @@ func (p *noder) funcBody(fn *ir.Func, block *syntax.BlockStmt) {
 		fn.Endlineno = base.Pos
 	}
 
-	funcbody()
+	typecheck.FinishFuncBody()
 	p.scope = oldScope
 }
 
@@ -261,7 +262,7 @@ func (p *noder) node() {
 		p.checkUnused(pragma)
 	}
 
-	Target.Decls = append(Target.Decls, p.decls(p.file.DeclList)...)
+	typecheck.Target.Decls = append(typecheck.Target.Decls, p.decls(p.file.DeclList)...)
 
 	base.Pos = src.NoXPos
 	clearImports()
@@ -273,7 +274,7 @@ func (p *noder) processPragmas() {
 			p.errorAt(l.pos, "//go:linkname only allowed in Go files that import \"unsafe\"")
 			continue
 		}
-		n := ir.AsNode(lookup(l.local).Def)
+		n := ir.AsNode(typecheck.Lookup(l.local).Def)
 		if n == nil || n.Op() != ir.ONAME {
 			// TODO(mdempsky): Change to p.errorAt before Go 1.17 release.
 			// base.WarnfAt(p.makeXPos(l.pos), "//go:linkname must refer to declared function or variable (will be an error in Go 1.17)")
@@ -285,7 +286,7 @@ func (p *noder) processPragmas() {
 		}
 		n.Sym().Linkname = l.remote
 	}
-	Target.CgoPragmas = append(Target.CgoPragmas, p.pragcgobuf...)
+	typecheck.Target.CgoPragmas = append(typecheck.Target.CgoPragmas, p.pragcgobuf...)
 }
 
 func (p *noder) decls(decls []syntax.Decl) (l []ir.Node) {
@@ -342,7 +343,7 @@ func (p *noder) importDecl(imp *syntax.ImportDecl) {
 	}
 
 	if !ipkg.Direct {
-		Target.Imports = append(Target.Imports, ipkg)
+		typecheck.Target.Imports = append(typecheck.Target.Imports, ipkg)
 	}
 	ipkg.Direct = true
 
@@ -350,7 +351,7 @@ func (p *noder) importDecl(imp *syntax.ImportDecl) {
 	if imp.LocalPkgName != nil {
 		my = p.name(imp.LocalPkgName)
 	} else {
-		my = lookup(ipkg.Name)
+		my = typecheck.Lookup(ipkg.Name)
 	}
 
 	pack := ir.NewPkgName(p.pos(imp), my, ipkg)
@@ -366,7 +367,7 @@ func (p *noder) importDecl(imp *syntax.ImportDecl) {
 		return
 	}
 	if my.Def != nil {
-		redeclare(pack.Pos(), my, "as imported package name")
+		typecheck.Redeclared(pack.Pos(), my, "as imported package name")
 	}
 	my.Def = pack
 	my.Lastlineno = pack.Pos()
@@ -401,7 +402,7 @@ func (p *noder) varDecl(decl *syntax.VarDecl) []ir.Node {
 	}
 
 	p.setlineno(decl)
-	return variter(names, typ, exprs)
+	return typecheck.DeclVars(names, typ, exprs)
 }
 
 // constState tracks state between constant specifiers within a
@@ -449,7 +450,7 @@ func (p *noder) constDecl(decl *syntax.ConstDecl, cs *constState) []ir.Node {
 		if decl.Values == nil {
 			v = ir.DeepCopy(n.Pos(), v)
 		}
-		declare(n, dclcontext)
+		typecheck.Declare(n, typecheck.DeclContext)
 
 		n.Ntype = typ
 		n.Defn = v
@@ -469,7 +470,7 @@ func (p *noder) constDecl(decl *syntax.ConstDecl, cs *constState) []ir.Node {
 
 func (p *noder) typeDecl(decl *syntax.TypeDecl) ir.Node {
 	n := p.declName(ir.OTYPE, decl.Name)
-	declare(n, dclcontext)
+	typecheck.Declare(n, typecheck.DeclContext)
 
 	// decl.Type may be nil but in that case we got a syntax error during parsing
 	typ := p.typeExprOrNil(decl.Type)
@@ -514,7 +515,7 @@ func (p *noder) funcDecl(fun *syntax.FuncDecl) ir.Node {
 			if len(t.Params) > 0 || len(t.Results) > 0 {
 				base.ErrorfAt(f.Pos(), "func init must have no arguments and no return values")
 			}
-			Target.Inits = append(Target.Inits, f)
+			typecheck.Target.Inits = append(typecheck.Target.Inits, f)
 		}
 
 		if types.LocalPkg.Name == "main" && name.Name == "main" {
@@ -541,7 +542,7 @@ func (p *noder) funcDecl(fun *syntax.FuncDecl) ir.Node {
 	}
 
 	if fun.Recv == nil {
-		declare(f.Nname, ir.PFUNC)
+		typecheck.Declare(f.Nname, ir.PFUNC)
 	}
 
 	p.funcBody(f, fun.Body)
@@ -704,7 +705,7 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 			pos, op := p.pos(expr), p.unOp(expr.Op)
 			switch op {
 			case ir.OADDR:
-				return nodAddrAt(pos, x)
+				return typecheck.NodAddrAt(pos, x)
 			case ir.ODEREF:
 				return ir.NewStarExpr(pos, x)
 			}
@@ -950,7 +951,7 @@ func (p *noder) embedded(typ syntax.Expr) *ir.Field {
 	}
 
 	sym := p.packname(typ)
-	n := ir.NewField(p.pos(typ), lookup(sym.Name), importName(sym).(ir.Ntype), nil)
+	n := ir.NewField(p.pos(typ), typecheck.Lookup(sym.Name), importName(sym).(ir.Ntype), nil)
 	n.Embedded = true
 
 	if isStar {
@@ -1136,8 +1137,8 @@ func (p *noder) assignList(expr syntax.Expr, defn ir.Node, colas bool) []ir.Node
 		}
 
 		newOrErr = true
-		n := NewName(sym)
-		declare(n, dclcontext)
+		n := typecheck.NewName(sym)
+		typecheck.Declare(n, typecheck.DeclContext)
 		n.Defn = defn
 		defn.PtrInit().Append(ir.NewDecl(base.Pos, ir.ODCL, n))
 		res[i] = n
@@ -1245,8 +1246,8 @@ func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitch
 			n.List.Set(p.exprList(clause.Cases))
 		}
 		if tswitch != nil && tswitch.Tag != nil {
-			nn := NewName(tswitch.Tag.Sym())
-			declare(nn, dclcontext)
+			nn := typecheck.NewName(tswitch.Tag.Sym())
+			typecheck.Declare(nn, typecheck.DeclContext)
 			n.Vars = []ir.Node{nn}
 			// keep track of the instances for reporting unused
 			nn.Defn = tswitch
@@ -1466,7 +1467,7 @@ var tokenForLitKind = [...]token.Token{
 }
 
 func (p *noder) name(name *syntax.Name) *types.Sym {
-	return lookup(name.Value)
+	return typecheck.Lookup(name.Value)
 }
 
 func (p *noder) mkname(name *syntax.Name) ir.Node {
diff --git a/src/cmd/compile/internal/gc/obj.go b/src/cmd/compile/internal/gc/obj.go
index 372277552f..1b4ba50e6b 100644
--- a/src/cmd/compile/internal/gc/obj.go
+++ b/src/cmd/compile/internal/gc/obj.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/bio"
 	"cmd/internal/obj"
@@ -117,14 +118,14 @@ func dumpCompilerObj(bout *bio.Writer) {
 }
 
 func dumpdata() {
-	numExterns := len(Target.Externs)
-	numDecls := len(Target.Decls)
+	numExterns := len(typecheck.Target.Externs)
+	numDecls := len(typecheck.Target.Decls)
 
-	dumpglobls(Target.Externs)
+	dumpglobls(typecheck.Target.Externs)
 	dumpfuncsyms()
 	addptabs()
-	numExports := len(Target.Exports)
-	addsignats(Target.Externs)
+	numExports := len(typecheck.Target.Exports)
+	addsignats(typecheck.Target.Externs)
 	dumpsignats()
 	dumptabs()
 	numPTabs, numITabs := CountTabs()
@@ -140,22 +141,22 @@ func dumpdata() {
 	// In the typical case, we loop 0 or 1 times.
 	// It was not until issue 24761 that we found any code that required a loop at all.
 	for {
-		for i := numDecls; i < len(Target.Decls); i++ {
-			n := Target.Decls[i]
+		for i := numDecls; i < len(typecheck.Target.Decls); i++ {
+			n := typecheck.Target.Decls[i]
 			if n.Op() == ir.ODCLFUNC {
 				funccompile(n.(*ir.Func))
 			}
 		}
-		numDecls = len(Target.Decls)
+		numDecls = len(typecheck.Target.Decls)
 		compileFunctions()
 		dumpsignats()
-		if numDecls == len(Target.Decls) {
+		if numDecls == len(typecheck.Target.Decls) {
 			break
 		}
 	}
 
 	// Dump extra globals.
-	dumpglobls(Target.Externs[numExterns:])
+	dumpglobls(typecheck.Target.Externs[numExterns:])
 
 	if zerosize > 0 {
 		zero := ir.Pkgs.Map.Lookup("zero")
@@ -164,7 +165,7 @@ func dumpdata() {
 
 	addGCLocals()
 
-	if numExports != len(Target.Exports) {
+	if numExports != len(typecheck.Target.Exports) {
 		base.Fatalf("Target.Exports changed after compile functions loop")
 	}
 	newNumPTabs, newNumITabs := CountTabs()
@@ -179,11 +180,11 @@ func dumpdata() {
 func dumpLinkerObj(bout *bio.Writer) {
 	printObjHeader(bout)
 
-	if len(Target.CgoPragmas) != 0 {
+	if len(typecheck.Target.CgoPragmas) != 0 {
 		// write empty export section; must be before cgo section
 		fmt.Fprintf(bout, "\n$$\n\n$$\n\n")
 		fmt.Fprintf(bout, "\n$$  // cgo\n")
-		if err := json.NewEncoder(bout).Encode(Target.CgoPragmas); err != nil {
+		if err := json.NewEncoder(bout).Encode(typecheck.Target.CgoPragmas); err != nil {
 			base.Fatalf("serializing pragcgobuf: %v", err)
 		}
 		fmt.Fprintf(bout, "\n$$\n\n")
@@ -198,7 +199,7 @@ func addptabs() {
 	if !base.Ctxt.Flag_dynlink || types.LocalPkg.Name != "main" {
 		return
 	}
-	for _, exportn := range Target.Exports {
+	for _, exportn := range typecheck.Target.Exports {
 		s := exportn.Sym()
 		nn := ir.AsNode(s.Def)
 		if nn == nil {
@@ -474,7 +475,7 @@ func slicedata(pos src.XPos, s string) *ir.Name {
 	slicedataGen++
 	symname := fmt.Sprintf(".gobytes.%d", slicedataGen)
 	sym := types.LocalPkg.Lookup(symname)
-	symnode := NewName(sym)
+	symnode := typecheck.NewName(sym)
 	sym.Def = symnode
 
 	lsym := sym.Linksym()
diff --git a/src/cmd/compile/internal/gc/order.go b/src/cmd/compile/internal/gc/order.go
index 3d35094a58..075bcea92c 100644
--- a/src/cmd/compile/internal/gc/order.go
+++ b/src/cmd/compile/internal/gc/order.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
 	"fmt"
@@ -63,7 +64,7 @@ func order(fn *ir.Func) {
 
 // append typechecks stmt and appends it to out.
 func (o *Order) append(stmt ir.Node) {
-	o.out = append(o.out, typecheck(stmt, ctxStmt))
+	o.out = append(o.out, typecheck.Stmt(stmt))
 }
 
 // newTemp allocates a new temporary with the given type,
@@ -85,7 +86,7 @@ func (o *Order) newTemp(t *types.Type, clear bool) *ir.Name {
 		}
 	}
 	if v == nil {
-		v = temp(t)
+		v = typecheck.Temp(t)
 	}
 	if clear {
 		o.append(ir.NewAssignStmt(base.Pos, v, nil))
@@ -142,7 +143,7 @@ func (o *Order) cheapExpr(n ir.Node) ir.Node {
 		}
 		a := ir.SepCopy(n).(*ir.UnaryExpr)
 		a.X = l
-		return typecheck(a, ctxExpr)
+		return typecheck.Expr(a)
 	}
 
 	return o.copyExpr(n)
@@ -168,7 +169,7 @@ func (o *Order) safeExpr(n ir.Node) ir.Node {
 		}
 		a := ir.SepCopy(n).(*ir.UnaryExpr)
 		a.X = l
-		return typecheck(a, ctxExpr)
+		return typecheck.Expr(a)
 
 	case ir.ODOT:
 		n := n.(*ir.SelectorExpr)
@@ -178,7 +179,7 @@ func (o *Order) safeExpr(n ir.Node) ir.Node {
 		}
 		a := ir.SepCopy(n).(*ir.SelectorExpr)
 		a.X = l
-		return typecheck(a, ctxExpr)
+		return typecheck.Expr(a)
 
 	case ir.ODOTPTR:
 		n := n.(*ir.SelectorExpr)
@@ -188,7 +189,7 @@ func (o *Order) safeExpr(n ir.Node) ir.Node {
 		}
 		a := ir.SepCopy(n).(*ir.SelectorExpr)
 		a.X = l
-		return typecheck(a, ctxExpr)
+		return typecheck.Expr(a)
 
 	case ir.ODEREF:
 		n := n.(*ir.StarExpr)
@@ -198,7 +199,7 @@ func (o *Order) safeExpr(n ir.Node) ir.Node {
 		}
 		a := ir.SepCopy(n).(*ir.StarExpr)
 		a.X = l
-		return typecheck(a, ctxExpr)
+		return typecheck.Expr(a)
 
 	case ir.OINDEX, ir.OINDEXMAP:
 		n := n.(*ir.IndexExpr)
@@ -215,7 +216,7 @@ func (o *Order) safeExpr(n ir.Node) ir.Node {
 		a := ir.SepCopy(n).(*ir.IndexExpr)
 		a.X = l
 		a.Index = r
-		return typecheck(a, ctxExpr)
+		return typecheck.Expr(a)
 
 	default:
 		base.Fatalf("order.safeExpr %v", n.Op())
@@ -241,7 +242,7 @@ func isaddrokay(n ir.Node) bool {
 func (o *Order) addrTemp(n ir.Node) ir.Node {
 	if n.Op() == ir.OLITERAL || n.Op() == ir.ONIL {
 		// TODO: expand this to all static composite literal nodes?
-		n = defaultlit(n, nil)
+		n = typecheck.DefaultLit(n, nil)
 		types.CalcSize(n.Type())
 		vstat := readonlystaticname(n.Type())
 		var s InitSchedule
@@ -249,7 +250,7 @@ func (o *Order) addrTemp(n ir.Node) ir.Node {
 		if s.out != nil {
 			base.Fatalf("staticassign of const generated code: %+v", n)
 		}
-		vstat = typecheck(vstat, ctxExpr).(*ir.Name)
+		vstat = typecheck.Expr(vstat).(*ir.Name)
 		return vstat
 	}
 	if isaddrokay(n) {
@@ -336,7 +337,7 @@ func (o *Order) cleanTempNoPop(mark ordermarker) []ir.Node {
 	var out []ir.Node
 	for i := len(o.temp) - 1; i >= int(mark); i-- {
 		n := o.temp[i]
-		out = append(out, typecheck(ir.NewUnaryExpr(base.Pos, ir.OVARKILL, n), ctxStmt))
+		out = append(out, typecheck.Stmt(ir.NewUnaryExpr(base.Pos, ir.OVARKILL, n)))
 	}
 	return out
 }
@@ -388,7 +389,7 @@ func orderMakeSliceCopy(s []ir.Node) {
 	mk.Cap = cp.Y
 	// Set bounded when m = OMAKESLICE([]T, len(s)); OCOPY(m, s)
 	mk.SetBounded(mk.Len.Op() == ir.OLEN && ir.SameSafeExpr(mk.Len.(*ir.UnaryExpr).X, cp.Y))
-	as.Y = typecheck(mk, ctxExpr)
+	as.Y = typecheck.Expr(mk)
 	s[1] = nil // remove separate copy call
 }
 
@@ -495,7 +496,7 @@ func (o *Order) call(nn ir.Node) {
 	}
 
 	n := nn.(*ir.CallExpr)
-	fixVariadicCall(n)
+	typecheck.FixVariadicCall(n)
 	n.X = o.expr(n.X, nil)
 	o.exprList(n.Args)
 
@@ -513,7 +514,7 @@ func (o *Order) call(nn ir.Node) {
 				x := o.copyExpr(arg.X)
 				arg.X = x
 				x.Name().SetAddrtaken(true) // ensure SSA keeps the x variable
-				n.Body.Append(typecheck(ir.NewUnaryExpr(base.Pos, ir.OVARLIVE, x), ctxStmt))
+				n.Body.Append(typecheck.Stmt(ir.NewUnaryExpr(base.Pos, ir.OVARLIVE, x)))
 			}
 		}
 	}
@@ -584,7 +585,7 @@ func (o *Order) mapAssign(n ir.Node) {
 				t := o.newTemp(m.Type(), false)
 				n.Lhs[i] = t
 				a := ir.NewAssignStmt(base.Pos, m, t)
-				post = append(post, typecheck(a, ctxStmt))
+				post = append(post, typecheck.Stmt(a))
 			}
 		}
 
@@ -653,8 +654,8 @@ func (o *Order) stmt(n ir.Node) {
 				l2.Assigned = false
 			}
 			l2 = o.copyExpr(l2)
-			r := o.expr(typecheck(ir.NewBinaryExpr(n.Pos(), n.AsOp, l2, n.Y), ctxExpr), nil)
-			as := typecheck(ir.NewAssignStmt(n.Pos(), l1, r), ctxStmt)
+			r := o.expr(typecheck.Expr(ir.NewBinaryExpr(n.Pos(), n.AsOp, l2, n.Y)), nil)
+			as := typecheck.Stmt(ir.NewAssignStmt(n.Pos(), l1, r))
 			o.mapAssign(as)
 			o.cleanTemp(t)
 			return
@@ -858,7 +859,7 @@ func (o *Order) stmt(n ir.Node) {
 			if r.Type().IsString() && r.Type() != types.Types[types.TSTRING] {
 				r = ir.NewConvExpr(base.Pos, ir.OCONV, nil, r)
 				r.SetType(types.Types[types.TSTRING])
-				r = typecheck(r, ctxExpr)
+				r = typecheck.Expr(r)
 			}
 
 			n.X = o.copyExpr(r)
@@ -949,11 +950,11 @@ func (o *Order) stmt(n ir.Node) {
 						if len(init) > 0 && init[0].Op() == ir.ODCL && init[0].(*ir.Decl).X == n {
 							init = init[1:]
 						}
-						dcl := typecheck(ir.NewDecl(base.Pos, ir.ODCL, n), ctxStmt)
+						dcl := typecheck.Stmt(ir.NewDecl(base.Pos, ir.ODCL, n))
 						ncas.PtrInit().Append(dcl)
 					}
 					tmp := o.newTemp(t, t.HasPointers())
-					as := typecheck(ir.NewAssignStmt(base.Pos, n, conv(tmp, n.Type())), ctxStmt)
+					as := typecheck.Stmt(ir.NewAssignStmt(base.Pos, n, typecheck.Conv(tmp, n.Type())))
 					ncas.PtrInit().Append(as)
 					r.Lhs[i] = tmp
 				}
@@ -1217,7 +1218,7 @@ func (o *Order) expr1(n, lhs ir.Node) ir.Node {
 
 		// Evaluate left-hand side.
 		lhs := o.expr(n.X, nil)
-		o.out = append(o.out, typecheck(ir.NewAssignStmt(base.Pos, r, lhs), ctxStmt))
+		o.out = append(o.out, typecheck.Stmt(ir.NewAssignStmt(base.Pos, r, lhs)))
 
 		// Evaluate right-hand side, save generated code.
 		saveout := o.out
@@ -1225,7 +1226,7 @@ func (o *Order) expr1(n, lhs ir.Node) ir.Node {
 		t := o.markTemp()
 		o.edge()
 		rhs := o.expr(n.Y, nil)
-		o.out = append(o.out, typecheck(ir.NewAssignStmt(base.Pos, r, rhs), ctxStmt))
+		o.out = append(o.out, typecheck.Stmt(ir.NewAssignStmt(base.Pos, r, rhs)))
 		o.cleanTemp(t)
 		gen := o.out
 		o.out = saveout
@@ -1307,7 +1308,7 @@ func (o *Order) expr1(n, lhs ir.Node) ir.Node {
 	case ir.OCLOSURE:
 		n := n.(*ir.ClosureExpr)
 		if n.Transient() && len(n.Func.ClosureVars) > 0 {
-			n.Prealloc = o.newTemp(closureType(n), false)
+			n.Prealloc = o.newTemp(typecheck.ClosureType(n), false)
 		}
 		return n
 
@@ -1315,7 +1316,7 @@ func (o *Order) expr1(n, lhs ir.Node) ir.Node {
 		n := n.(*ir.CallPartExpr)
 		n.X = o.expr(n.X, nil)
 		if n.Transient() {
-			t := partialCallType(n)
+			t := typecheck.PartialCallType(n)
 			n.Prealloc = o.newTemp(t, false)
 		}
 		return n
@@ -1415,13 +1416,13 @@ func (o *Order) expr1(n, lhs ir.Node) ir.Node {
 		// Emit the creation of the map (with all its static entries).
 		m := o.newTemp(n.Type(), false)
 		as := ir.NewAssignStmt(base.Pos, m, n)
-		typecheck(as, ctxStmt)
+		typecheck.Stmt(as)
 		o.stmt(as)
 
 		// Emit eval+insert of dynamic entries, one at a time.
 		for _, r := range dynamics {
 			as := ir.NewAssignStmt(base.Pos, ir.NewIndexExpr(base.Pos, m, r.Key), r.Value)
-			typecheck(as, ctxStmt) // Note: this converts the OINDEX to an OINDEXMAP
+			typecheck.Stmt(as) // Note: this converts the OINDEX to an OINDEXMAP
 			o.stmt(as)
 		}
 		return m
@@ -1455,7 +1456,7 @@ func (o *Order) as2(n *ir.AssignListStmt) {
 	as := ir.NewAssignListStmt(base.Pos, ir.OAS2, nil, nil)
 	as.Lhs.Set(left)
 	as.Rhs.Set(tmplist)
-	o.stmt(typecheck(as, ctxStmt))
+	o.stmt(typecheck.Stmt(as))
 }
 
 // okAs2 orders OAS2XXX with ok.
@@ -1475,12 +1476,12 @@ func (o *Order) okAs2(n *ir.AssignListStmt) {
 
 	if tmp1 != nil {
 		r := ir.NewAssignStmt(base.Pos, n.Lhs[0], tmp1)
-		o.mapAssign(typecheck(r, ctxStmt))
+		o.mapAssign(typecheck.Stmt(r))
 		n.Lhs[0] = tmp1
 	}
 	if tmp2 != nil {
-		r := ir.NewAssignStmt(base.Pos, n.Lhs[1], conv(tmp2, n.Lhs[1].Type()))
-		o.mapAssign(typecheck(r, ctxStmt))
+		r := ir.NewAssignStmt(base.Pos, n.Lhs[1], typecheck.Conv(tmp2, n.Lhs[1].Type()))
+		o.mapAssign(typecheck.Stmt(r))
 		n.Lhs[1] = tmp2
 	}
 }
diff --git a/src/cmd/compile/internal/gc/pgen.go b/src/cmd/compile/internal/gc/pgen.go
index 337556ea41..c0f3326454 100644
--- a/src/cmd/compile/internal/gc/pgen.go
+++ b/src/cmd/compile/internal/gc/pgen.go
@@ -8,6 +8,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/ssa"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/dwarf"
 	"cmd/internal/obj"
@@ -146,7 +147,7 @@ func (s *ssafn) AllocFrame(f *ssa.Func) {
 	}
 
 	if f.Config.NeedsFpScratch && scratchUsed {
-		s.scratchFpMem = tempAt(src.NoXPos, s.curfn, types.Types[types.TUINT64])
+		s.scratchFpMem = typecheck.TempAt(src.NoXPos, s.curfn, types.Types[types.TUINT64])
 	}
 
 	sort.Sort(byStackVar(fn.Dcl))
@@ -214,11 +215,11 @@ func funccompile(fn *ir.Func) {
 		return
 	}
 
-	dclcontext = ir.PAUTO
+	typecheck.DeclContext = ir.PAUTO
 	ir.CurFunc = fn
 	compile(fn)
 	ir.CurFunc = nil
-	dclcontext = ir.PEXTERN
+	typecheck.DeclContext = ir.PEXTERN
 }
 
 func compile(fn *ir.Func) {
diff --git a/src/cmd/compile/internal/gc/pgen_test.go b/src/cmd/compile/internal/gc/pgen_test.go
index 1170db2681..95c4b24fa1 100644
--- a/src/cmd/compile/internal/gc/pgen_test.go
+++ b/src/cmd/compile/internal/gc/pgen_test.go
@@ -6,6 +6,7 @@ package gc
 
 import (
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
 	"reflect"
@@ -41,7 +42,7 @@ func TestCmpstackvar(t *testing.T) {
 		if s == nil {
 			s = &types.Sym{Name: "."}
 		}
-		n := NewName(s)
+		n := typecheck.NewName(s)
 		n.SetType(t)
 		n.SetFrameOffset(xoffset)
 		n.Class_ = cl
@@ -156,7 +157,7 @@ func TestCmpstackvar(t *testing.T) {
 
 func TestStackvarSort(t *testing.T) {
 	nod := func(xoffset int64, t *types.Type, s *types.Sym, cl ir.Class) *ir.Name {
-		n := NewName(s)
+		n := typecheck.NewName(s)
 		n.SetType(t)
 		n.SetFrameOffset(xoffset)
 		n.Class_ = cl
diff --git a/src/cmd/compile/internal/gc/range.go b/src/cmd/compile/internal/gc/range.go
index a9447189c2..c040811932 100644
--- a/src/cmd/compile/internal/gc/range.go
+++ b/src/cmd/compile/internal/gc/range.go
@@ -7,136 +7,12 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/sys"
 	"unicode/utf8"
 )
 
-// range
-func typecheckrange(n *ir.RangeStmt) {
-	// Typechecking order is important here:
-	// 0. first typecheck range expression (slice/map/chan),
-	//	it is evaluated only once and so logically it is not part of the loop.
-	// 1. typecheck produced values,
-	//	this part can declare new vars and so it must be typechecked before body,
-	//	because body can contain a closure that captures the vars.
-	// 2. decldepth++ to denote loop body.
-	// 3. typecheck body.
-	// 4. decldepth--.
-	typecheckrangeExpr(n)
-
-	// second half of dance, the first half being typecheckrangeExpr
-	n.SetTypecheck(1)
-	ls := n.Vars
-	for i1, n1 := range ls {
-		if n1.Typecheck() == 0 {
-			ls[i1] = typecheck(ls[i1], ctxExpr|ctxAssign)
-		}
-	}
-
-	decldepth++
-	typecheckslice(n.Body, ctxStmt)
-	decldepth--
-}
-
-func typecheckrangeExpr(n *ir.RangeStmt) {
-	n.X = typecheck(n.X, ctxExpr)
-
-	t := n.X.Type()
-	if t == nil {
-		return
-	}
-	// delicate little dance.  see typecheckas2
-	ls := n.Vars
-	for i1, n1 := range ls {
-		if !ir.DeclaredBy(n1, n) {
-			ls[i1] = typecheck(ls[i1], ctxExpr|ctxAssign)
-		}
-	}
-
-	if t.IsPtr() && t.Elem().IsArray() {
-		t = t.Elem()
-	}
-	n.SetType(t)
-
-	var t1, t2 *types.Type
-	toomany := false
-	switch t.Kind() {
-	default:
-		base.ErrorfAt(n.Pos(), "cannot range over %L", n.X)
-		return
-
-	case types.TARRAY, types.TSLICE:
-		t1 = types.Types[types.TINT]
-		t2 = t.Elem()
-
-	case types.TMAP:
-		t1 = t.Key()
-		t2 = t.Elem()
-
-	case types.TCHAN:
-		if !t.ChanDir().CanRecv() {
-			base.ErrorfAt(n.Pos(), "invalid operation: range %v (receive from send-only type %v)", n.X, n.X.Type())
-			return
-		}
-
-		t1 = t.Elem()
-		t2 = nil
-		if len(n.Vars) == 2 {
-			toomany = true
-		}
-
-	case types.TSTRING:
-		t1 = types.Types[types.TINT]
-		t2 = types.RuneType
-	}
-
-	if len(n.Vars) > 2 || toomany {
-		base.ErrorfAt(n.Pos(), "too many variables in range")
-	}
-
-	var v1, v2 ir.Node
-	if len(n.Vars) != 0 {
-		v1 = n.Vars[0]
-	}
-	if len(n.Vars) > 1 {
-		v2 = n.Vars[1]
-	}
-
-	// this is not only an optimization but also a requirement in the spec.
-	// "if the second iteration variable is the blank identifier, the range
-	// clause is equivalent to the same clause with only the first variable
-	// present."
-	if ir.IsBlank(v2) {
-		if v1 != nil {
-			n.Vars = []ir.Node{v1}
-		}
-		v2 = nil
-	}
-
-	if v1 != nil {
-		if ir.DeclaredBy(v1, n) {
-			v1.SetType(t1)
-		} else if v1.Type() != nil {
-			if op, why := assignop(t1, v1.Type()); op == ir.OXXX {
-				base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t1, v1, why)
-			}
-		}
-		checkassign(n, v1)
-	}
-
-	if v2 != nil {
-		if ir.DeclaredBy(v2, n) {
-			v2.SetType(t2)
-		} else if v2.Type() != nil {
-			if op, why := assignop(t2, v2.Type()); op == ir.OXXX {
-				base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t2, v2, why)
-			}
-		}
-		checkassign(n, v2)
-	}
-}
-
 func cheapComputableIndex(width int64) bool {
 	switch thearch.LinkArch.Family {
 	// MIPS does not have R+R addressing
@@ -221,8 +97,8 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 		// order.stmt arranged for a copy of the array/slice variable if needed.
 		ha := a
 
-		hv1 := temp(types.Types[types.TINT])
-		hn := temp(types.Types[types.TINT])
+		hv1 := typecheck.Temp(types.Types[types.TINT])
+		hn := typecheck.Temp(types.Types[types.TINT])
 
 		init = append(init, ir.NewAssignStmt(base.Pos, hv1, nil))
 		init = append(init, ir.NewAssignStmt(base.Pos, hn, ir.NewUnaryExpr(base.Pos, ir.OLEN, ha)))
@@ -271,10 +147,10 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 		ifGuard.Cond = ir.NewBinaryExpr(base.Pos, ir.OLT, hv1, hn)
 		nfor.SetOp(ir.OFORUNTIL)
 
-		hp := temp(types.NewPtr(nrange.Type().Elem()))
+		hp := typecheck.Temp(types.NewPtr(nrange.Type().Elem()))
 		tmp := ir.NewIndexExpr(base.Pos, ha, ir.NewInt(0))
 		tmp.SetBounded(true)
-		init = append(init, ir.NewAssignStmt(base.Pos, hp, nodAddr(tmp)))
+		init = append(init, ir.NewAssignStmt(base.Pos, hp, typecheck.NodAddr(tmp)))
 
 		// Use OAS2 to correctly handle assignments
 		// of the form "v1, a[v1] := range".
@@ -289,7 +165,7 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 		// advancing the pointer is safe and won't go past the
 		// end of the allocation.
 		as := ir.NewAssignStmt(base.Pos, hp, addptr(hp, t.Elem().Width))
-		nfor.Late = []ir.Node{typecheck(as, ctxStmt)}
+		nfor.Late = []ir.Node{typecheck.Stmt(as)}
 
 	case types.TMAP:
 		// order.stmt allocated the iterator for us.
@@ -301,15 +177,15 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 		keysym := th.Field(0).Sym  // depends on layout of iterator struct.  See reflect.go:hiter
 		elemsym := th.Field(1).Sym // ditto
 
-		fn := syslook("mapiterinit")
+		fn := typecheck.LookupRuntime("mapiterinit")
 
-		fn = substArgTypes(fn, t.Key(), t.Elem(), th)
-		init = append(init, mkcall1(fn, nil, nil, typename(t), ha, nodAddr(hit)))
-		nfor.Cond = ir.NewBinaryExpr(base.Pos, ir.ONE, ir.NewSelectorExpr(base.Pos, ir.ODOT, hit, keysym), nodnil())
+		fn = typecheck.SubstArgTypes(fn, t.Key(), t.Elem(), th)
+		init = append(init, mkcall1(fn, nil, nil, typename(t), ha, typecheck.NodAddr(hit)))
+		nfor.Cond = ir.NewBinaryExpr(base.Pos, ir.ONE, ir.NewSelectorExpr(base.Pos, ir.ODOT, hit, keysym), typecheck.NodNil())
 
-		fn = syslook("mapiternext")
-		fn = substArgTypes(fn, th)
-		nfor.Post = mkcall1(fn, nil, nil, nodAddr(hit))
+		fn = typecheck.LookupRuntime("mapiternext")
+		fn = typecheck.SubstArgTypes(fn, th)
+		nfor.Post = mkcall1(fn, nil, nil, typecheck.NodAddr(hit))
 
 		key := ir.NewStarExpr(base.Pos, ir.NewSelectorExpr(base.Pos, ir.ODOT, hit, keysym))
 		if v1 == nil {
@@ -328,12 +204,12 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 		// order.stmt arranged for a copy of the channel variable.
 		ha := a
 
-		hv1 := temp(t.Elem())
+		hv1 := typecheck.Temp(t.Elem())
 		hv1.SetTypecheck(1)
 		if t.Elem().HasPointers() {
 			init = append(init, ir.NewAssignStmt(base.Pos, hv1, nil))
 		}
-		hb := temp(types.Types[types.TBOOL])
+		hb := typecheck.Temp(types.Types[types.TBOOL])
 
 		nfor.Cond = ir.NewBinaryExpr(base.Pos, ir.ONE, hb, ir.NewBool(false))
 		a := ir.NewAssignListStmt(base.Pos, ir.OAS2RECV, nil, nil)
@@ -370,9 +246,9 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 		// order.stmt arranged for a copy of the string variable.
 		ha := a
 
-		hv1 := temp(types.Types[types.TINT])
-		hv1t := temp(types.Types[types.TINT])
-		hv2 := temp(types.RuneType)
+		hv1 := typecheck.Temp(types.Types[types.TINT])
+		hv1t := typecheck.Temp(types.Types[types.TINT])
+		hv2 := typecheck.Temp(types.RuneType)
 
 		// hv1 := 0
 		init = append(init, ir.NewAssignStmt(base.Pos, hv1, nil))
@@ -388,7 +264,7 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 		// hv2 := rune(ha[hv1])
 		nind := ir.NewIndexExpr(base.Pos, ha, hv1)
 		nind.SetBounded(true)
-		body = append(body, ir.NewAssignStmt(base.Pos, hv2, conv(nind, types.RuneType)))
+		body = append(body, ir.NewAssignStmt(base.Pos, hv2, typecheck.Conv(nind, types.RuneType)))
 
 		// if hv2 < utf8.RuneSelf
 		nif := ir.NewIfStmt(base.Pos, nil, nil, nil)
@@ -403,7 +279,7 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 
 		// hv2, hv1 = decoderune(ha, hv1)
 		eif.Lhs = []ir.Node{hv2, hv1}
-		fn := syslook("decoderune")
+		fn := typecheck.LookupRuntime("decoderune")
 		eif.Rhs = []ir.Node{mkcall1(fn, fn.Type().Results(), nil, ha, hv1)}
 
 		body = append(body, nif)
@@ -422,21 +298,21 @@ func walkrange(nrange *ir.RangeStmt) ir.Node {
 		}
 	}
 
-	typecheckslice(init, ctxStmt)
+	typecheck.Stmts(init)
 
 	if ifGuard != nil {
 		ifGuard.PtrInit().Append(init...)
-		ifGuard = typecheck(ifGuard, ctxStmt).(*ir.IfStmt)
+		ifGuard = typecheck.Stmt(ifGuard).(*ir.IfStmt)
 	} else {
 		nfor.PtrInit().Append(init...)
 	}
 
-	typecheckslice(nfor.Cond.Init(), ctxStmt)
+	typecheck.Stmts(nfor.Cond.Init())
 
-	nfor.Cond = typecheck(nfor.Cond, ctxExpr)
-	nfor.Cond = defaultlit(nfor.Cond, nil)
-	nfor.Post = typecheck(nfor.Post, ctxStmt)
-	typecheckslice(body, ctxStmt)
+	nfor.Cond = typecheck.Expr(nfor.Cond)
+	nfor.Cond = typecheck.DefaultLit(nfor.Cond, nil)
+	nfor.Post = typecheck.Stmt(nfor.Post)
+	typecheck.Stmts(body)
 	nfor.Body.Append(body...)
 	nfor.Body.Append(nrange.Body...)
 
@@ -505,10 +381,10 @@ func mapClear(m ir.Node) ir.Node {
 	t := m.Type()
 
 	// instantiate mapclear(typ *type, hmap map[any]any)
-	fn := syslook("mapclear")
-	fn = substArgTypes(fn, t.Key(), t.Elem())
+	fn := typecheck.LookupRuntime("mapclear")
+	fn = typecheck.SubstArgTypes(fn, t.Key(), t.Elem())
 	n := mkcall1(fn, nil, nil, typename(t), m)
-	return walkstmt(typecheck(n, ctxStmt))
+	return walkstmt(typecheck.Stmt(n))
 }
 
 // Lower n into runtime·memclr if possible, for
@@ -566,16 +442,16 @@ func arrayClear(loop *ir.RangeStmt, v1, v2, a ir.Node) ir.Node {
 	n.Cond = ir.NewBinaryExpr(base.Pos, ir.ONE, ir.NewUnaryExpr(base.Pos, ir.OLEN, a), ir.NewInt(0))
 
 	// hp = &a[0]
-	hp := temp(types.Types[types.TUNSAFEPTR])
+	hp := typecheck.Temp(types.Types[types.TUNSAFEPTR])
 
 	ix := ir.NewIndexExpr(base.Pos, a, ir.NewInt(0))
 	ix.SetBounded(true)
-	addr := convnop(nodAddr(ix), types.Types[types.TUNSAFEPTR])
+	addr := typecheck.ConvNop(typecheck.NodAddr(ix), types.Types[types.TUNSAFEPTR])
 	n.Body.Append(ir.NewAssignStmt(base.Pos, hp, addr))
 
 	// hn = len(a) * sizeof(elem(a))
-	hn := temp(types.Types[types.TUINTPTR])
-	mul := conv(ir.NewBinaryExpr(base.Pos, ir.OMUL, ir.NewUnaryExpr(base.Pos, ir.OLEN, a), ir.NewInt(elemsize)), types.Types[types.TUINTPTR])
+	hn := typecheck.Temp(types.Types[types.TUINTPTR])
+	mul := typecheck.Conv(ir.NewBinaryExpr(base.Pos, ir.OMUL, ir.NewUnaryExpr(base.Pos, ir.OLEN, a), ir.NewInt(elemsize)), types.Types[types.TUINTPTR])
 	n.Body.Append(ir.NewAssignStmt(base.Pos, hn, mul))
 
 	var fn ir.Node
@@ -595,9 +471,9 @@ func arrayClear(loop *ir.RangeStmt, v1, v2, a ir.Node) ir.Node {
 
 	n.Body.Append(v1)
 
-	n.Cond = typecheck(n.Cond, ctxExpr)
-	n.Cond = defaultlit(n.Cond, nil)
-	typecheckslice(n.Body, ctxStmt)
+	n.Cond = typecheck.Expr(n.Cond)
+	n.Cond = typecheck.DefaultLit(n.Cond, nil)
+	typecheck.Stmts(n.Body)
 	return walkstmt(n)
 }
 
diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go
index 987b2d6ee2..7594884f9f 100644
--- a/src/cmd/compile/internal/gc/reflect.go
+++ b/src/cmd/compile/internal/gc/reflect.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/gcprog"
 	"cmd/internal/obj"
@@ -339,36 +340,6 @@ func deferstruct(stksize int64) *types.Type {
 	return s
 }
 
-// f is method type, with receiver.
-// return function type, receiver as first argument (or not).
-func methodfunc(f *types.Type, receiver *types.Type) *types.Type {
-	inLen := f.Params().Fields().Len()
-	if receiver != nil {
-		inLen++
-	}
-	in := make([]*ir.Field, 0, inLen)
-
-	if receiver != nil {
-		d := ir.NewField(base.Pos, nil, nil, receiver)
-		in = append(in, d)
-	}
-
-	for _, t := range f.Params().Fields().Slice() {
-		d := ir.NewField(base.Pos, nil, nil, t.Type)
-		d.IsDDD = t.IsDDD()
-		in = append(in, d)
-	}
-
-	outLen := f.Results().Fields().Len()
-	out := make([]*ir.Field, 0, outLen)
-	for _, t := range f.Results().Fields().Slice() {
-		d := ir.NewField(base.Pos, nil, nil, t.Type)
-		out = append(out, d)
-	}
-
-	return functype(nil, in, out)
-}
-
 // methods returns the methods of the non-interface type t, sorted by name.
 // Generates stub functions as needed.
 func methods(t *types.Type) []*Sig {
@@ -378,7 +349,7 @@ func methods(t *types.Type) []*Sig {
 	if mt == nil {
 		return nil
 	}
-	expandmeth(mt)
+	typecheck.CalcMethods(mt)
 
 	// type stored in interface word
 	it := t
@@ -418,8 +389,8 @@ func methods(t *types.Type) []*Sig {
 			name:  method,
 			isym:  ir.MethodSym(it, method),
 			tsym:  ir.MethodSym(t, method),
-			type_: methodfunc(f.Type, t),
-			mtype: methodfunc(f.Type, nil),
+			type_: typecheck.NewMethodType(f.Type, t),
+			mtype: typecheck.NewMethodType(f.Type, nil),
 		}
 		ms = append(ms, sig)
 
@@ -463,7 +434,7 @@ func imethods(t *types.Type) []*Sig {
 		sig := &Sig{
 			name:  f.Sym,
 			mtype: f.Type,
-			type_: methodfunc(f.Type, nil),
+			type_: typecheck.NewMethodType(f.Type, nil),
 		}
 		methods = append(methods, sig)
 
@@ -916,7 +887,7 @@ func typename(t *types.Type) *ir.AddrExpr {
 		s.Def = n
 	}
 
-	n := nodAddr(ir.AsNode(s.Def))
+	n := typecheck.NodAddr(ir.AsNode(s.Def))
 	n.SetType(types.NewPtr(s.Def.Type()))
 	n.SetTypecheck(1)
 	return n
@@ -928,7 +899,7 @@ func itabname(t, itype *types.Type) *ir.AddrExpr {
 	}
 	s := ir.Pkgs.Itab.Lookup(t.ShortString() + "," + itype.ShortString())
 	if s.Def == nil {
-		n := NewName(s)
+		n := typecheck.NewName(s)
 		n.SetType(types.Types[types.TUINT8])
 		n.Class_ = ir.PEXTERN
 		n.SetTypecheck(1)
@@ -936,7 +907,7 @@ func itabname(t, itype *types.Type) *ir.AddrExpr {
 		itabs = append(itabs, itabEntry{t: t, itype: itype, lsym: s.Linksym()})
 	}
 
-	n := nodAddr(ir.AsNode(s.Def))
+	n := typecheck.NodAddr(ir.AsNode(s.Def))
 	n.SetType(types.NewPtr(s.Def.Type()))
 	n.SetTypecheck(1)
 	return n
@@ -1033,7 +1004,7 @@ func dtypesym(t *types.Type) *obj.LSym {
 	if base.Ctxt.Pkgpath != "runtime" || (tbase != types.Types[tbase.Kind()] && tbase != types.ByteType && tbase != types.RuneType && tbase != types.ErrorType) { // int, float, etc
 		// named types from other files are defined only by those files
 		if tbase.Sym() != nil && tbase.Sym().Pkg != types.LocalPkg {
-			if i := BaseTypeIndex(t); i >= 0 {
+			if i := typecheck.BaseTypeIndex(t); i >= 0 {
 				lsym.Pkg = tbase.Sym().Pkg.Prefix
 				lsym.SymIdx = int32(i)
 				lsym.Set(obj.AttrIndexed, true)
@@ -1492,7 +1463,7 @@ func dumpbasictypes() {
 		// The latter is the type of an auto-generated wrapper.
 		dtypesym(types.NewPtr(types.ErrorType))
 
-		dtypesym(functype(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, types.ErrorType)}, []*ir.Field{ir.NewField(base.Pos, nil, nil, types.Types[types.TSTRING])}))
+		dtypesym(typecheck.NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, types.ErrorType)}, []*ir.Field{ir.NewField(base.Pos, nil, nil, types.Types[types.TSTRING])}))
 
 		// add paths for runtime and main, which 6l imports implicitly.
 		dimportpath(ir.Pkgs.Runtime)
@@ -1744,13 +1715,13 @@ func zeroaddr(size int64) ir.Node {
 	}
 	s := ir.Pkgs.Map.Lookup("zero")
 	if s.Def == nil {
-		x := NewName(s)
+		x := typecheck.NewName(s)
 		x.SetType(types.Types[types.TUINT8])
 		x.Class_ = ir.PEXTERN
 		x.SetTypecheck(1)
 		s.Def = x
 	}
-	z := nodAddr(ir.AsNode(s.Def))
+	z := typecheck.NodAddr(ir.AsNode(s.Def))
 	z.SetType(types.NewPtr(types.Types[types.TUINT8]))
 	z.SetTypecheck(1)
 	return z
diff --git a/src/cmd/compile/internal/gc/select.go b/src/cmd/compile/internal/gc/select.go
index 67a2cfd312..51bb1e5355 100644
--- a/src/cmd/compile/internal/gc/select.go
+++ b/src/cmd/compile/internal/gc/select.go
@@ -7,92 +7,10 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 )
 
-// select
-func typecheckselect(sel *ir.SelectStmt) {
-	var def ir.Node
-	lno := ir.SetPos(sel)
-	typecheckslice(sel.Init(), ctxStmt)
-	for _, ncase := range sel.Cases {
-		ncase := ncase.(*ir.CaseStmt)
-
-		if len(ncase.List) == 0 {
-			// default
-			if def != nil {
-				base.ErrorfAt(ncase.Pos(), "multiple defaults in select (first at %v)", ir.Line(def))
-			} else {
-				def = ncase
-			}
-		} else if len(ncase.List) > 1 {
-			base.ErrorfAt(ncase.Pos(), "select cases cannot be lists")
-		} else {
-			ncase.List[0] = typecheck(ncase.List[0], ctxStmt)
-			n := ncase.List[0]
-			ncase.Comm = n
-			ncase.List.Set(nil)
-			oselrecv2 := func(dst, recv ir.Node, colas bool) {
-				n := ir.NewAssignListStmt(n.Pos(), ir.OSELRECV2, nil, nil)
-				n.Lhs = []ir.Node{dst, ir.BlankNode}
-				n.Rhs = []ir.Node{recv}
-				n.Def = colas
-				n.SetTypecheck(1)
-				ncase.Comm = n
-			}
-			switch n.Op() {
-			default:
-				pos := n.Pos()
-				if n.Op() == ir.ONAME {
-					// We don't have the right position for ONAME nodes (see #15459 and
-					// others). Using ncase.Pos for now as it will provide the correct
-					// line number (assuming the expression follows the "case" keyword
-					// on the same line). This matches the approach before 1.10.
-					pos = ncase.Pos()
-				}
-				base.ErrorfAt(pos, "select case must be receive, send or assign recv")
-
-			case ir.OAS:
-				// convert x = <-c into x, _ = <-c
-				// remove implicit conversions; the eventual assignment
-				// will reintroduce them.
-				n := n.(*ir.AssignStmt)
-				if r := n.Y; r.Op() == ir.OCONVNOP || r.Op() == ir.OCONVIFACE {
-					r := r.(*ir.ConvExpr)
-					if r.Implicit() {
-						n.Y = r.X
-					}
-				}
-				if n.Y.Op() != ir.ORECV {
-					base.ErrorfAt(n.Pos(), "select assignment must have receive on right hand side")
-					break
-				}
-				oselrecv2(n.X, n.Y, n.Def)
-
-			case ir.OAS2RECV:
-				n := n.(*ir.AssignListStmt)
-				if n.Rhs[0].Op() != ir.ORECV {
-					base.ErrorfAt(n.Pos(), "select assignment must have receive on right hand side")
-					break
-				}
-				n.SetOp(ir.OSELRECV2)
-
-			case ir.ORECV:
-				// convert <-c into _, _ = <-c
-				n := n.(*ir.UnaryExpr)
-				oselrecv2(ir.BlankNode, n, false)
-
-			case ir.OSEND:
-				break
-			}
-		}
-
-		typecheckslice(ncase.Body, ctxStmt)
-	}
-
-	base.Pos = lno
-}
-
 func walkselect(sel *ir.SelectStmt) {
 	lno := ir.SetPos(sel)
 	if len(sel.Compiled) != 0 {
@@ -167,14 +85,14 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 		switch n.Op() {
 		case ir.OSEND:
 			n := n.(*ir.SendStmt)
-			n.Value = nodAddr(n.Value)
-			n.Value = typecheck(n.Value, ctxExpr)
+			n.Value = typecheck.NodAddr(n.Value)
+			n.Value = typecheck.Expr(n.Value)
 
 		case ir.OSELRECV2:
 			n := n.(*ir.AssignListStmt)
 			if !ir.IsBlank(n.Lhs[0]) {
-				n.Lhs[0] = nodAddr(n.Lhs[0])
-				n.Lhs[0] = typecheck(n.Lhs[0], ctxExpr)
+				n.Lhs[0] = typecheck.NodAddr(n.Lhs[0])
+				n.Lhs[0] = typecheck.Expr(n.Lhs[0])
 			}
 		}
 	}
@@ -207,7 +125,7 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 			ch := recv.X
 			elem := n.Lhs[0]
 			if ir.IsBlank(elem) {
-				elem = nodnil()
+				elem = typecheck.NodNil()
 			}
 			if ir.IsBlank(n.Lhs[1]) {
 				// if selectnbrecv(&v, c) { body } else { default body }
@@ -215,12 +133,12 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 			} else {
 				// TODO(cuonglm): make this use selectnbrecv()
 				// if selectnbrecv2(&v, &received, c) { body } else { default body }
-				receivedp := typecheck(nodAddr(n.Lhs[1]), ctxExpr)
+				receivedp := typecheck.Expr(typecheck.NodAddr(n.Lhs[1]))
 				call = mkcall1(chanfn("selectnbrecv2", 2, ch.Type()), types.Types[types.TBOOL], r.PtrInit(), elem, receivedp, ch)
 			}
 		}
 
-		r.Cond = typecheck(call, ctxExpr)
+		r.Cond = typecheck.Expr(call)
 		r.Body.Set(cas.Body)
 		r.Else.Set(append(dflt.Init(), dflt.Body...))
 		return []ir.Node{r, ir.NewBranchStmt(base.Pos, ir.OBREAK, nil)}
@@ -236,18 +154,18 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 
 	// generate sel-struct
 	base.Pos = sellineno
-	selv := temp(types.NewArray(scasetype(), int64(ncas)))
-	init = append(init, typecheck(ir.NewAssignStmt(base.Pos, selv, nil), ctxStmt))
+	selv := typecheck.Temp(types.NewArray(scasetype(), int64(ncas)))
+	init = append(init, typecheck.Stmt(ir.NewAssignStmt(base.Pos, selv, nil)))
 
 	// No initialization for order; runtime.selectgo is responsible for that.
-	order := temp(types.NewArray(types.Types[types.TUINT16], 2*int64(ncas)))
+	order := typecheck.Temp(types.NewArray(types.Types[types.TUINT16], 2*int64(ncas)))
 
 	var pc0, pcs ir.Node
 	if base.Flag.Race {
-		pcs = temp(types.NewArray(types.Types[types.TUINTPTR], int64(ncas)))
-		pc0 = typecheck(nodAddr(ir.NewIndexExpr(base.Pos, pcs, ir.NewInt(0))), ctxExpr)
+		pcs = typecheck.Temp(types.NewArray(types.Types[types.TUINTPTR], int64(ncas)))
+		pc0 = typecheck.Expr(typecheck.NodAddr(ir.NewIndexExpr(base.Pos, pcs, ir.NewInt(0))))
 	} else {
-		pc0 = nodnil()
+		pc0 = typecheck.NodNil()
 	}
 
 	// register cases
@@ -286,21 +204,21 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 		casorder[i] = cas
 
 		setField := func(f string, val ir.Node) {
-			r := ir.NewAssignStmt(base.Pos, ir.NewSelectorExpr(base.Pos, ir.ODOT, ir.NewIndexExpr(base.Pos, selv, ir.NewInt(int64(i))), lookup(f)), val)
-			init = append(init, typecheck(r, ctxStmt))
+			r := ir.NewAssignStmt(base.Pos, ir.NewSelectorExpr(base.Pos, ir.ODOT, ir.NewIndexExpr(base.Pos, selv, ir.NewInt(int64(i))), typecheck.Lookup(f)), val)
+			init = append(init, typecheck.Stmt(r))
 		}
 
-		c = convnop(c, types.Types[types.TUNSAFEPTR])
+		c = typecheck.ConvNop(c, types.Types[types.TUNSAFEPTR])
 		setField("c", c)
 		if !ir.IsBlank(elem) {
-			elem = convnop(elem, types.Types[types.TUNSAFEPTR])
+			elem = typecheck.ConvNop(elem, types.Types[types.TUNSAFEPTR])
 			setField("elem", elem)
 		}
 
 		// TODO(mdempsky): There should be a cleaner way to
 		// handle this.
 		if base.Flag.Race {
-			r := mkcall("selectsetpc", nil, nil, nodAddr(ir.NewIndexExpr(base.Pos, pcs, ir.NewInt(int64(i)))))
+			r := mkcall("selectsetpc", nil, nil, typecheck.NodAddr(ir.NewIndexExpr(base.Pos, pcs, ir.NewInt(int64(i)))))
 			init = append(init, r)
 		}
 	}
@@ -310,13 +228,13 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 
 	// run the select
 	base.Pos = sellineno
-	chosen := temp(types.Types[types.TINT])
-	recvOK := temp(types.Types[types.TBOOL])
+	chosen := typecheck.Temp(types.Types[types.TINT])
+	recvOK := typecheck.Temp(types.Types[types.TBOOL])
 	r := ir.NewAssignListStmt(base.Pos, ir.OAS2, nil, nil)
 	r.Lhs = []ir.Node{chosen, recvOK}
-	fn := syslook("selectgo")
+	fn := typecheck.LookupRuntime("selectgo")
 	r.Rhs = []ir.Node{mkcall1(fn, fn.Type().Results(), nil, bytePtrToIndex(selv, 0), bytePtrToIndex(order, 0), pc0, ir.NewInt(int64(nsends)), ir.NewInt(int64(nrecvs)), ir.NewBool(dflt == nil))}
-	init = append(init, typecheck(r, ctxStmt))
+	init = append(init, typecheck.Stmt(r))
 
 	// selv and order are no longer alive after selectgo.
 	init = append(init, ir.NewUnaryExpr(base.Pos, ir.OVARKILL, selv))
@@ -327,8 +245,8 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 
 	// dispatch cases
 	dispatch := func(cond ir.Node, cas *ir.CaseStmt) {
-		cond = typecheck(cond, ctxExpr)
-		cond = defaultlit(cond, nil)
+		cond = typecheck.Expr(cond)
+		cond = typecheck.DefaultLit(cond, nil)
 
 		r := ir.NewIfStmt(base.Pos, cond, nil, nil)
 
@@ -336,7 +254,7 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 			n := n.(*ir.AssignListStmt)
 			if !ir.IsBlank(n.Lhs[1]) {
 				x := ir.NewAssignStmt(base.Pos, n.Lhs[1], recvOK)
-				r.Body.Append(typecheck(x, ctxStmt))
+				r.Body.Append(typecheck.Stmt(x))
 			}
 		}
 
@@ -359,9 +277,9 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
 
 // bytePtrToIndex returns a Node representing "(*byte)(&n[i])".
 func bytePtrToIndex(n ir.Node, i int64) ir.Node {
-	s := nodAddr(ir.NewIndexExpr(base.Pos, n, ir.NewInt(i)))
+	s := typecheck.NodAddr(ir.NewIndexExpr(base.Pos, n, ir.NewInt(i)))
 	t := types.NewPtr(types.Types[types.TUINT8])
-	return convnop(s, t)
+	return typecheck.ConvNop(s, t)
 }
 
 var scase *types.Type
@@ -369,9 +287,9 @@ var scase *types.Type
 // Keep in sync with src/runtime/select.go.
 func scasetype() *types.Type {
 	if scase == nil {
-		scase = tostruct([]*ir.Field{
-			ir.NewField(base.Pos, lookup("c"), nil, types.Types[types.TUNSAFEPTR]),
-			ir.NewField(base.Pos, lookup("elem"), nil, types.Types[types.TUNSAFEPTR]),
+		scase = typecheck.NewStructType([]*ir.Field{
+			ir.NewField(base.Pos, typecheck.Lookup("c"), nil, types.Types[types.TUNSAFEPTR]),
+			ir.NewField(base.Pos, typecheck.Lookup("elem"), nil, types.Types[types.TUNSAFEPTR]),
 		})
 		scase.SetNoalg(true)
 	}
diff --git a/src/cmd/compile/internal/gc/sinit.go b/src/cmd/compile/internal/gc/sinit.go
index e9a4590043..26591ad5ab 100644
--- a/src/cmd/compile/internal/gc/sinit.go
+++ b/src/cmd/compile/internal/gc/sinit.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"fmt"
@@ -112,7 +113,7 @@ func (s *InitSchedule) staticcopy(l *ir.Name, loff int64, rn *ir.Name, typ *type
 		if loff != 0 || !types.Identical(typ, l.Type()) {
 			dst = ir.NewNameOffsetExpr(base.Pos, l, loff, typ)
 		}
-		s.append(ir.NewAssignStmt(base.Pos, dst, conv(r, typ)))
+		s.append(ir.NewAssignStmt(base.Pos, dst, typecheck.Conv(r, typ)))
 		return true
 
 	case ir.ONIL:
@@ -387,9 +388,9 @@ var statuniqgen int // name generator for static temps
 // Use readonlystaticname for read-only node.
 func staticname(t *types.Type) *ir.Name {
 	// Don't use lookupN; it interns the resulting string, but these are all unique.
-	n := NewName(lookup(fmt.Sprintf("%s%d", obj.StaticNamePref, statuniqgen)))
+	n := typecheck.NewName(typecheck.Lookup(fmt.Sprintf("%s%d", obj.StaticNamePref, statuniqgen)))
 	statuniqgen++
-	declare(n, ir.PEXTERN)
+	typecheck.Declare(n, ir.PEXTERN)
 	n.SetType(t)
 	n.Sym().Linksym().Set(obj.AttrLocal, true)
 	return n
@@ -541,7 +542,7 @@ func fixedlit(ctxt initContext, kind initKind, n *ir.CompLitExpr, var_ ir.Node,
 		splitnode = func(r ir.Node) (ir.Node, ir.Node) {
 			if r.Op() == ir.OKEY {
 				kv := r.(*ir.KeyExpr)
-				k = indexconst(kv.Key)
+				k = typecheck.IndexConst(kv.Key)
 				if k < 0 {
 					base.Fatalf("fixedlit: invalid index %v", kv.Key)
 				}
@@ -596,7 +597,7 @@ func fixedlit(ctxt initContext, kind initKind, n *ir.CompLitExpr, var_ ir.Node,
 		// build list of assignments: var[index] = expr
 		ir.SetPos(a)
 		as := ir.NewAssignStmt(base.Pos, a, value)
-		as = typecheck(as, ctxStmt).(*ir.AssignStmt)
+		as = typecheck.Stmt(as).(*ir.AssignStmt)
 		switch kind {
 		case initKindStatic:
 			genAsStatic(as)
@@ -632,7 +633,7 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 		fixedlit(ctxt, initKindDynamic, n, vstat, init)
 
 		// copy static to slice
-		var_ = typecheck(var_, ctxExpr|ctxAssign)
+		var_ = typecheck.AssignExpr(var_)
 		name, offset, ok := stataddr(var_)
 		if !ok || name.Class_ != ir.PEXTERN {
 			base.Fatalf("slicelit: %v", var_)
@@ -675,7 +676,7 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 	}
 
 	// make new auto *array (3 declare)
-	vauto := temp(types.NewPtr(t))
+	vauto := typecheck.Temp(types.NewPtr(t))
 
 	// set auto to point at new temp or heap (3 assign)
 	var a ir.Node
@@ -687,7 +688,7 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 
 		if vstat == nil {
 			a = ir.NewAssignStmt(base.Pos, x, nil)
-			a = typecheck(a, ctxStmt)
+			a = typecheck.Stmt(a)
 			init.Append(a) // zero new temp
 		} else {
 			// Declare that we're about to initialize all of x.
@@ -695,19 +696,19 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 			init.Append(ir.NewUnaryExpr(base.Pos, ir.OVARDEF, x))
 		}
 
-		a = nodAddr(x)
+		a = typecheck.NodAddr(x)
 	} else if n.Esc() == ir.EscNone {
-		a = temp(t)
+		a = typecheck.Temp(t)
 		if vstat == nil {
-			a = ir.NewAssignStmt(base.Pos, temp(t), nil)
-			a = typecheck(a, ctxStmt)
+			a = ir.NewAssignStmt(base.Pos, typecheck.Temp(t), nil)
+			a = typecheck.Stmt(a)
 			init.Append(a) // zero new temp
 			a = a.(*ir.AssignStmt).X
 		} else {
 			init.Append(ir.NewUnaryExpr(base.Pos, ir.OVARDEF, a))
 		}
 
-		a = nodAddr(a)
+		a = typecheck.NodAddr(a)
 	} else {
 		a = ir.NewUnaryExpr(base.Pos, ir.ONEW, ir.TypeNode(t))
 	}
@@ -724,7 +725,7 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 	for _, value := range n.List {
 		if value.Op() == ir.OKEY {
 			kv := value.(*ir.KeyExpr)
-			index = indexconst(kv.Key)
+			index = typecheck.IndexConst(kv.Key)
 			if index < 0 {
 				base.Fatalf("slicelit: invalid index %v", kv.Key)
 			}
@@ -758,7 +759,7 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 
 		// build list of vauto[c] = expr
 		ir.SetPos(value)
-		as := typecheck(ir.NewAssignStmt(base.Pos, a, value), ctxStmt)
+		as := typecheck.Stmt(ir.NewAssignStmt(base.Pos, a, value))
 		as = orderStmtInPlace(as, map[string][]*ir.Name{})
 		as = walkstmt(as)
 		init.Append(as)
@@ -767,7 +768,7 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)
 	// make slice out of heap (6)
 	a = ir.NewAssignStmt(base.Pos, var_, ir.NewSliceExpr(base.Pos, ir.OSLICE, vauto))
 
-	a = typecheck(a, ctxStmt)
+	a = typecheck.Stmt(a)
 	a = orderStmtInPlace(a, map[string][]*ir.Name{})
 	a = walkstmt(a)
 	init.Append(a)
@@ -822,7 +823,7 @@ func maplit(n *ir.CompLitExpr, m ir.Node, init *ir.Nodes) {
 		// for i = 0; i < len(vstatk); i++ {
 		//	map[vstatk[i]] = vstate[i]
 		// }
-		i := temp(types.Types[types.TINT])
+		i := typecheck.Temp(types.Types[types.TINT])
 		rhs := ir.NewIndexExpr(base.Pos, vstate, i)
 		rhs.SetBounded(true)
 
@@ -847,8 +848,8 @@ func maplit(n *ir.CompLitExpr, m ir.Node, init *ir.Nodes) {
 	// Build list of var[c] = expr.
 	// Use temporaries so that mapassign1 can have addressable key, elem.
 	// TODO(josharian): avoid map key temporaries for mapfast_* assignments with literal keys.
-	tmpkey := temp(m.Type().Key())
-	tmpelem := temp(m.Type().Elem())
+	tmpkey := typecheck.Temp(m.Type().Key())
+	tmpelem := typecheck.Temp(m.Type().Elem())
 
 	for _, r := range entries {
 		r := r.(*ir.KeyExpr)
@@ -892,7 +893,7 @@ func anylit(n ir.Node, var_ ir.Node, init *ir.Nodes) {
 		if n.Alloc != nil {
 			// n.Right is stack temporary used as backing store.
 			appendWalkStmt(init, ir.NewAssignStmt(base.Pos, n.Alloc, nil)) // zero backing store, just in case (#18410)
-			r = nodAddr(n.Alloc)
+			r = typecheck.NodAddr(n.Alloc)
 		} else {
 			r = ir.NewUnaryExpr(base.Pos, ir.ONEW, ir.TypeNode(n.X.Type()))
 			r.SetEsc(n.Esc())
@@ -900,7 +901,7 @@ func anylit(n ir.Node, var_ ir.Node, init *ir.Nodes) {
 		appendWalkStmt(init, ir.NewAssignStmt(base.Pos, var_, r))
 
 		var_ = ir.NewStarExpr(base.Pos, var_)
-		var_ = typecheck(var_, ctxExpr|ctxAssign)
+		var_ = typecheck.AssignExpr(var_)
 		anylit(n.X, var_, init)
 
 	case ir.OSTRUCTLIT, ir.OARRAYLIT:
@@ -1060,7 +1061,7 @@ func (s *InitSchedule) initplan(n ir.Node) {
 		for _, a := range n.List {
 			if a.Op() == ir.OKEY {
 				kv := a.(*ir.KeyExpr)
-				k = indexconst(kv.Key)
+				k = typecheck.IndexConst(kv.Key)
 				if k < 0 {
 					base.Fatalf("initplan arraylit: invalid index %v", kv.Key)
 				}
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 21925a0d65..382e4d4320 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -19,6 +19,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/ssa"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/obj/x86"
@@ -91,119 +92,119 @@ func initssaconfig() {
 	ssaCaches = make([]ssa.Cache, base.Flag.LowerC)
 
 	// Set up some runtime functions we'll need to call.
-	ir.Syms.AssertE2I = sysfunc("assertE2I")
-	ir.Syms.AssertE2I2 = sysfunc("assertE2I2")
-	ir.Syms.AssertI2I = sysfunc("assertI2I")
-	ir.Syms.AssertI2I2 = sysfunc("assertI2I2")
-	ir.Syms.Deferproc = sysfunc("deferproc")
-	ir.Syms.DeferprocStack = sysfunc("deferprocStack")
-	ir.Syms.Deferreturn = sysfunc("deferreturn")
-	ir.Syms.Duffcopy = sysfunc("duffcopy")
-	ir.Syms.Duffzero = sysfunc("duffzero")
-	ir.Syms.GCWriteBarrier = sysfunc("gcWriteBarrier")
-	ir.Syms.Goschedguarded = sysfunc("goschedguarded")
-	ir.Syms.Growslice = sysfunc("growslice")
-	ir.Syms.Msanread = sysfunc("msanread")
-	ir.Syms.Msanwrite = sysfunc("msanwrite")
-	ir.Syms.Msanmove = sysfunc("msanmove")
-	ir.Syms.Newobject = sysfunc("newobject")
-	ir.Syms.Newproc = sysfunc("newproc")
-	ir.Syms.Panicdivide = sysfunc("panicdivide")
-	ir.Syms.PanicdottypeE = sysfunc("panicdottypeE")
-	ir.Syms.PanicdottypeI = sysfunc("panicdottypeI")
-	ir.Syms.Panicnildottype = sysfunc("panicnildottype")
-	ir.Syms.Panicoverflow = sysfunc("panicoverflow")
-	ir.Syms.Panicshift = sysfunc("panicshift")
-	ir.Syms.Raceread = sysfunc("raceread")
-	ir.Syms.Racereadrange = sysfunc("racereadrange")
-	ir.Syms.Racewrite = sysfunc("racewrite")
-	ir.Syms.Racewriterange = sysfunc("racewriterange")
-	ir.Syms.X86HasPOPCNT = sysvar("x86HasPOPCNT")       // bool
-	ir.Syms.X86HasSSE41 = sysvar("x86HasSSE41")         // bool
-	ir.Syms.X86HasFMA = sysvar("x86HasFMA")             // bool
-	ir.Syms.ARMHasVFPv4 = sysvar("armHasVFPv4")         // bool
-	ir.Syms.ARM64HasATOMICS = sysvar("arm64HasATOMICS") // bool
-	ir.Syms.Typedmemclr = sysfunc("typedmemclr")
-	ir.Syms.Typedmemmove = sysfunc("typedmemmove")
-	ir.Syms.Udiv = sysvar("udiv")                 // asm func with special ABI
-	ir.Syms.WriteBarrier = sysvar("writeBarrier") // struct { bool; ... }
-	ir.Syms.Zerobase = sysvar("zerobase")
+	ir.Syms.AssertE2I = typecheck.LookupRuntimeFunc("assertE2I")
+	ir.Syms.AssertE2I2 = typecheck.LookupRuntimeFunc("assertE2I2")
+	ir.Syms.AssertI2I = typecheck.LookupRuntimeFunc("assertI2I")
+	ir.Syms.AssertI2I2 = typecheck.LookupRuntimeFunc("assertI2I2")
+	ir.Syms.Deferproc = typecheck.LookupRuntimeFunc("deferproc")
+	ir.Syms.DeferprocStack = typecheck.LookupRuntimeFunc("deferprocStack")
+	ir.Syms.Deferreturn = typecheck.LookupRuntimeFunc("deferreturn")
+	ir.Syms.Duffcopy = typecheck.LookupRuntimeFunc("duffcopy")
+	ir.Syms.Duffzero = typecheck.LookupRuntimeFunc("duffzero")
+	ir.Syms.GCWriteBarrier = typecheck.LookupRuntimeFunc("gcWriteBarrier")
+	ir.Syms.Goschedguarded = typecheck.LookupRuntimeFunc("goschedguarded")
+	ir.Syms.Growslice = typecheck.LookupRuntimeFunc("growslice")
+	ir.Syms.Msanread = typecheck.LookupRuntimeFunc("msanread")
+	ir.Syms.Msanwrite = typecheck.LookupRuntimeFunc("msanwrite")
+	ir.Syms.Msanmove = typecheck.LookupRuntimeFunc("msanmove")
+	ir.Syms.Newobject = typecheck.LookupRuntimeFunc("newobject")
+	ir.Syms.Newproc = typecheck.LookupRuntimeFunc("newproc")
+	ir.Syms.Panicdivide = typecheck.LookupRuntimeFunc("panicdivide")
+	ir.Syms.PanicdottypeE = typecheck.LookupRuntimeFunc("panicdottypeE")
+	ir.Syms.PanicdottypeI = typecheck.LookupRuntimeFunc("panicdottypeI")
+	ir.Syms.Panicnildottype = typecheck.LookupRuntimeFunc("panicnildottype")
+	ir.Syms.Panicoverflow = typecheck.LookupRuntimeFunc("panicoverflow")
+	ir.Syms.Panicshift = typecheck.LookupRuntimeFunc("panicshift")
+	ir.Syms.Raceread = typecheck.LookupRuntimeFunc("raceread")
+	ir.Syms.Racereadrange = typecheck.LookupRuntimeFunc("racereadrange")
+	ir.Syms.Racewrite = typecheck.LookupRuntimeFunc("racewrite")
+	ir.Syms.Racewriterange = typecheck.LookupRuntimeFunc("racewriterange")
+	ir.Syms.X86HasPOPCNT = typecheck.LookupRuntimeVar("x86HasPOPCNT")       // bool
+	ir.Syms.X86HasSSE41 = typecheck.LookupRuntimeVar("x86HasSSE41")         // bool
+	ir.Syms.X86HasFMA = typecheck.LookupRuntimeVar("x86HasFMA")             // bool
+	ir.Syms.ARMHasVFPv4 = typecheck.LookupRuntimeVar("armHasVFPv4")         // bool
+	ir.Syms.ARM64HasATOMICS = typecheck.LookupRuntimeVar("arm64HasATOMICS") // bool
+	ir.Syms.Typedmemclr = typecheck.LookupRuntimeFunc("typedmemclr")
+	ir.Syms.Typedmemmove = typecheck.LookupRuntimeFunc("typedmemmove")
+	ir.Syms.Udiv = typecheck.LookupRuntimeVar("udiv")                 // asm func with special ABI
+	ir.Syms.WriteBarrier = typecheck.LookupRuntimeVar("writeBarrier") // struct { bool; ... }
+	ir.Syms.Zerobase = typecheck.LookupRuntimeVar("zerobase")
 
 	// asm funcs with special ABI
 	if thearch.LinkArch.Name == "amd64" {
 		GCWriteBarrierReg = map[int16]*obj.LSym{
-			x86.REG_AX: sysfunc("gcWriteBarrier"),
-			x86.REG_CX: sysfunc("gcWriteBarrierCX"),
-			x86.REG_DX: sysfunc("gcWriteBarrierDX"),
-			x86.REG_BX: sysfunc("gcWriteBarrierBX"),
-			x86.REG_BP: sysfunc("gcWriteBarrierBP"),
-			x86.REG_SI: sysfunc("gcWriteBarrierSI"),
-			x86.REG_R8: sysfunc("gcWriteBarrierR8"),
-			x86.REG_R9: sysfunc("gcWriteBarrierR9"),
+			x86.REG_AX: typecheck.LookupRuntimeFunc("gcWriteBarrier"),
+			x86.REG_CX: typecheck.LookupRuntimeFunc("gcWriteBarrierCX"),
+			x86.REG_DX: typecheck.LookupRuntimeFunc("gcWriteBarrierDX"),
+			x86.REG_BX: typecheck.LookupRuntimeFunc("gcWriteBarrierBX"),
+			x86.REG_BP: typecheck.LookupRuntimeFunc("gcWriteBarrierBP"),
+			x86.REG_SI: typecheck.LookupRuntimeFunc("gcWriteBarrierSI"),
+			x86.REG_R8: typecheck.LookupRuntimeFunc("gcWriteBarrierR8"),
+			x86.REG_R9: typecheck.LookupRuntimeFunc("gcWriteBarrierR9"),
 		}
 	}
 
 	if thearch.LinkArch.Family == sys.Wasm {
-		BoundsCheckFunc[ssa.BoundsIndex] = sysfunc("goPanicIndex")
-		BoundsCheckFunc[ssa.BoundsIndexU] = sysfunc("goPanicIndexU")
-		BoundsCheckFunc[ssa.BoundsSliceAlen] = sysfunc("goPanicSliceAlen")
-		BoundsCheckFunc[ssa.BoundsSliceAlenU] = sysfunc("goPanicSliceAlenU")
-		BoundsCheckFunc[ssa.BoundsSliceAcap] = sysfunc("goPanicSliceAcap")
-		BoundsCheckFunc[ssa.BoundsSliceAcapU] = sysfunc("goPanicSliceAcapU")
-		BoundsCheckFunc[ssa.BoundsSliceB] = sysfunc("goPanicSliceB")
-		BoundsCheckFunc[ssa.BoundsSliceBU] = sysfunc("goPanicSliceBU")
-		BoundsCheckFunc[ssa.BoundsSlice3Alen] = sysfunc("goPanicSlice3Alen")
-		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = sysfunc("goPanicSlice3AlenU")
-		BoundsCheckFunc[ssa.BoundsSlice3Acap] = sysfunc("goPanicSlice3Acap")
-		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = sysfunc("goPanicSlice3AcapU")
-		BoundsCheckFunc[ssa.BoundsSlice3B] = sysfunc("goPanicSlice3B")
-		BoundsCheckFunc[ssa.BoundsSlice3BU] = sysfunc("goPanicSlice3BU")
-		BoundsCheckFunc[ssa.BoundsSlice3C] = sysfunc("goPanicSlice3C")
-		BoundsCheckFunc[ssa.BoundsSlice3CU] = sysfunc("goPanicSlice3CU")
+		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("goPanicIndex")
+		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("goPanicIndexU")
+		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("goPanicSliceAlen")
+		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("goPanicSliceAlenU")
+		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("goPanicSliceAcap")
+		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("goPanicSliceAcapU")
+		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("goPanicSliceB")
+		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("goPanicSliceBU")
+		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("goPanicSlice3Alen")
+		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("goPanicSlice3AlenU")
+		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("goPanicSlice3Acap")
+		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("goPanicSlice3AcapU")
+		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("goPanicSlice3B")
+		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("goPanicSlice3BU")
+		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("goPanicSlice3C")
+		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("goPanicSlice3CU")
 	} else {
-		BoundsCheckFunc[ssa.BoundsIndex] = sysfunc("panicIndex")
-		BoundsCheckFunc[ssa.BoundsIndexU] = sysfunc("panicIndexU")
-		BoundsCheckFunc[ssa.BoundsSliceAlen] = sysfunc("panicSliceAlen")
-		BoundsCheckFunc[ssa.BoundsSliceAlenU] = sysfunc("panicSliceAlenU")
-		BoundsCheckFunc[ssa.BoundsSliceAcap] = sysfunc("panicSliceAcap")
-		BoundsCheckFunc[ssa.BoundsSliceAcapU] = sysfunc("panicSliceAcapU")
-		BoundsCheckFunc[ssa.BoundsSliceB] = sysfunc("panicSliceB")
-		BoundsCheckFunc[ssa.BoundsSliceBU] = sysfunc("panicSliceBU")
-		BoundsCheckFunc[ssa.BoundsSlice3Alen] = sysfunc("panicSlice3Alen")
-		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = sysfunc("panicSlice3AlenU")
-		BoundsCheckFunc[ssa.BoundsSlice3Acap] = sysfunc("panicSlice3Acap")
-		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = sysfunc("panicSlice3AcapU")
-		BoundsCheckFunc[ssa.BoundsSlice3B] = sysfunc("panicSlice3B")
-		BoundsCheckFunc[ssa.BoundsSlice3BU] = sysfunc("panicSlice3BU")
-		BoundsCheckFunc[ssa.BoundsSlice3C] = sysfunc("panicSlice3C")
-		BoundsCheckFunc[ssa.BoundsSlice3CU] = sysfunc("panicSlice3CU")
+		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("panicIndex")
+		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("panicIndexU")
+		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("panicSliceAlen")
+		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("panicSliceAlenU")
+		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("panicSliceAcap")
+		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("panicSliceAcapU")
+		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("panicSliceB")
+		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("panicSliceBU")
+		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("panicSlice3Alen")
+		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("panicSlice3AlenU")
+		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("panicSlice3Acap")
+		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("panicSlice3AcapU")
+		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("panicSlice3B")
+		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("panicSlice3BU")
+		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("panicSlice3C")
+		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("panicSlice3CU")
 	}
 	if thearch.LinkArch.PtrSize == 4 {
-		ExtendCheckFunc[ssa.BoundsIndex] = sysvar("panicExtendIndex")
-		ExtendCheckFunc[ssa.BoundsIndexU] = sysvar("panicExtendIndexU")
-		ExtendCheckFunc[ssa.BoundsSliceAlen] = sysvar("panicExtendSliceAlen")
-		ExtendCheckFunc[ssa.BoundsSliceAlenU] = sysvar("panicExtendSliceAlenU")
-		ExtendCheckFunc[ssa.BoundsSliceAcap] = sysvar("panicExtendSliceAcap")
-		ExtendCheckFunc[ssa.BoundsSliceAcapU] = sysvar("panicExtendSliceAcapU")
-		ExtendCheckFunc[ssa.BoundsSliceB] = sysvar("panicExtendSliceB")
-		ExtendCheckFunc[ssa.BoundsSliceBU] = sysvar("panicExtendSliceBU")
-		ExtendCheckFunc[ssa.BoundsSlice3Alen] = sysvar("panicExtendSlice3Alen")
-		ExtendCheckFunc[ssa.BoundsSlice3AlenU] = sysvar("panicExtendSlice3AlenU")
-		ExtendCheckFunc[ssa.BoundsSlice3Acap] = sysvar("panicExtendSlice3Acap")
-		ExtendCheckFunc[ssa.BoundsSlice3AcapU] = sysvar("panicExtendSlice3AcapU")
-		ExtendCheckFunc[ssa.BoundsSlice3B] = sysvar("panicExtendSlice3B")
-		ExtendCheckFunc[ssa.BoundsSlice3BU] = sysvar("panicExtendSlice3BU")
-		ExtendCheckFunc[ssa.BoundsSlice3C] = sysvar("panicExtendSlice3C")
-		ExtendCheckFunc[ssa.BoundsSlice3CU] = sysvar("panicExtendSlice3CU")
+		ExtendCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeVar("panicExtendIndex")
+		ExtendCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeVar("panicExtendIndexU")
+		ExtendCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeVar("panicExtendSliceAlen")
+		ExtendCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeVar("panicExtendSliceAlenU")
+		ExtendCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeVar("panicExtendSliceAcap")
+		ExtendCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeVar("panicExtendSliceAcapU")
+		ExtendCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeVar("panicExtendSliceB")
+		ExtendCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeVar("panicExtendSliceBU")
+		ExtendCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeVar("panicExtendSlice3Alen")
+		ExtendCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeVar("panicExtendSlice3AlenU")
+		ExtendCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeVar("panicExtendSlice3Acap")
+		ExtendCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeVar("panicExtendSlice3AcapU")
+		ExtendCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeVar("panicExtendSlice3B")
+		ExtendCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeVar("panicExtendSlice3BU")
+		ExtendCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeVar("panicExtendSlice3C")
+		ExtendCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeVar("panicExtendSlice3CU")
 	}
 
 	// Wasm (all asm funcs with special ABIs)
-	ir.Syms.WasmMove = sysvar("wasmMove")
-	ir.Syms.WasmZero = sysvar("wasmZero")
-	ir.Syms.WasmDiv = sysvar("wasmDiv")
-	ir.Syms.WasmTruncS = sysvar("wasmTruncS")
-	ir.Syms.WasmTruncU = sysvar("wasmTruncU")
-	ir.Syms.SigPanic = sysfunc("sigpanic")
+	ir.Syms.WasmMove = typecheck.LookupRuntimeVar("wasmMove")
+	ir.Syms.WasmZero = typecheck.LookupRuntimeVar("wasmZero")
+	ir.Syms.WasmDiv = typecheck.LookupRuntimeVar("wasmDiv")
+	ir.Syms.WasmTruncS = typecheck.LookupRuntimeVar("wasmTruncS")
+	ir.Syms.WasmTruncU = typecheck.LookupRuntimeVar("wasmTruncU")
+	ir.Syms.SigPanic = typecheck.LookupRuntimeFunc("sigpanic")
 }
 
 // getParam returns the Field of ith param of node n (which is a
@@ -418,7 +419,7 @@ func buildssa(fn *ir.Func, worker int) *ssa.Func {
 		// Create the deferBits variable and stack slot.  deferBits is a
 		// bitmask showing which of the open-coded defers in this function
 		// have been activated.
-		deferBitsTemp := tempAt(src.NoXPos, s.curfn, types.Types[types.TUINT8])
+		deferBitsTemp := typecheck.TempAt(src.NoXPos, s.curfn, types.Types[types.TUINT8])
 		s.deferBitsTemp = deferBitsTemp
 		// For this value, AuxInt is initialized to zero by default
 		startDeferBits := s.entryNewValue0(ssa.OpConst8, types.Types[types.TUINT8])
@@ -710,7 +711,7 @@ func (s *state) Warnl(pos src.XPos, msg string, args ...interface{}) { s.f.Warnl
 func (s *state) Debug_checknil() bool                                { return s.f.Frontend().Debug_checknil() }
 
 func ssaMarker(name string) *ir.Name {
-	return NewName(&types.Sym{Name: name})
+	return typecheck.NewName(&types.Sym{Name: name})
 }
 
 var (
@@ -3342,38 +3343,38 @@ var softFloatOps map[ssa.Op]sfRtCallDef
 func softfloatInit() {
 	// Some of these operations get transformed by sfcall.
 	softFloatOps = map[ssa.Op]sfRtCallDef{
-		ssa.OpAdd32F: sfRtCallDef{sysfunc("fadd32"), types.TFLOAT32},
-		ssa.OpAdd64F: sfRtCallDef{sysfunc("fadd64"), types.TFLOAT64},
-		ssa.OpSub32F: sfRtCallDef{sysfunc("fadd32"), types.TFLOAT32},
-		ssa.OpSub64F: sfRtCallDef{sysfunc("fadd64"), types.TFLOAT64},
-		ssa.OpMul32F: sfRtCallDef{sysfunc("fmul32"), types.TFLOAT32},
-		ssa.OpMul64F: sfRtCallDef{sysfunc("fmul64"), types.TFLOAT64},
-		ssa.OpDiv32F: sfRtCallDef{sysfunc("fdiv32"), types.TFLOAT32},
-		ssa.OpDiv64F: sfRtCallDef{sysfunc("fdiv64"), types.TFLOAT64},
+		ssa.OpAdd32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
+		ssa.OpAdd64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
+		ssa.OpSub32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
+		ssa.OpSub64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
+		ssa.OpMul32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fmul32"), types.TFLOAT32},
+		ssa.OpMul64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fmul64"), types.TFLOAT64},
+		ssa.OpDiv32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fdiv32"), types.TFLOAT32},
+		ssa.OpDiv64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fdiv64"), types.TFLOAT64},
 
-		ssa.OpEq64F:   sfRtCallDef{sysfunc("feq64"), types.TBOOL},
-		ssa.OpEq32F:   sfRtCallDef{sysfunc("feq32"), types.TBOOL},
-		ssa.OpNeq64F:  sfRtCallDef{sysfunc("feq64"), types.TBOOL},
-		ssa.OpNeq32F:  sfRtCallDef{sysfunc("feq32"), types.TBOOL},
-		ssa.OpLess64F: sfRtCallDef{sysfunc("fgt64"), types.TBOOL},
-		ssa.OpLess32F: sfRtCallDef{sysfunc("fgt32"), types.TBOOL},
-		ssa.OpLeq64F:  sfRtCallDef{sysfunc("fge64"), types.TBOOL},
-		ssa.OpLeq32F:  sfRtCallDef{sysfunc("fge32"), types.TBOOL},
+		ssa.OpEq64F:   sfRtCallDef{typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
+		ssa.OpEq32F:   sfRtCallDef{typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
+		ssa.OpNeq64F:  sfRtCallDef{typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
+		ssa.OpNeq32F:  sfRtCallDef{typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
+		ssa.OpLess64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fgt64"), types.TBOOL},
+		ssa.OpLess32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fgt32"), types.TBOOL},
+		ssa.OpLeq64F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fge64"), types.TBOOL},
+		ssa.OpLeq32F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fge32"), types.TBOOL},
 
-		ssa.OpCvt32to32F:  sfRtCallDef{sysfunc("fint32to32"), types.TFLOAT32},
-		ssa.OpCvt32Fto32:  sfRtCallDef{sysfunc("f32toint32"), types.TINT32},
-		ssa.OpCvt64to32F:  sfRtCallDef{sysfunc("fint64to32"), types.TFLOAT32},
-		ssa.OpCvt32Fto64:  sfRtCallDef{sysfunc("f32toint64"), types.TINT64},
-		ssa.OpCvt64Uto32F: sfRtCallDef{sysfunc("fuint64to32"), types.TFLOAT32},
-		ssa.OpCvt32Fto64U: sfRtCallDef{sysfunc("f32touint64"), types.TUINT64},
-		ssa.OpCvt32to64F:  sfRtCallDef{sysfunc("fint32to64"), types.TFLOAT64},
-		ssa.OpCvt64Fto32:  sfRtCallDef{sysfunc("f64toint32"), types.TINT32},
-		ssa.OpCvt64to64F:  sfRtCallDef{sysfunc("fint64to64"), types.TFLOAT64},
-		ssa.OpCvt64Fto64:  sfRtCallDef{sysfunc("f64toint64"), types.TINT64},
-		ssa.OpCvt64Uto64F: sfRtCallDef{sysfunc("fuint64to64"), types.TFLOAT64},
-		ssa.OpCvt64Fto64U: sfRtCallDef{sysfunc("f64touint64"), types.TUINT64},
-		ssa.OpCvt32Fto64F: sfRtCallDef{sysfunc("f32to64"), types.TFLOAT64},
-		ssa.OpCvt64Fto32F: sfRtCallDef{sysfunc("f64to32"), types.TFLOAT32},
+		ssa.OpCvt32to32F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fint32to32"), types.TFLOAT32},
+		ssa.OpCvt32Fto32:  sfRtCallDef{typecheck.LookupRuntimeFunc("f32toint32"), types.TINT32},
+		ssa.OpCvt64to32F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fint64to32"), types.TFLOAT32},
+		ssa.OpCvt32Fto64:  sfRtCallDef{typecheck.LookupRuntimeFunc("f32toint64"), types.TINT64},
+		ssa.OpCvt64Uto32F: sfRtCallDef{typecheck.LookupRuntimeFunc("fuint64to32"), types.TFLOAT32},
+		ssa.OpCvt32Fto64U: sfRtCallDef{typecheck.LookupRuntimeFunc("f32touint64"), types.TUINT64},
+		ssa.OpCvt32to64F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fint32to64"), types.TFLOAT64},
+		ssa.OpCvt64Fto32:  sfRtCallDef{typecheck.LookupRuntimeFunc("f64toint32"), types.TINT32},
+		ssa.OpCvt64to64F:  sfRtCallDef{typecheck.LookupRuntimeFunc("fint64to64"), types.TFLOAT64},
+		ssa.OpCvt64Fto64:  sfRtCallDef{typecheck.LookupRuntimeFunc("f64toint64"), types.TINT64},
+		ssa.OpCvt64Uto64F: sfRtCallDef{typecheck.LookupRuntimeFunc("fuint64to64"), types.TFLOAT64},
+		ssa.OpCvt64Fto64U: sfRtCallDef{typecheck.LookupRuntimeFunc("f64touint64"), types.TUINT64},
+		ssa.OpCvt32Fto64F: sfRtCallDef{typecheck.LookupRuntimeFunc("f32to64"), types.TFLOAT64},
+		ssa.OpCvt64Fto32F: sfRtCallDef{typecheck.LookupRuntimeFunc("f64to32"), types.TFLOAT32},
 	}
 }
 
@@ -4458,7 +4459,7 @@ func (s *state) openDeferSave(n ir.Node, t *types.Type, val *ssa.Value) *ssa.Val
 	} else {
 		pos = n.Pos()
 	}
-	argTemp := tempAt(pos.WithNotStmt(), s.curfn, t)
+	argTemp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
 	argTemp.SetOpenDeferSlot(true)
 	var addrArgTemp *ssa.Value
 	// Use OpVarLive to make sure stack slots for the args, etc. are not
@@ -4719,7 +4720,7 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
 		testLateExpansion = ssa.LateCallExpansionEnabledWithin(s.f)
 		// Make a defer struct d on the stack.
 		t := deferstruct(stksize)
-		d := tempAt(n.Pos(), s.curfn, t)
+		d := typecheck.TempAt(n.Pos(), s.curfn, t)
 
 		s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, d, s.mem())
 		addr := s.addr(d)
@@ -6144,7 +6145,7 @@ func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Val
 	if commaok && !canSSAType(n.Type()) {
 		// unSSAable type, use temporary.
 		// TODO: get rid of some of these temporaries.
-		tmp = tempAt(n.Pos(), s.curfn, n.Type())
+		tmp = typecheck.TempAt(n.Pos(), s.curfn, n.Type())
 		s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp.(*ir.Name), s.mem())
 		addr = s.addr(tmp)
 	}
@@ -7173,7 +7174,7 @@ func (e *ssafn) StringData(s string) *obj.LSym {
 }
 
 func (e *ssafn) Auto(pos src.XPos, t *types.Type) *ir.Name {
-	return tempAt(pos, e.curfn, t) // Note: adds new auto to e.curfn.Func.Dcl list
+	return typecheck.TempAt(pos, e.curfn, t) // Note: adds new auto to e.curfn.Func.Dcl list
 }
 
 func (e *ssafn) SplitString(name ssa.LocalSlot) (ssa.LocalSlot, ssa.LocalSlot) {
diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index d4c7c6db1a..8e2093d488 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -7,11 +7,10 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
 	"fmt"
-	"sort"
-	"strconv"
 	"strings"
 	"sync"
 	"unicode"
@@ -31,71 +30,35 @@ var (
 	largeStackFrames   []largeStack
 )
 
-func lookup(name string) *types.Sym {
-	return types.LocalPkg.Lookup(name)
-}
-
-// lookupN looks up the symbol starting with prefix and ending with
-// the decimal n. If prefix is too long, lookupN panics.
-func lookupN(prefix string, n int) *types.Sym {
-	var buf [20]byte // plenty long enough for all current users
-	copy(buf[:], prefix)
-	b := strconv.AppendInt(buf[:len(prefix)], int64(n), 10)
-	return types.LocalPkg.LookupBytes(b)
-}
-
-// autolabel generates a new Name node for use with
-// an automatically generated label.
-// prefix is a short mnemonic (e.g. ".s" for switch)
-// to help with debugging.
-// It should begin with "." to avoid conflicts with
-// user labels.
-func autolabel(prefix string) *types.Sym {
-	if prefix[0] != '.' {
-		base.Fatalf("autolabel prefix must start with '.', have %q", prefix)
-	}
-	fn := ir.CurFunc
-	if ir.CurFunc == nil {
-		base.Fatalf("autolabel outside function")
-	}
-	n := fn.Label
-	fn.Label++
-	return lookupN(prefix, int(n))
-}
-
 // dotImports tracks all PkgNames that have been dot-imported.
 var dotImports []*ir.PkgName
 
-// dotImportRefs maps idents introduced by importDot back to the
-// ir.PkgName they were dot-imported through.
-var dotImportRefs map[*ir.Ident]*ir.PkgName
-
 // find all the exported symbols in package referenced by PkgName,
 // and make them available in the current package
 func importDot(pack *ir.PkgName) {
-	if dotImportRefs == nil {
-		dotImportRefs = make(map[*ir.Ident]*ir.PkgName)
+	if typecheck.DotImportRefs == nil {
+		typecheck.DotImportRefs = make(map[*ir.Ident]*ir.PkgName)
 	}
 
 	opkg := pack.Pkg
 	for _, s := range opkg.Syms {
 		if s.Def == nil {
-			if _, ok := declImporter[s]; !ok {
+			if _, ok := typecheck.DeclImporter[s]; !ok {
 				continue
 			}
 		}
 		if !types.IsExported(s.Name) || strings.ContainsRune(s.Name, 0xb7) { // 0xb7 = center dot
 			continue
 		}
-		s1 := lookup(s.Name)
+		s1 := typecheck.Lookup(s.Name)
 		if s1.Def != nil {
 			pkgerror := fmt.Sprintf("during import %q", opkg.Path)
-			redeclare(base.Pos, s1, pkgerror)
+			typecheck.Redeclared(base.Pos, s1, pkgerror)
 			continue
 		}
 
 		id := ir.NewIdent(src.NoXPos, s)
-		dotImportRefs[id] = pack
+		typecheck.DotImportRefs[id] = pack
 		s1.Def = id
 		s1.Block = 1
 	}
@@ -113,347 +76,7 @@ func checkDotImports() {
 
 	// No longer needed; release memory.
 	dotImports = nil
-	dotImportRefs = nil
-}
-
-// nodAddr returns a node representing &n at base.Pos.
-func nodAddr(n ir.Node) *ir.AddrExpr {
-	return nodAddrAt(base.Pos, n)
-}
-
-// nodAddrPos returns a node representing &n at position pos.
-func nodAddrAt(pos src.XPos, n ir.Node) *ir.AddrExpr {
-	return ir.NewAddrExpr(pos, n)
-}
-
-// newname returns a new ONAME Node associated with symbol s.
-func NewName(s *types.Sym) *ir.Name {
-	n := ir.NewNameAt(base.Pos, s)
-	n.Curfn = ir.CurFunc
-	return n
-}
-
-func nodnil() ir.Node {
-	n := ir.NewNilExpr(base.Pos)
-	n.SetType(types.Types[types.TNIL])
-	return n
-}
-
-func isptrto(t *types.Type, et types.Kind) bool {
-	if t == nil {
-		return false
-	}
-	if !t.IsPtr() {
-		return false
-	}
-	t = t.Elem()
-	if t == nil {
-		return false
-	}
-	if t.Kind() != et {
-		return false
-	}
-	return true
-}
-
-// Is type src assignment compatible to type dst?
-// If so, return op code to use in conversion.
-// If not, return OXXX. In this case, the string return parameter may
-// hold a reason why. In all other cases, it'll be the empty string.
-func assignop(src, dst *types.Type) (ir.Op, string) {
-	if src == dst {
-		return ir.OCONVNOP, ""
-	}
-	if src == nil || dst == nil || src.Kind() == types.TFORW || dst.Kind() == types.TFORW || src.Underlying() == nil || dst.Underlying() == nil {
-		return ir.OXXX, ""
-	}
-
-	// 1. src type is identical to dst.
-	if types.Identical(src, dst) {
-		return ir.OCONVNOP, ""
-	}
-
-	// 2. src and dst have identical underlying types
-	// and either src or dst is not a named type or
-	// both are empty interface types.
-	// For assignable but different non-empty interface types,
-	// we want to recompute the itab. Recomputing the itab ensures
-	// that itabs are unique (thus an interface with a compile-time
-	// type I has an itab with interface type I).
-	if types.Identical(src.Underlying(), dst.Underlying()) {
-		if src.IsEmptyInterface() {
-			// Conversion between two empty interfaces
-			// requires no code.
-			return ir.OCONVNOP, ""
-		}
-		if (src.Sym() == nil || dst.Sym() == nil) && !src.IsInterface() {
-			// Conversion between two types, at least one unnamed,
-			// needs no conversion. The exception is nonempty interfaces
-			// which need to have their itab updated.
-			return ir.OCONVNOP, ""
-		}
-	}
-
-	// 3. dst is an interface type and src implements dst.
-	if dst.IsInterface() && src.Kind() != types.TNIL {
-		var missing, have *types.Field
-		var ptr int
-		if implements(src, dst, &missing, &have, &ptr) {
-			// Call itabname so that (src, dst)
-			// gets added to itabs early, which allows
-			// us to de-virtualize calls through this
-			// type/interface pair later. See peekitabs in reflect.go
-			if types.IsDirectIface(src) && !dst.IsEmptyInterface() {
-				NeedITab(src, dst)
-			}
-
-			return ir.OCONVIFACE, ""
-		}
-
-		// we'll have complained about this method anyway, suppress spurious messages.
-		if have != nil && have.Sym == missing.Sym && (have.Type.Broke() || missing.Type.Broke()) {
-			return ir.OCONVIFACE, ""
-		}
-
-		var why string
-		if isptrto(src, types.TINTER) {
-			why = fmt.Sprintf(":\n\t%v is pointer to interface, not interface", src)
-		} else if have != nil && have.Sym == missing.Sym && have.Nointerface() {
-			why = fmt.Sprintf(":\n\t%v does not implement %v (%v method is marked 'nointerface')", src, dst, missing.Sym)
-		} else if have != nil && have.Sym == missing.Sym {
-			why = fmt.Sprintf(":\n\t%v does not implement %v (wrong type for %v method)\n"+
-				"\t\thave %v%S\n\t\twant %v%S", src, dst, missing.Sym, have.Sym, have.Type, missing.Sym, missing.Type)
-		} else if ptr != 0 {
-			why = fmt.Sprintf(":\n\t%v does not implement %v (%v method has pointer receiver)", src, dst, missing.Sym)
-		} else if have != nil {
-			why = fmt.Sprintf(":\n\t%v does not implement %v (missing %v method)\n"+
-				"\t\thave %v%S\n\t\twant %v%S", src, dst, missing.Sym, have.Sym, have.Type, missing.Sym, missing.Type)
-		} else {
-			why = fmt.Sprintf(":\n\t%v does not implement %v (missing %v method)", src, dst, missing.Sym)
-		}
-
-		return ir.OXXX, why
-	}
-
-	if isptrto(dst, types.TINTER) {
-		why := fmt.Sprintf(":\n\t%v is pointer to interface, not interface", dst)
-		return ir.OXXX, why
-	}
-
-	if src.IsInterface() && dst.Kind() != types.TBLANK {
-		var missing, have *types.Field
-		var ptr int
-		var why string
-		if implements(dst, src, &missing, &have, &ptr) {
-			why = ": need type assertion"
-		}
-		return ir.OXXX, why
-	}
-
-	// 4. src is a bidirectional channel value, dst is a channel type,
-	// src and dst have identical element types, and
-	// either src or dst is not a named type.
-	if src.IsChan() && src.ChanDir() == types.Cboth && dst.IsChan() {
-		if types.Identical(src.Elem(), dst.Elem()) && (src.Sym() == nil || dst.Sym() == nil) {
-			return ir.OCONVNOP, ""
-		}
-	}
-
-	// 5. src is the predeclared identifier nil and dst is a nillable type.
-	if src.Kind() == types.TNIL {
-		switch dst.Kind() {
-		case types.TPTR,
-			types.TFUNC,
-			types.TMAP,
-			types.TCHAN,
-			types.TINTER,
-			types.TSLICE:
-			return ir.OCONVNOP, ""
-		}
-	}
-
-	// 6. rule about untyped constants - already converted by defaultlit.
-
-	// 7. Any typed value can be assigned to the blank identifier.
-	if dst.Kind() == types.TBLANK {
-		return ir.OCONVNOP, ""
-	}
-
-	return ir.OXXX, ""
-}
-
-// Can we convert a value of type src to a value of type dst?
-// If so, return op code to use in conversion (maybe OCONVNOP).
-// If not, return OXXX. In this case, the string return parameter may
-// hold a reason why. In all other cases, it'll be the empty string.
-// srcConstant indicates whether the value of type src is a constant.
-func convertop(srcConstant bool, src, dst *types.Type) (ir.Op, string) {
-	if src == dst {
-		return ir.OCONVNOP, ""
-	}
-	if src == nil || dst == nil {
-		return ir.OXXX, ""
-	}
-
-	// Conversions from regular to go:notinheap are not allowed
-	// (unless it's unsafe.Pointer). These are runtime-specific
-	// rules.
-	// (a) Disallow (*T) to (*U) where T is go:notinheap but U isn't.
-	if src.IsPtr() && dst.IsPtr() && dst.Elem().NotInHeap() && !src.Elem().NotInHeap() {
-		why := fmt.Sprintf(":\n\t%v is incomplete (or unallocatable), but %v is not", dst.Elem(), src.Elem())
-		return ir.OXXX, why
-	}
-	// (b) Disallow string to []T where T is go:notinheap.
-	if src.IsString() && dst.IsSlice() && dst.Elem().NotInHeap() && (dst.Elem().Kind() == types.ByteType.Kind() || dst.Elem().Kind() == types.RuneType.Kind()) {
-		why := fmt.Sprintf(":\n\t%v is incomplete (or unallocatable)", dst.Elem())
-		return ir.OXXX, why
-	}
-
-	// 1. src can be assigned to dst.
-	op, why := assignop(src, dst)
-	if op != ir.OXXX {
-		return op, why
-	}
-
-	// The rules for interfaces are no different in conversions
-	// than assignments. If interfaces are involved, stop now
-	// with the good message from assignop.
-	// Otherwise clear the error.
-	if src.IsInterface() || dst.IsInterface() {
-		return ir.OXXX, why
-	}
-
-	// 2. Ignoring struct tags, src and dst have identical underlying types.
-	if types.IdenticalIgnoreTags(src.Underlying(), dst.Underlying()) {
-		return ir.OCONVNOP, ""
-	}
-
-	// 3. src and dst are unnamed pointer types and, ignoring struct tags,
-	// their base types have identical underlying types.
-	if src.IsPtr() && dst.IsPtr() && src.Sym() == nil && dst.Sym() == nil {
-		if types.IdenticalIgnoreTags(src.Elem().Underlying(), dst.Elem().Underlying()) {
-			return ir.OCONVNOP, ""
-		}
-	}
-
-	// 4. src and dst are both integer or floating point types.
-	if (src.IsInteger() || src.IsFloat()) && (dst.IsInteger() || dst.IsFloat()) {
-		if types.SimType[src.Kind()] == types.SimType[dst.Kind()] {
-			return ir.OCONVNOP, ""
-		}
-		return ir.OCONV, ""
-	}
-
-	// 5. src and dst are both complex types.
-	if src.IsComplex() && dst.IsComplex() {
-		if types.SimType[src.Kind()] == types.SimType[dst.Kind()] {
-			return ir.OCONVNOP, ""
-		}
-		return ir.OCONV, ""
-	}
-
-	// Special case for constant conversions: any numeric
-	// conversion is potentially okay. We'll validate further
-	// within evconst. See #38117.
-	if srcConstant && (src.IsInteger() || src.IsFloat() || src.IsComplex()) && (dst.IsInteger() || dst.IsFloat() || dst.IsComplex()) {
-		return ir.OCONV, ""
-	}
-
-	// 6. src is an integer or has type []byte or []rune
-	// and dst is a string type.
-	if src.IsInteger() && dst.IsString() {
-		return ir.ORUNESTR, ""
-	}
-
-	if src.IsSlice() && dst.IsString() {
-		if src.Elem().Kind() == types.ByteType.Kind() {
-			return ir.OBYTES2STR, ""
-		}
-		if src.Elem().Kind() == types.RuneType.Kind() {
-			return ir.ORUNES2STR, ""
-		}
-	}
-
-	// 7. src is a string and dst is []byte or []rune.
-	// String to slice.
-	if src.IsString() && dst.IsSlice() {
-		if dst.Elem().Kind() == types.ByteType.Kind() {
-			return ir.OSTR2BYTES, ""
-		}
-		if dst.Elem().Kind() == types.RuneType.Kind() {
-			return ir.OSTR2RUNES, ""
-		}
-	}
-
-	// 8. src is a pointer or uintptr and dst is unsafe.Pointer.
-	if (src.IsPtr() || src.IsUintptr()) && dst.IsUnsafePtr() {
-		return ir.OCONVNOP, ""
-	}
-
-	// 9. src is unsafe.Pointer and dst is a pointer or uintptr.
-	if src.IsUnsafePtr() && (dst.IsPtr() || dst.IsUintptr()) {
-		return ir.OCONVNOP, ""
-	}
-
-	// src is map and dst is a pointer to corresponding hmap.
-	// This rule is needed for the implementation detail that
-	// go gc maps are implemented as a pointer to a hmap struct.
-	if src.Kind() == types.TMAP && dst.IsPtr() &&
-		src.MapType().Hmap == dst.Elem() {
-		return ir.OCONVNOP, ""
-	}
-
-	return ir.OXXX, ""
-}
-
-func assignconv(n ir.Node, t *types.Type, context string) ir.Node {
-	return assignconvfn(n, t, func() string { return context })
-}
-
-// Convert node n for assignment to type t.
-func assignconvfn(n ir.Node, t *types.Type, context func() string) ir.Node {
-	if n == nil || n.Type() == nil || n.Type().Broke() {
-		return n
-	}
-
-	if t.Kind() == types.TBLANK && n.Type().Kind() == types.TNIL {
-		base.Errorf("use of untyped nil")
-	}
-
-	n = convlit1(n, t, false, context)
-	if n.Type() == nil {
-		return n
-	}
-	if t.Kind() == types.TBLANK {
-		return n
-	}
-
-	// Convert ideal bool from comparison to plain bool
-	// if the next step is non-bool (like interface{}).
-	if n.Type() == types.UntypedBool && !t.IsBoolean() {
-		if n.Op() == ir.ONAME || n.Op() == ir.OLITERAL {
-			r := ir.NewConvExpr(base.Pos, ir.OCONVNOP, nil, n)
-			r.SetType(types.Types[types.TBOOL])
-			r.SetTypecheck(1)
-			r.SetImplicit(true)
-			n = r
-		}
-	}
-
-	if types.Identical(n.Type(), t) {
-		return n
-	}
-
-	op, why := assignop(n.Type(), t)
-	if op == ir.OXXX {
-		base.Errorf("cannot use %L as type %v in %s%s", n, t, context(), why)
-		op = ir.OCONV
-	}
-
-	r := ir.NewConvExpr(base.Pos, op, t, n)
-	r.SetTypecheck(1)
-	r.SetImplicit(true)
-	return r
+	typecheck.DotImportRefs = nil
 }
 
 // backingArrayPtrLen extracts the pointer and length from a slice or string.
@@ -475,14 +98,6 @@ func backingArrayPtrLen(n ir.Node) (ptr, length ir.Node) {
 	return ptr, length
 }
 
-func syslook(name string) *ir.Name {
-	s := ir.Pkgs.Runtime.Lookup(name)
-	if s == nil || s.Def == nil {
-		base.Fatalf("syslook: can't find runtime.%s", name)
-	}
-	return ir.AsNode(s.Def).(*ir.Name)
-}
-
 // updateHasCall checks whether expression n contains any function
 // calls and sets the n.HasCall flag if so.
 func updateHasCall(n ir.Node) {
@@ -689,7 +304,7 @@ func safeexpr(n ir.Node, init *ir.Nodes) ir.Node {
 		}
 		a := ir.Copy(n).(*ir.UnaryExpr)
 		a.X = l
-		return walkexpr(typecheck(a, ctxExpr), init)
+		return walkexpr(typecheck.Expr(a), init)
 
 	case ir.ODOT, ir.ODOTPTR:
 		n := n.(*ir.SelectorExpr)
@@ -699,7 +314,7 @@ func safeexpr(n ir.Node, init *ir.Nodes) ir.Node {
 		}
 		a := ir.Copy(n).(*ir.SelectorExpr)
 		a.X = l
-		return walkexpr(typecheck(a, ctxExpr), init)
+		return walkexpr(typecheck.Expr(a), init)
 
 	case ir.ODEREF:
 		n := n.(*ir.StarExpr)
@@ -709,7 +324,7 @@ func safeexpr(n ir.Node, init *ir.Nodes) ir.Node {
 		}
 		a := ir.Copy(n).(*ir.StarExpr)
 		a.X = l
-		return walkexpr(typecheck(a, ctxExpr), init)
+		return walkexpr(typecheck.Expr(a), init)
 
 	case ir.OINDEX, ir.OINDEXMAP:
 		n := n.(*ir.IndexExpr)
@@ -721,7 +336,7 @@ func safeexpr(n ir.Node, init *ir.Nodes) ir.Node {
 		a := ir.Copy(n).(*ir.IndexExpr)
 		a.X = l
 		a.Index = r
-		return walkexpr(typecheck(a, ctxExpr), init)
+		return walkexpr(typecheck.Expr(a), init)
 
 	case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT:
 		n := n.(*ir.CompLitExpr)
@@ -738,7 +353,7 @@ func safeexpr(n ir.Node, init *ir.Nodes) ir.Node {
 }
 
 func copyexpr(n ir.Node, t *types.Type, init *ir.Nodes) ir.Node {
-	l := temp(t)
+	l := typecheck.Temp(t)
 	appendWalkStmt(init, ir.NewAssignStmt(base.Pos, l, n))
 	return l
 }
@@ -754,323 +369,6 @@ func cheapexpr(n ir.Node, init *ir.Nodes) ir.Node {
 	return copyexpr(n, n.Type(), init)
 }
 
-// Code to resolve elided DOTs in embedded types.
-
-// A Dlist stores a pointer to a TFIELD Type embedded within
-// a TSTRUCT or TINTER Type.
-type Dlist struct {
-	field *types.Field
-}
-
-// dotlist is used by adddot1 to record the path of embedded fields
-// used to access a target field or method.
-// Must be non-nil so that dotpath returns a non-nil slice even if d is zero.
-var dotlist = make([]Dlist, 10)
-
-// lookdot0 returns the number of fields or methods named s associated
-// with Type t. If exactly one exists, it will be returned in *save
-// (if save is not nil).
-func lookdot0(s *types.Sym, t *types.Type, save **types.Field, ignorecase bool) int {
-	u := t
-	if u.IsPtr() {
-		u = u.Elem()
-	}
-
-	c := 0
-	if u.IsStruct() || u.IsInterface() {
-		for _, f := range u.Fields().Slice() {
-			if f.Sym == s || (ignorecase && f.IsMethod() && strings.EqualFold(f.Sym.Name, s.Name)) {
-				if save != nil {
-					*save = f
-				}
-				c++
-			}
-		}
-	}
-
-	u = t
-	if t.Sym() != nil && t.IsPtr() && !t.Elem().IsPtr() {
-		// If t is a defined pointer type, then x.m is shorthand for (*x).m.
-		u = t.Elem()
-	}
-	u = types.ReceiverBaseType(u)
-	if u != nil {
-		for _, f := range u.Methods().Slice() {
-			if f.Embedded == 0 && (f.Sym == s || (ignorecase && strings.EqualFold(f.Sym.Name, s.Name))) {
-				if save != nil {
-					*save = f
-				}
-				c++
-			}
-		}
-	}
-
-	return c
-}
-
-// adddot1 returns the number of fields or methods named s at depth d in Type t.
-// If exactly one exists, it will be returned in *save (if save is not nil),
-// and dotlist will contain the path of embedded fields traversed to find it,
-// in reverse order. If none exist, more will indicate whether t contains any
-// embedded fields at depth d, so callers can decide whether to retry at
-// a greater depth.
-func adddot1(s *types.Sym, t *types.Type, d int, save **types.Field, ignorecase bool) (c int, more bool) {
-	if t.Recur() {
-		return
-	}
-	t.SetRecur(true)
-	defer t.SetRecur(false)
-
-	var u *types.Type
-	d--
-	if d < 0 {
-		// We've reached our target depth. If t has any fields/methods
-		// named s, then we're done. Otherwise, we still need to check
-		// below for embedded fields.
-		c = lookdot0(s, t, save, ignorecase)
-		if c != 0 {
-			return c, false
-		}
-	}
-
-	u = t
-	if u.IsPtr() {
-		u = u.Elem()
-	}
-	if !u.IsStruct() && !u.IsInterface() {
-		return c, false
-	}
-
-	for _, f := range u.Fields().Slice() {
-		if f.Embedded == 0 || f.Sym == nil {
-			continue
-		}
-		if d < 0 {
-			// Found an embedded field at target depth.
-			return c, true
-		}
-		a, more1 := adddot1(s, f.Type, d, save, ignorecase)
-		if a != 0 && c == 0 {
-			dotlist[d].field = f
-		}
-		c += a
-		if more1 {
-			more = true
-		}
-	}
-
-	return c, more
-}
-
-// dotpath computes the unique shortest explicit selector path to fully qualify
-// a selection expression x.f, where x is of type t and f is the symbol s.
-// If no such path exists, dotpath returns nil.
-// If there are multiple shortest paths to the same depth, ambig is true.
-func dotpath(s *types.Sym, t *types.Type, save **types.Field, ignorecase bool) (path []Dlist, ambig bool) {
-	// The embedding of types within structs imposes a tree structure onto
-	// types: structs parent the types they embed, and types parent their
-	// fields or methods. Our goal here is to find the shortest path to
-	// a field or method named s in the subtree rooted at t. To accomplish
-	// that, we iteratively perform depth-first searches of increasing depth
-	// until we either find the named field/method or exhaust the tree.
-	for d := 0; ; d++ {
-		if d > len(dotlist) {
-			dotlist = append(dotlist, Dlist{})
-		}
-		if c, more := adddot1(s, t, d, save, ignorecase); c == 1 {
-			return dotlist[:d], false
-		} else if c > 1 {
-			return nil, true
-		} else if !more {
-			return nil, false
-		}
-	}
-}
-
-// in T.field
-// find missing fields that
-// will give shortest unique addressing.
-// modify the tree with missing type names.
-func adddot(n *ir.SelectorExpr) *ir.SelectorExpr {
-	n.X = typecheck(n.X, ctxType|ctxExpr)
-	if n.X.Diag() {
-		n.SetDiag(true)
-	}
-	t := n.X.Type()
-	if t == nil {
-		return n
-	}
-
-	if n.X.Op() == ir.OTYPE {
-		return n
-	}
-
-	s := n.Sel
-	if s == nil {
-		return n
-	}
-
-	switch path, ambig := dotpath(s, t, nil, false); {
-	case path != nil:
-		// rebuild elided dots
-		for c := len(path) - 1; c >= 0; c-- {
-			dot := ir.NewSelectorExpr(base.Pos, ir.ODOT, n.X, path[c].field.Sym)
-			dot.SetImplicit(true)
-			dot.SetType(path[c].field.Type)
-			n.X = dot
-		}
-	case ambig:
-		base.Errorf("ambiguous selector %v", n)
-		n.X = nil
-	}
-
-	return n
-}
-
-// Code to help generate trampoline functions for methods on embedded
-// types. These are approx the same as the corresponding adddot
-// routines except that they expect to be called with unique tasks and
-// they return the actual methods.
-
-type Symlink struct {
-	field *types.Field
-}
-
-var slist []Symlink
-
-func expand0(t *types.Type) {
-	u := t
-	if u.IsPtr() {
-		u = u.Elem()
-	}
-
-	if u.IsInterface() {
-		for _, f := range u.Fields().Slice() {
-			if f.Sym.Uniq() {
-				continue
-			}
-			f.Sym.SetUniq(true)
-			slist = append(slist, Symlink{field: f})
-		}
-
-		return
-	}
-
-	u = types.ReceiverBaseType(t)
-	if u != nil {
-		for _, f := range u.Methods().Slice() {
-			if f.Sym.Uniq() {
-				continue
-			}
-			f.Sym.SetUniq(true)
-			slist = append(slist, Symlink{field: f})
-		}
-	}
-}
-
-func expand1(t *types.Type, top bool) {
-	if t.Recur() {
-		return
-	}
-	t.SetRecur(true)
-
-	if !top {
-		expand0(t)
-	}
-
-	u := t
-	if u.IsPtr() {
-		u = u.Elem()
-	}
-
-	if u.IsStruct() || u.IsInterface() {
-		for _, f := range u.Fields().Slice() {
-			if f.Embedded == 0 {
-				continue
-			}
-			if f.Sym == nil {
-				continue
-			}
-			expand1(f.Type, false)
-		}
-	}
-
-	t.SetRecur(false)
-}
-
-func expandmeth(t *types.Type) {
-	if t == nil || t.AllMethods().Len() != 0 {
-		return
-	}
-
-	// mark top-level method symbols
-	// so that expand1 doesn't consider them.
-	for _, f := range t.Methods().Slice() {
-		f.Sym.SetUniq(true)
-	}
-
-	// generate all reachable methods
-	slist = slist[:0]
-	expand1(t, true)
-
-	// check each method to be uniquely reachable
-	var ms []*types.Field
-	for i, sl := range slist {
-		slist[i].field = nil
-		sl.field.Sym.SetUniq(false)
-
-		var f *types.Field
-		path, _ := dotpath(sl.field.Sym, t, &f, false)
-		if path == nil {
-			continue
-		}
-
-		// dotpath may have dug out arbitrary fields, we only want methods.
-		if !f.IsMethod() {
-			continue
-		}
-
-		// add it to the base type method list
-		f = f.Copy()
-		f.Embedded = 1 // needs a trampoline
-		for _, d := range path {
-			if d.field.Type.IsPtr() {
-				f.Embedded = 2
-				break
-			}
-		}
-		ms = append(ms, f)
-	}
-
-	for _, f := range t.Methods().Slice() {
-		f.Sym.SetUniq(false)
-	}
-
-	ms = append(ms, t.Methods().Slice()...)
-	sort.Sort(types.MethodsByName(ms))
-	t.AllMethods().Set(ms)
-}
-
-// Given funarg struct list, return list of fn args.
-func structargs(tl *types.Type, mustname bool) []*ir.Field {
-	var args []*ir.Field
-	gen := 0
-	for _, t := range tl.Fields().Slice() {
-		s := t.Sym
-		if mustname && (s == nil || s.Name == "_") {
-			// invent a name so that we can refer to it in the trampoline
-			s = lookupN(".anon", gen)
-			gen++
-		}
-		a := ir.NewField(base.Pos, s, nil, t.Type)
-		a.Pos = t.Pos
-		a.IsDDD = t.IsDDD()
-		args = append(args, a)
-	}
-
-	return args
-}
-
 // Generate a wrapper function to convert from
 // a receiver of type T to a receiver of type U.
 // That is,
@@ -1110,14 +408,14 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
 	}
 
 	base.Pos = base.AutogeneratedPos
-	dclcontext = ir.PEXTERN
+	typecheck.DeclContext = ir.PEXTERN
 
 	tfn := ir.NewFuncType(base.Pos,
-		ir.NewField(base.Pos, lookup(".this"), nil, rcvr),
-		structargs(method.Type.Params(), true),
-		structargs(method.Type.Results(), false))
+		ir.NewField(base.Pos, typecheck.Lookup(".this"), nil, rcvr),
+		typecheck.NewFuncParams(method.Type.Params(), true),
+		typecheck.NewFuncParams(method.Type.Results(), false))
 
-	fn := dclfunc(newnam, tfn)
+	fn := typecheck.DeclFunc(newnam, tfn)
 	fn.SetDupok(true)
 
 	nthis := ir.AsNode(tfn.Type().Recv().Nname)
@@ -1128,13 +426,13 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
 	if rcvr.IsPtr() && rcvr.Elem() == methodrcvr {
 		// generating wrapper from *T to T.
 		n := ir.NewIfStmt(base.Pos, nil, nil, nil)
-		n.Cond = ir.NewBinaryExpr(base.Pos, ir.OEQ, nthis, nodnil())
-		call := ir.NewCallExpr(base.Pos, ir.OCALL, syslook("panicwrap"), nil)
+		n.Cond = ir.NewBinaryExpr(base.Pos, ir.OEQ, nthis, typecheck.NodNil())
+		call := ir.NewCallExpr(base.Pos, ir.OCALL, typecheck.LookupRuntime("panicwrap"), nil)
 		n.Body = []ir.Node{call}
 		fn.Body.Append(n)
 	}
 
-	dot := adddot(ir.NewSelectorExpr(base.Pos, ir.OXDOT, nthis, method.Sym))
+	dot := typecheck.AddImplicitDots(ir.NewSelectorExpr(base.Pos, ir.OXDOT, nthis, method.Sym))
 
 	// generate call
 	// It's not possible to use a tail call when dynamic linking on ppc64le. The
@@ -1147,9 +445,9 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
 		// generate tail call: adjust pointer receiver and jump to embedded method.
 		left := dot.X // skip final .M
 		if !left.Type().IsPtr() {
-			left = nodAddr(left)
+			left = typecheck.NodAddr(left)
 		}
-		as := ir.NewAssignStmt(base.Pos, nthis, convnop(left, rcvr))
+		as := ir.NewAssignStmt(base.Pos, nthis, typecheck.ConvNop(left, rcvr))
 		fn.Body.Append(as)
 		fn.Body.Append(ir.NewBranchStmt(base.Pos, ir.ORETJMP, ir.MethodSym(methodrcvr, method.Sym)))
 	} else {
@@ -1170,14 +468,14 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
 		ir.DumpList("genwrapper body", fn.Body)
 	}
 
-	funcbody()
+	typecheck.FinishFuncBody()
 	if base.Debug.DclStack != 0 {
 		types.CheckDclstack()
 	}
 
-	typecheckFunc(fn)
+	typecheck.Func(fn)
 	ir.CurFunc = fn
-	typecheckslice(fn.Body, ctxStmt)
+	typecheck.Stmts(fn.Body)
 
 	// Inline calls within (*T).M wrappers. This is safe because we only
 	// generate those wrappers within the same compilation unit as (T).M.
@@ -1188,15 +486,15 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym) {
 	escapeFuncs([]*ir.Func{fn}, false)
 
 	ir.CurFunc = nil
-	Target.Decls = append(Target.Decls, fn)
+	typecheck.Target.Decls = append(typecheck.Target.Decls, fn)
 }
 
 func hashmem(t *types.Type) ir.Node {
 	sym := ir.Pkgs.Runtime.Lookup("memhash")
 
-	n := NewName(sym)
+	n := typecheck.NewName(sym)
 	ir.MarkFunc(n)
-	n.SetType(functype(nil, []*ir.Field{
+	n.SetType(typecheck.NewFuncType(nil, []*ir.Field{
 		ir.NewField(base.Pos, nil, nil, types.NewPtr(t)),
 		ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR]),
 		ir.NewField(base.Pos, nil, nil, types.Types[types.TUINTPTR]),
@@ -1206,112 +504,6 @@ func hashmem(t *types.Type) ir.Node {
 	return n
 }
 
-func ifacelookdot(s *types.Sym, t *types.Type, ignorecase bool) (m *types.Field, followptr bool) {
-	if t == nil {
-		return nil, false
-	}
-
-	path, ambig := dotpath(s, t, &m, ignorecase)
-	if path == nil {
-		if ambig {
-			base.Errorf("%v.%v is ambiguous", t, s)
-		}
-		return nil, false
-	}
-
-	for _, d := range path {
-		if d.field.Type.IsPtr() {
-			followptr = true
-			break
-		}
-	}
-
-	if !m.IsMethod() {
-		base.Errorf("%v.%v is a field, not a method", t, s)
-		return nil, followptr
-	}
-
-	return m, followptr
-}
-
-func implements(t, iface *types.Type, m, samename **types.Field, ptr *int) bool {
-	t0 := t
-	if t == nil {
-		return false
-	}
-
-	if t.IsInterface() {
-		i := 0
-		tms := t.Fields().Slice()
-		for _, im := range iface.Fields().Slice() {
-			for i < len(tms) && tms[i].Sym != im.Sym {
-				i++
-			}
-			if i == len(tms) {
-				*m = im
-				*samename = nil
-				*ptr = 0
-				return false
-			}
-			tm := tms[i]
-			if !types.Identical(tm.Type, im.Type) {
-				*m = im
-				*samename = tm
-				*ptr = 0
-				return false
-			}
-		}
-
-		return true
-	}
-
-	t = types.ReceiverBaseType(t)
-	var tms []*types.Field
-	if t != nil {
-		expandmeth(t)
-		tms = t.AllMethods().Slice()
-	}
-	i := 0
-	for _, im := range iface.Fields().Slice() {
-		if im.Broke() {
-			continue
-		}
-		for i < len(tms) && tms[i].Sym != im.Sym {
-			i++
-		}
-		if i == len(tms) {
-			*m = im
-			*samename, _ = ifacelookdot(im.Sym, t, true)
-			*ptr = 0
-			return false
-		}
-		tm := tms[i]
-		if tm.Nointerface() || !types.Identical(tm.Type, im.Type) {
-			*m = im
-			*samename = tm
-			*ptr = 0
-			return false
-		}
-		followptr := tm.Embedded == 2
-
-		// if pointer receiver in method,
-		// the method does not exist for value types.
-		rcvr := tm.Type.Recv().Type
-		if rcvr.IsPtr() && !t0.IsPtr() && !followptr && !types.IsInterfaceMethod(tm.Type) {
-			if false && base.Flag.LowerR != 0 {
-				base.Errorf("interface pointer mismatch")
-			}
-
-			*m = im
-			*samename = nil
-			*ptr = 1
-			return false
-		}
-	}
-
-	return true
-}
-
 func ngotype(n ir.Node) *types.Sym {
 	if n.Type() != nil {
 		return typenamesym(n.Type())
diff --git a/src/cmd/compile/internal/gc/swt.go b/src/cmd/compile/internal/gc/swt.go
index 4e7ff00434..9ffa8b67bb 100644
--- a/src/cmd/compile/internal/gc/swt.go
+++ b/src/cmd/compile/internal/gc/swt.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
 	"go/constant"
@@ -14,221 +15,6 @@ import (
 	"sort"
 )
 
-// typecheckswitch typechecks a switch statement.
-func typecheckswitch(n *ir.SwitchStmt) {
-	typecheckslice(n.Init(), ctxStmt)
-	if n.Tag != nil && n.Tag.Op() == ir.OTYPESW {
-		typecheckTypeSwitch(n)
-	} else {
-		typecheckExprSwitch(n)
-	}
-}
-
-func typecheckTypeSwitch(n *ir.SwitchStmt) {
-	guard := n.Tag.(*ir.TypeSwitchGuard)
-	guard.X = typecheck(guard.X, ctxExpr)
-	t := guard.X.Type()
-	if t != nil && !t.IsInterface() {
-		base.ErrorfAt(n.Pos(), "cannot type switch on non-interface value %L", guard.X)
-		t = nil
-	}
-
-	// We don't actually declare the type switch's guarded
-	// declaration itself. So if there are no cases, we won't
-	// notice that it went unused.
-	if v := guard.Tag; v != nil && !ir.IsBlank(v) && len(n.Cases) == 0 {
-		base.ErrorfAt(v.Pos(), "%v declared but not used", v.Sym())
-	}
-
-	var defCase, nilCase ir.Node
-	var ts typeSet
-	for _, ncase := range n.Cases {
-		ncase := ncase.(*ir.CaseStmt)
-		ls := ncase.List
-		if len(ls) == 0 { // default:
-			if defCase != nil {
-				base.ErrorfAt(ncase.Pos(), "multiple defaults in switch (first at %v)", ir.Line(defCase))
-			} else {
-				defCase = ncase
-			}
-		}
-
-		for i := range ls {
-			ls[i] = typecheck(ls[i], ctxExpr|ctxType)
-			n1 := ls[i]
-			if t == nil || n1.Type() == nil {
-				continue
-			}
-
-			var missing, have *types.Field
-			var ptr int
-			if ir.IsNil(n1) { // case nil:
-				if nilCase != nil {
-					base.ErrorfAt(ncase.Pos(), "multiple nil cases in type switch (first at %v)", ir.Line(nilCase))
-				} else {
-					nilCase = ncase
-				}
-				continue
-			}
-			if n1.Op() != ir.OTYPE {
-				base.ErrorfAt(ncase.Pos(), "%L is not a type", n1)
-				continue
-			}
-			if !n1.Type().IsInterface() && !implements(n1.Type(), t, &missing, &have, &ptr) && !missing.Broke() {
-				if have != nil && !have.Broke() {
-					base.ErrorfAt(ncase.Pos(), "impossible type switch case: %L cannot have dynamic type %v"+
-						" (wrong type for %v method)\n\thave %v%S\n\twant %v%S", guard.X, n1.Type(), missing.Sym, have.Sym, have.Type, missing.Sym, missing.Type)
-				} else if ptr != 0 {
-					base.ErrorfAt(ncase.Pos(), "impossible type switch case: %L cannot have dynamic type %v"+
-						" (%v method has pointer receiver)", guard.X, n1.Type(), missing.Sym)
-				} else {
-					base.ErrorfAt(ncase.Pos(), "impossible type switch case: %L cannot have dynamic type %v"+
-						" (missing %v method)", guard.X, n1.Type(), missing.Sym)
-				}
-				continue
-			}
-
-			ts.add(ncase.Pos(), n1.Type())
-		}
-
-		if len(ncase.Vars) != 0 {
-			// Assign the clause variable's type.
-			vt := t
-			if len(ls) == 1 {
-				if ls[0].Op() == ir.OTYPE {
-					vt = ls[0].Type()
-				} else if !ir.IsNil(ls[0]) {
-					// Invalid single-type case;
-					// mark variable as broken.
-					vt = nil
-				}
-			}
-
-			nvar := ncase.Vars[0]
-			nvar.SetType(vt)
-			if vt != nil {
-				nvar = typecheck(nvar, ctxExpr|ctxAssign)
-			} else {
-				// Clause variable is broken; prevent typechecking.
-				nvar.SetTypecheck(1)
-				nvar.SetWalkdef(1)
-			}
-			ncase.Vars[0] = nvar
-		}
-
-		typecheckslice(ncase.Body, ctxStmt)
-	}
-}
-
-type typeSet struct {
-	m map[string][]typeSetEntry
-}
-
-type typeSetEntry struct {
-	pos src.XPos
-	typ *types.Type
-}
-
-func (s *typeSet) add(pos src.XPos, typ *types.Type) {
-	if s.m == nil {
-		s.m = make(map[string][]typeSetEntry)
-	}
-
-	// LongString does not uniquely identify types, so we need to
-	// disambiguate collisions with types.Identical.
-	// TODO(mdempsky): Add a method that *is* unique.
-	ls := typ.LongString()
-	prevs := s.m[ls]
-	for _, prev := range prevs {
-		if types.Identical(typ, prev.typ) {
-			base.ErrorfAt(pos, "duplicate case %v in type switch\n\tprevious case at %s", typ, base.FmtPos(prev.pos))
-			return
-		}
-	}
-	s.m[ls] = append(prevs, typeSetEntry{pos, typ})
-}
-
-func typecheckExprSwitch(n *ir.SwitchStmt) {
-	t := types.Types[types.TBOOL]
-	if n.Tag != nil {
-		n.Tag = typecheck(n.Tag, ctxExpr)
-		n.Tag = defaultlit(n.Tag, nil)
-		t = n.Tag.Type()
-	}
-
-	var nilonly string
-	if t != nil {
-		switch {
-		case t.IsMap():
-			nilonly = "map"
-		case t.Kind() == types.TFUNC:
-			nilonly = "func"
-		case t.IsSlice():
-			nilonly = "slice"
-
-		case !types.IsComparable(t):
-			if t.IsStruct() {
-				base.ErrorfAt(n.Pos(), "cannot switch on %L (struct containing %v cannot be compared)", n.Tag, types.IncomparableField(t).Type)
-			} else {
-				base.ErrorfAt(n.Pos(), "cannot switch on %L", n.Tag)
-			}
-			t = nil
-		}
-	}
-
-	var defCase ir.Node
-	var cs constSet
-	for _, ncase := range n.Cases {
-		ncase := ncase.(*ir.CaseStmt)
-		ls := ncase.List
-		if len(ls) == 0 { // default:
-			if defCase != nil {
-				base.ErrorfAt(ncase.Pos(), "multiple defaults in switch (first at %v)", ir.Line(defCase))
-			} else {
-				defCase = ncase
-			}
-		}
-
-		for i := range ls {
-			ir.SetPos(ncase)
-			ls[i] = typecheck(ls[i], ctxExpr)
-			ls[i] = defaultlit(ls[i], t)
-			n1 := ls[i]
-			if t == nil || n1.Type() == nil {
-				continue
-			}
-
-			if nilonly != "" && !ir.IsNil(n1) {
-				base.ErrorfAt(ncase.Pos(), "invalid case %v in switch (can only compare %s %v to nil)", n1, nilonly, n.Tag)
-			} else if t.IsInterface() && !n1.Type().IsInterface() && !types.IsComparable(n1.Type()) {
-				base.ErrorfAt(ncase.Pos(), "invalid case %L in switch (incomparable type)", n1)
-			} else {
-				op1, _ := assignop(n1.Type(), t)
-				op2, _ := assignop(t, n1.Type())
-				if op1 == ir.OXXX && op2 == ir.OXXX {
-					if n.Tag != nil {
-						base.ErrorfAt(ncase.Pos(), "invalid case %v in switch on %v (mismatched types %v and %v)", n1, n.Tag, n1.Type(), t)
-					} else {
-						base.ErrorfAt(ncase.Pos(), "invalid case %v in switch (mismatched types %v and bool)", n1, n1.Type())
-					}
-				}
-			}
-
-			// Don't check for duplicate bools. Although the spec allows it,
-			// (1) the compiler hasn't checked it in the past, so compatibility mandates it, and
-			// (2) it would disallow useful things like
-			//       case GOARCH == "arm" && GOARM == "5":
-			//       case GOARCH == "arm":
-			//     which would both evaluate to false for non-ARM compiles.
-			if !n1.Type().IsBoolean() {
-				cs.add(ncase.Pos(), n1, "case", "switch")
-			}
-		}
-
-		typecheckslice(ncase.Body, ctxStmt)
-	}
-}
-
 // walkswitch walks a switch statement.
 func walkswitch(sw *ir.SwitchStmt) {
 	// Guard against double walk, see #25776.
@@ -254,8 +40,8 @@ func walkExprSwitch(sw *ir.SwitchStmt) {
 	// convert switch {...} to switch true {...}
 	if cond == nil {
 		cond = ir.NewBool(true)
-		cond = typecheck(cond, ctxExpr)
-		cond = defaultlit(cond, nil)
+		cond = typecheck.Expr(cond)
+		cond = typecheck.DefaultLit(cond, nil)
 	}
 
 	// Given "switch string(byteslice)",
@@ -285,7 +71,7 @@ func walkExprSwitch(sw *ir.SwitchStmt) {
 	var body ir.Nodes
 	for _, ncase := range sw.Cases {
 		ncase := ncase.(*ir.CaseStmt)
-		label := autolabel(".s")
+		label := typecheck.AutoLabel(".s")
 		jmp := ir.NewBranchStmt(ncase.Pos(), ir.OGOTO, label)
 
 		// Process case dispatch.
@@ -509,7 +295,7 @@ func walkTypeSwitch(sw *ir.SwitchStmt) {
 
 	s.facename = walkexpr(s.facename, sw.PtrInit())
 	s.facename = copyexpr(s.facename, s.facename.Type(), &sw.Compiled)
-	s.okname = temp(types.Types[types.TBOOL])
+	s.okname = typecheck.Temp(types.Types[types.TBOOL])
 
 	// Get interface descriptor word.
 	// For empty interfaces this will be the type.
@@ -523,10 +309,10 @@ func walkTypeSwitch(sw *ir.SwitchStmt) {
 	//     h := e._type.hash
 	// Use a similar strategy for non-empty interfaces.
 	ifNil := ir.NewIfStmt(base.Pos, nil, nil, nil)
-	ifNil.Cond = ir.NewBinaryExpr(base.Pos, ir.OEQ, itab, nodnil())
+	ifNil.Cond = ir.NewBinaryExpr(base.Pos, ir.OEQ, itab, typecheck.NodNil())
 	base.Pos = base.Pos.WithNotStmt() // disable statement marks after the first check.
-	ifNil.Cond = typecheck(ifNil.Cond, ctxExpr)
-	ifNil.Cond = defaultlit(ifNil.Cond, nil)
+	ifNil.Cond = typecheck.Expr(ifNil.Cond)
+	ifNil.Cond = typecheck.DefaultLit(ifNil.Cond, nil)
 	// ifNil.Nbody assigned at end.
 	sw.Compiled.Append(ifNil)
 
@@ -561,7 +347,7 @@ func walkTypeSwitch(sw *ir.SwitchStmt) {
 		}
 		caseVarInitialized := false
 
-		label := autolabel(".s")
+		label := typecheck.AutoLabel(".s")
 		jmp := ir.NewBranchStmt(ncase.Pos(), ir.OGOTO, label)
 
 		if len(ncase.List) == 0 { // default:
@@ -602,7 +388,7 @@ func walkTypeSwitch(sw *ir.SwitchStmt) {
 				ir.NewDecl(ncase.Pos(), ir.ODCL, caseVar),
 				ir.NewAssignStmt(ncase.Pos(), caseVar, val),
 			}
-			typecheckslice(l, ctxStmt)
+			typecheck.Stmts(l)
 			body.Append(l...)
 		}
 		body.Append(ncase.Body...)
@@ -648,7 +434,7 @@ func (s *typeSwitch) Add(pos src.XPos, typ *types.Type, caseVar, jmp ir.Node) {
 			ir.NewDecl(pos, ir.ODCL, caseVar),
 			ir.NewAssignStmt(pos, caseVar, nil),
 		}
-		typecheckslice(l, ctxStmt)
+		typecheck.Stmts(l)
 		body.Append(l...)
 	} else {
 		caseVar = ir.BlankNode
@@ -740,8 +526,8 @@ func binarySearch(n int, out *ir.Nodes, less func(i int) ir.Node, leaf func(i in
 				nif := ir.NewIfStmt(base.Pos, nil, nil, nil)
 				leaf(i, nif)
 				base.Pos = base.Pos.WithNotStmt()
-				nif.Cond = typecheck(nif.Cond, ctxExpr)
-				nif.Cond = defaultlit(nif.Cond, nil)
+				nif.Cond = typecheck.Expr(nif.Cond)
+				nif.Cond = typecheck.DefaultLit(nif.Cond, nil)
 				out.Append(nif)
 				out = &nif.Else
 			}
@@ -752,8 +538,8 @@ func binarySearch(n int, out *ir.Nodes, less func(i int) ir.Node, leaf func(i in
 		nif := ir.NewIfStmt(base.Pos, nil, nil, nil)
 		nif.Cond = less(half)
 		base.Pos = base.Pos.WithNotStmt()
-		nif.Cond = typecheck(nif.Cond, ctxExpr)
-		nif.Cond = defaultlit(nif.Cond, nil)
+		nif.Cond = typecheck.Expr(nif.Cond)
+		nif.Cond = typecheck.DefaultLit(nif.Cond, nil)
 		do(lo, half, &nif.Body)
 		do(half, hi, &nif.Else)
 		out.Append(nif)
diff --git a/src/cmd/compile/internal/gc/types_acc.go b/src/cmd/compile/internal/gc/types_acc.go
deleted file mode 100644
index d6d53f05cc..0000000000
--- a/src/cmd/compile/internal/gc/types_acc.go
+++ /dev/null
@@ -1,8 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file implements convertions between *types.Node and *Node.
-// TODO(gri) try to eliminate these soon
-
-package gc
diff --git a/src/cmd/compile/internal/gc/unsafe.go b/src/cmd/compile/internal/gc/unsafe.go
deleted file mode 100644
index d37ebfff31..0000000000
--- a/src/cmd/compile/internal/gc/unsafe.go
+++ /dev/null
@@ -1,90 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package gc
-
-import (
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/types"
-)
-
-// evalunsafe evaluates a package unsafe operation and returns the result.
-func evalunsafe(n ir.Node) int64 {
-	switch n.Op() {
-	case ir.OALIGNOF, ir.OSIZEOF:
-		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
-		n.X = defaultlit(n.X, nil)
-		tr := n.X.Type()
-		if tr == nil {
-			return 0
-		}
-		types.CalcSize(tr)
-		if n.Op() == ir.OALIGNOF {
-			return int64(tr.Align)
-		}
-		return tr.Width
-
-	case ir.OOFFSETOF:
-		// must be a selector.
-		n := n.(*ir.UnaryExpr)
-		if n.X.Op() != ir.OXDOT {
-			base.Errorf("invalid expression %v", n)
-			return 0
-		}
-		sel := n.X.(*ir.SelectorExpr)
-
-		// Remember base of selector to find it back after dot insertion.
-		// Since r->left may be mutated by typechecking, check it explicitly
-		// first to track it correctly.
-		sel.X = typecheck(sel.X, ctxExpr)
-		sbase := sel.X
-
-		tsel := typecheck(sel, ctxExpr)
-		n.X = tsel
-		if tsel.Type() == nil {
-			return 0
-		}
-		switch tsel.Op() {
-		case ir.ODOT, ir.ODOTPTR:
-			break
-		case ir.OCALLPART:
-			base.Errorf("invalid expression %v: argument is a method value", n)
-			return 0
-		default:
-			base.Errorf("invalid expression %v", n)
-			return 0
-		}
-
-		// Sum offsets for dots until we reach sbase.
-		var v int64
-		var next ir.Node
-		for r := tsel; r != sbase; r = next {
-			switch r.Op() {
-			case ir.ODOTPTR:
-				// For Offsetof(s.f), s may itself be a pointer,
-				// but accessing f must not otherwise involve
-				// indirection via embedded pointer types.
-				r := r.(*ir.SelectorExpr)
-				if r.X != sbase {
-					base.Errorf("invalid expression %v: selector implies indirection of embedded %v", n, r.X)
-					return 0
-				}
-				fallthrough
-			case ir.ODOT:
-				r := r.(*ir.SelectorExpr)
-				v += r.Offset
-				next = r.X
-			default:
-				ir.Dump("unsafenmagic", tsel)
-				base.Fatalf("impossible %v node after dot insertion", r.Op())
-			}
-		}
-		return v
-	}
-
-	base.Fatalf("unexpected op %v", n.Op())
-	return 0
-}
diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index 764c5c41b0..73f82f333c 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
+	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/objabi"
@@ -42,7 +43,7 @@ func walk(fn *ir.Func) {
 	// Final typecheck for any unused variables.
 	for i, ln := range fn.Dcl {
 		if ln.Op() == ir.ONAME && (ln.Class_ == ir.PAUTO || ln.Class_ == ir.PAUTOHEAP) {
-			ln = typecheck(ln, ctxExpr|ctxAssign).(*ir.Name)
+			ln = typecheck.AssignExpr(ln).(*ir.Name)
 			fn.Dcl[i] = ln
 		}
 	}
@@ -191,7 +192,7 @@ func walkstmt(n ir.Node) ir.Node {
 		n.PtrInit().Set(nil)
 
 		n.X = walkexpr(n.X, &init)
-		call := walkexpr(mkcall1(chanfn("chanrecv1", 2, n.X.Type()), nil, &init, n.X, nodnil()), &init)
+		call := walkexpr(mkcall1(chanfn("chanrecv1", 2, n.X.Type()), nil, &init, n.X, typecheck.NodNil()), &init)
 		return ir.InitExpr(init, call)
 
 	case ir.OBREAK,
@@ -216,7 +217,7 @@ func walkstmt(n ir.Node) ir.Node {
 			}
 			nn := ir.NewAssignStmt(base.Pos, v.Name().Heapaddr, callnew(v.Type()))
 			nn.Def = true
-			return walkstmt(typecheck(nn, ctxStmt))
+			return walkstmt(typecheck.Stmt(nn))
 		}
 		return n
 
@@ -325,7 +326,7 @@ func walkstmt(n ir.Node) ir.Node {
 				if cl == ir.PPARAMOUT {
 					var ln ir.Node = ln
 					if ir.IsParamStackCopy(ln) {
-						ln = walkexpr(typecheck(ir.NewStarExpr(base.Pos, ln.Name().Heapaddr), ctxExpr), nil)
+						ln = walkexpr(typecheck.Expr(ir.NewStarExpr(base.Pos, ln.Name().Heapaddr)), nil)
 					}
 					rl = append(rl, ln)
 				}
@@ -504,7 +505,7 @@ func walkexpr(n ir.Node, init *ir.Nodes) ir.Node {
 		n := n.(*ir.Name)
 		nn := ir.NewStarExpr(base.Pos, n.Name().Heapaddr)
 		nn.X.MarkNonNil()
-		return walkexpr(typecheck(nn, ctxExpr), init)
+		return walkexpr(typecheck.Expr(nn), init)
 	}
 
 	n = walkexpr1(n, init)
@@ -515,12 +516,12 @@ func walkexpr(n ir.Node, init *ir.Nodes) ir.Node {
 	// walk of y%1 may have replaced it by 0.
 	// Check whether n with its updated args is itself now a constant.
 	t := n.Type()
-	n = evalConst(n)
+	n = typecheck.EvalConst(n)
 	if n.Type() != t {
 		base.Fatalf("evconst changed Type: %v had type %v, now %v", n, t, n.Type())
 	}
 	if n.Op() == ir.OLITERAL {
-		n = typecheck(n, ctxExpr)
+		n = typecheck.Expr(n)
 		// Emit string symbol now to avoid emitting
 		// any concurrently during the backend.
 		if v := n.Val(); v.Kind() == constant.String {
@@ -604,7 +605,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		n := n.(*ir.UnaryExpr)
 		if isRuneCount(n) {
 			// Replace len([]rune(string)) with runtime.countrunes(string).
-			return mkcall("countrunes", n.Type(), init, conv(n.X.(*ir.ConvExpr).X, types.Types[types.TSTRING]))
+			return mkcall("countrunes", n.Type(), init, typecheck.Conv(n.X.(*ir.ConvExpr).X, types.Types[types.TSTRING]))
 		}
 
 		n.X = walkexpr(n.X, init)
@@ -618,7 +619,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		}
 		if t.IsArray() {
 			safeexpr(n.X, init)
-			con := origIntConst(n, t.NumElem())
+			con := typecheck.OrigInt(n, t.NumElem())
 			con.SetTypecheck(1)
 			return con
 		}
@@ -656,7 +657,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 
 	case ir.ORECOVER:
 		n := n.(*ir.CallExpr)
-		return mkcall("gorecover", n.Type(), init, nodAddr(ir.RegFP))
+		return mkcall("gorecover", n.Type(), init, typecheck.NodAddr(ir.RegFP))
 
 	case ir.OCLOSUREREAD, ir.OCFUNC:
 		return n
@@ -724,7 +725,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 
 		if n.Op() == ir.OASOP {
 			// Rewrite x op= y into x = x op y.
-			n = ir.NewAssignStmt(base.Pos, left, typecheck(ir.NewBinaryExpr(base.Pos, n.(*ir.AssignOpStmt).AsOp, left, right), ctxExpr))
+			n = ir.NewAssignStmt(base.Pos, left, typecheck.Expr(ir.NewBinaryExpr(base.Pos, n.(*ir.AssignOpStmt).AsOp, left, right)))
 		} else {
 			n.(*ir.AssignStmt).X = left
 		}
@@ -753,7 +754,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			recv := as.Y.(*ir.UnaryExpr)
 			recv.X = walkexpr(recv.X, init)
 
-			n1 := nodAddr(as.X)
+			n1 := typecheck.NodAddr(as.X)
 			r := recv.X // the channel
 			return mkcall1(chanfn("chanrecv1", 2, r.Type()), nil, init, r, n1)
 
@@ -826,14 +827,14 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		r.X = walkexpr(r.X, init)
 		var n1 ir.Node
 		if ir.IsBlank(n.Lhs[0]) {
-			n1 = nodnil()
+			n1 = typecheck.NodNil()
 		} else {
-			n1 = nodAddr(n.Lhs[0])
+			n1 = typecheck.NodAddr(n.Lhs[0])
 		}
 		fn := chanfn("chanrecv2", 2, r.X.Type())
 		ok := n.Lhs[1]
 		call := mkcall1(fn, types.Types[types.TBOOL], init, r.X, n1)
-		return typecheck(ir.NewAssignStmt(base.Pos, ok, call), ctxStmt)
+		return typecheck.Stmt(ir.NewAssignStmt(base.Pos, ok, call))
 
 	// a,b = m[i]
 	case ir.OAS2MAPR:
@@ -854,7 +855,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		} else {
 			// standard version takes key by reference
 			// order.expr made sure key is addressable.
-			key = nodAddr(r.Index)
+			key = typecheck.NodAddr(r.Index)
 		}
 
 		// from:
@@ -885,10 +886,10 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 
 		// don't generate a = *var if a is _
 		if ir.IsBlank(a) {
-			return walkexpr(typecheck(n, ctxStmt), init)
+			return walkexpr(typecheck.Stmt(n), init)
 		}
 
-		var_ := temp(types.NewPtr(t.Elem()))
+		var_ := typecheck.Temp(types.NewPtr(t.Elem()))
 		var_.SetTypecheck(1)
 		var_.MarkNonNil() // mapaccess always returns a non-nil pointer
 
@@ -896,7 +897,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		init.Append(walkexpr(n, init))
 
 		as := ir.NewAssignStmt(base.Pos, a, ir.NewStarExpr(base.Pos, var_))
-		return walkexpr(typecheck(as, ctxStmt), init)
+		return walkexpr(typecheck.Stmt(as), init)
 
 	case ir.ODELETE:
 		n := n.(*ir.CallExpr)
@@ -910,7 +911,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		fast := mapfast(t)
 		if fast == mapslow {
 			// order.stmt made sure key is addressable.
-			key = nodAddr(key)
+			key = typecheck.NodAddr(key)
 		}
 		return mkcall1(mapfndel(mapdelete[fast], t), nil, init, typename(t), map_, key)
 
@@ -948,12 +949,12 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		}
 
 		if ir.Names.Staticuint64s == nil {
-			ir.Names.Staticuint64s = NewName(ir.Pkgs.Runtime.Lookup("staticuint64s"))
+			ir.Names.Staticuint64s = typecheck.NewName(ir.Pkgs.Runtime.Lookup("staticuint64s"))
 			ir.Names.Staticuint64s.Class_ = ir.PEXTERN
 			// The actual type is [256]uint64, but we use [256*8]uint8 so we can address
 			// individual bytes.
 			ir.Names.Staticuint64s.SetType(types.NewArray(types.Types[types.TUINT8], 256*8))
-			ir.Names.Zerobase = NewName(ir.Pkgs.Runtime.Lookup("zerobase"))
+			ir.Names.Zerobase = typecheck.NewName(ir.Pkgs.Runtime.Lookup("zerobase"))
 			ir.Names.Zerobase.Class_ = ir.PEXTERN
 			ir.Names.Zerobase.SetType(types.Types[types.TUINTPTR])
 		}
@@ -984,14 +985,14 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			value = n.X
 		case !fromType.IsInterface() && n.Esc() == ir.EscNone && fromType.Width <= 1024:
 			// n.Left does not escape. Use a stack temporary initialized to n.Left.
-			value = temp(fromType)
-			init.Append(typecheck(ir.NewAssignStmt(base.Pos, value, n.X), ctxStmt))
+			value = typecheck.Temp(fromType)
+			init.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, value, n.X)))
 		}
 
 		if value != nil {
 			// Value is identical to n.Left.
 			// Construct the interface directly: {type/itab, &value}.
-			l := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeword(), typecheck(nodAddr(value), ctxExpr))
+			l := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeword(), typecheck.Expr(typecheck.NodAddr(value)))
 			l.SetType(toType)
 			l.SetTypecheck(n.Typecheck())
 			return l
@@ -1005,15 +1006,15 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		// e = iface{tmp, i.data}
 		if toType.IsEmptyInterface() && fromType.IsInterface() && !fromType.IsEmptyInterface() {
 			// Evaluate the input interface.
-			c := temp(fromType)
+			c := typecheck.Temp(fromType)
 			init.Append(ir.NewAssignStmt(base.Pos, c, n.X))
 
 			// Get the itab out of the interface.
-			tmp := temp(types.NewPtr(types.Types[types.TUINT8]))
-			init.Append(ir.NewAssignStmt(base.Pos, tmp, typecheck(ir.NewUnaryExpr(base.Pos, ir.OITAB, c), ctxExpr)))
+			tmp := typecheck.Temp(types.NewPtr(types.Types[types.TUINT8]))
+			init.Append(ir.NewAssignStmt(base.Pos, tmp, typecheck.Expr(ir.NewUnaryExpr(base.Pos, ir.OITAB, c))))
 
 			// Get the type out of the itab.
-			nif := ir.NewIfStmt(base.Pos, typecheck(ir.NewBinaryExpr(base.Pos, ir.ONE, tmp, nodnil()), ctxExpr), nil, nil)
+			nif := ir.NewIfStmt(base.Pos, typecheck.Expr(ir.NewBinaryExpr(base.Pos, ir.ONE, tmp, typecheck.NodNil())), nil, nil)
 			nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, tmp, itabType(tmp))}
 			init.Append(nif)
 
@@ -1030,13 +1031,13 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			// Use a specialized conversion routine that only returns a data pointer.
 			// ptr = convT2X(val)
 			// e = iface{typ/tab, ptr}
-			fn := syslook(fnname)
+			fn := typecheck.LookupRuntime(fnname)
 			types.CalcSize(fromType)
-			fn = substArgTypes(fn, fromType)
+			fn = typecheck.SubstArgTypes(fn, fromType)
 			types.CalcSize(fn.Type())
 			call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
 			call.Args = []ir.Node{n.X}
-			e := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeword(), safeexpr(walkexpr(typecheck(call, ctxExpr), init), init))
+			e := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeword(), safeexpr(walkexpr(typecheck.Expr(call), init), init))
 			e.SetType(toType)
 			e.SetTypecheck(1)
 			return e
@@ -1062,16 +1063,16 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			if !ir.IsAssignable(v) {
 				v = copyexpr(v, v.Type(), init)
 			}
-			v = nodAddr(v)
+			v = typecheck.NodAddr(v)
 		}
 
 		types.CalcSize(fromType)
-		fn := syslook(fnname)
-		fn = substArgTypes(fn, fromType, toType)
+		fn := typecheck.LookupRuntime(fnname)
+		fn = typecheck.SubstArgTypes(fn, fromType, toType)
 		types.CalcSize(fn.Type())
 		call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
 		call.Args = []ir.Node{tab, v}
-		return walkexpr(typecheck(call, ctxExpr), init)
+		return walkexpr(typecheck.Expr(call), init)
 
 	case ir.OCONV, ir.OCONVNOP:
 		n := n.(*ir.ConvExpr)
@@ -1092,7 +1093,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			return n
 		}
 		fn := types.BasicTypeNames[param] + "to" + types.BasicTypeNames[result]
-		return conv(mkcall(fn, types.Types[result], init, conv(n.X, types.Types[param])), n.Type())
+		return typecheck.Conv(mkcall(fn, types.Types[result], init, typecheck.Conv(n.X, types.Types[param])), n.Type())
 
 	case ir.ODIV, ir.OMOD:
 		n := n.(*ir.BinaryExpr)
@@ -1104,8 +1105,8 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 
 		if types.IsComplex[et] && n.Op() == ir.ODIV {
 			t := n.Type()
-			call := mkcall("complex128div", types.Types[types.TCOMPLEX128], init, conv(n.X, types.Types[types.TCOMPLEX128]), conv(n.Y, types.Types[types.TCOMPLEX128]))
-			return conv(call, t)
+			call := mkcall("complex128div", types.Types[types.TCOMPLEX128], init, typecheck.Conv(n.X, types.Types[types.TCOMPLEX128]), typecheck.Conv(n.Y, types.Types[types.TCOMPLEX128]))
+			return typecheck.Conv(call, t)
 		}
 
 		// Nothing to do for float divisions.
@@ -1150,7 +1151,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			} else {
 				fn += "mod"
 			}
-			return mkcall(fn, n.Type(), init, conv(n.X, types.Types[et]), conv(n.Y, types.Types[et]))
+			return mkcall(fn, n.Type(), init, typecheck.Conv(n.X, types.Types[et]), typecheck.Conv(n.Y, types.Types[et]))
 		}
 		return n
 
@@ -1213,7 +1214,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			if fast == mapslow {
 				// standard version takes key by reference.
 				// order.expr made sure key is addressable.
-				key = nodAddr(key)
+				key = typecheck.NodAddr(key)
 			}
 			call = mkcall1(mapfn(mapassign[fast], t), nil, init, typename(t), map_, key)
 		} else {
@@ -1222,7 +1223,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			if fast == mapslow {
 				// standard version takes key by reference.
 				// order.expr made sure key is addressable.
-				key = nodAddr(key)
+				key = typecheck.NodAddr(key)
 			}
 
 			if w := t.Elem().Width; w <= zeroValSize {
@@ -1297,9 +1298,9 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			if n.Type().Elem().Width >= ir.MaxImplicitStackVarSize {
 				base.Fatalf("large ONEW with EscNone: %v", n)
 			}
-			r := temp(n.Type().Elem())
-			init.Append(typecheck(ir.NewAssignStmt(base.Pos, r, nil), ctxStmt)) // zero temp
-			return typecheck(nodAddr(r), ctxExpr)
+			r := typecheck.Temp(n.Type().Elem())
+			init.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, r, nil))) // zero temp
+			return typecheck.Expr(typecheck.NodAddr(r))
 		}
 		return callnew(n.Type().Elem())
 
@@ -1317,8 +1318,8 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 	case ir.OCLOSE:
 		// cannot use chanfn - closechan takes any, not chan any
 		n := n.(*ir.UnaryExpr)
-		fn := syslook("closechan")
-		fn = substArgTypes(fn, n.X.Type())
+		fn := typecheck.LookupRuntime("closechan")
+		fn = typecheck.SubstArgTypes(fn, n.X.Type())
 		return mkcall1(fn, nil, init, n.X)
 
 	case ir.OMAKECHAN:
@@ -1337,7 +1338,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			argtype = types.Types[types.TINT]
 		}
 
-		return mkcall1(chanfn(fnname, 1, n.Type()), n.Type(), init, typename(n.Type()), conv(size, argtype))
+		return mkcall1(chanfn(fnname, 1, n.Type()), n.Type(), init, typename(n.Type()), typecheck.Conv(size, argtype))
 
 	case ir.OMAKEMAP:
 		n := n.(*ir.MakeExpr)
@@ -1351,10 +1352,10 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			// Allocate hmap on stack.
 
 			// var hv hmap
-			hv := temp(hmapType)
-			init.Append(typecheck(ir.NewAssignStmt(base.Pos, hv, nil), ctxStmt))
+			hv := typecheck.Temp(hmapType)
+			init.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, hv, nil)))
 			// h = &hv
-			h = nodAddr(hv)
+			h = typecheck.NodAddr(hv)
 
 			// Allocate one bucket pointed to by hmap.buckets on stack if hint
 			// is not larger than BUCKETSIZE. In case hint is larger than
@@ -1377,11 +1378,11 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 				nif.Likely = true
 
 				// var bv bmap
-				bv := temp(bmap(t))
+				bv := typecheck.Temp(bmap(t))
 				nif.Body.Append(ir.NewAssignStmt(base.Pos, bv, nil))
 
 				// b = &bv
-				b := nodAddr(bv)
+				b := typecheck.NodAddr(bv)
 
 				// h.buckets = b
 				bsym := hmapType.Field(5).Sym // hmap.buckets see reflect.go:hmap
@@ -1406,17 +1407,17 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 				rand := mkcall("fastrand", types.Types[types.TUINT32], init)
 				hashsym := hmapType.Field(4).Sym // hmap.hash0 see reflect.go:hmap
 				appendWalkStmt(init, ir.NewAssignStmt(base.Pos, ir.NewSelectorExpr(base.Pos, ir.ODOT, h, hashsym), rand))
-				return convnop(h, t)
+				return typecheck.ConvNop(h, t)
 			}
 			// Call runtime.makehmap to allocate an
 			// hmap on the heap and initialize hmap's hash0 field.
-			fn := syslook("makemap_small")
-			fn = substArgTypes(fn, t.Key(), t.Elem())
+			fn := typecheck.LookupRuntime("makemap_small")
+			fn = typecheck.SubstArgTypes(fn, t.Key(), t.Elem())
 			return mkcall1(fn, n.Type(), init)
 		}
 
 		if n.Esc() != ir.EscNone {
-			h = nodnil()
+			h = typecheck.NodNil()
 		}
 		// Map initialization with a variable or large hint is
 		// more complicated. We therefore generate a call to
@@ -1437,9 +1438,9 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			argtype = types.Types[types.TINT]
 		}
 
-		fn := syslook(fnname)
-		fn = substArgTypes(fn, hmapType, t.Key(), t.Elem())
-		return mkcall1(fn, n.Type(), init, typename(n.Type()), conv(hint, argtype), h)
+		fn := typecheck.LookupRuntime(fnname)
+		fn = typecheck.SubstArgTypes(fn, hmapType, t.Key(), t.Elem())
+		return mkcall1(fn, n.Type(), init, typename(n.Type()), typecheck.Conv(hint, argtype), h)
 
 	case ir.OMAKESLICE:
 		n := n.(*ir.MakeExpr)
@@ -1459,7 +1460,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			}
 			// var arr [r]T
 			// n = arr[:l]
-			i := indexconst(r)
+			i := typecheck.IndexConst(r)
 			if i < 0 {
 				base.Fatalf("walkexpr: invalid index %v", r)
 			}
@@ -1471,19 +1472,19 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			//     if len < 0 { panicmakeslicelen() }
 			//     panicmakeslicecap()
 			// }
-			nif := ir.NewIfStmt(base.Pos, ir.NewBinaryExpr(base.Pos, ir.OGT, conv(l, types.Types[types.TUINT64]), ir.NewInt(i)), nil, nil)
+			nif := ir.NewIfStmt(base.Pos, ir.NewBinaryExpr(base.Pos, ir.OGT, typecheck.Conv(l, types.Types[types.TUINT64]), ir.NewInt(i)), nil, nil)
 			niflen := ir.NewIfStmt(base.Pos, ir.NewBinaryExpr(base.Pos, ir.OLT, l, ir.NewInt(0)), nil, nil)
 			niflen.Body = []ir.Node{mkcall("panicmakeslicelen", nil, init)}
 			nif.Body.Append(niflen, mkcall("panicmakeslicecap", nil, init))
-			init.Append(typecheck(nif, ctxStmt))
+			init.Append(typecheck.Stmt(nif))
 
 			t = types.NewArray(t.Elem(), i) // [r]T
-			var_ := temp(t)
+			var_ := typecheck.Temp(t)
 			appendWalkStmt(init, ir.NewAssignStmt(base.Pos, var_, nil)) // zero temp
 			r := ir.NewSliceExpr(base.Pos, ir.OSLICE, var_)             // arr[:l]
 			r.SetSliceBounds(nil, l, nil)
 			// The conv is necessary in case n.Type is named.
-			return walkexpr(typecheck(conv(r, n.Type()), ctxExpr), init)
+			return walkexpr(typecheck.Expr(typecheck.Conv(r, n.Type())), init)
 		}
 
 		// n escapes; set up a call to makeslice.
@@ -1507,11 +1508,11 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		m := ir.NewSliceHeaderExpr(base.Pos, nil, nil, nil, nil)
 		m.SetType(t)
 
-		fn := syslook(fnname)
-		m.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, typename(t.Elem()), conv(len, argtype), conv(cap, argtype))
+		fn := typecheck.LookupRuntime(fnname)
+		m.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, typename(t.Elem()), typecheck.Conv(len, argtype), typecheck.Conv(cap, argtype))
 		m.Ptr.MarkNonNil()
-		m.LenCap = []ir.Node{conv(len, types.Types[types.TINT]), conv(cap, types.Types[types.TINT])}
-		return walkexpr(typecheck(m, ctxExpr), init)
+		m.LenCap = []ir.Node{typecheck.Conv(len, types.Types[types.TINT]), typecheck.Conv(cap, types.Types[types.TINT])}
+		return walkexpr(typecheck.Expr(m), init)
 
 	case ir.OMAKESLICECOPY:
 		n := n.(*ir.MakeExpr)
@@ -1524,7 +1525,7 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			base.Errorf("%v can't be allocated in Go; it is incomplete (or unallocatable)", t.Elem())
 		}
 
-		length := conv(n.Len, types.Types[types.TINT])
+		length := typecheck.Conv(n.Len, types.Types[types.TINT])
 		copylen := ir.NewUnaryExpr(base.Pos, ir.OLEN, n.Cap)
 		copyptr := ir.NewUnaryExpr(base.Pos, ir.OSPTR, n.Cap)
 
@@ -1535,56 +1536,56 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			// We do not check for overflow of len(to)*elem.Width here
 			// since len(from) is an existing checked slice capacity
 			// with same elem.Width for the from slice.
-			size := ir.NewBinaryExpr(base.Pos, ir.OMUL, conv(length, types.Types[types.TUINTPTR]), conv(ir.NewInt(t.Elem().Width), types.Types[types.TUINTPTR]))
+			size := ir.NewBinaryExpr(base.Pos, ir.OMUL, typecheck.Conv(length, types.Types[types.TUINTPTR]), typecheck.Conv(ir.NewInt(t.Elem().Width), types.Types[types.TUINTPTR]))
 
 			// instantiate mallocgc(size uintptr, typ *byte, needszero bool) unsafe.Pointer
-			fn := syslook("mallocgc")
+			fn := typecheck.LookupRuntime("mallocgc")
 			sh := ir.NewSliceHeaderExpr(base.Pos, nil, nil, nil, nil)
-			sh.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, size, nodnil(), ir.NewBool(false))
+			sh.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, size, typecheck.NodNil(), ir.NewBool(false))
 			sh.Ptr.MarkNonNil()
 			sh.LenCap = []ir.Node{length, length}
 			sh.SetType(t)
 
-			s := temp(t)
-			r := typecheck(ir.NewAssignStmt(base.Pos, s, sh), ctxStmt)
+			s := typecheck.Temp(t)
+			r := typecheck.Stmt(ir.NewAssignStmt(base.Pos, s, sh))
 			r = walkexpr(r, init)
 			init.Append(r)
 
 			// instantiate memmove(to *any, frm *any, size uintptr)
-			fn = syslook("memmove")
-			fn = substArgTypes(fn, t.Elem(), t.Elem())
+			fn = typecheck.LookupRuntime("memmove")
+			fn = typecheck.SubstArgTypes(fn, t.Elem(), t.Elem())
 			ncopy := mkcall1(fn, nil, init, ir.NewUnaryExpr(base.Pos, ir.OSPTR, s), copyptr, size)
-			init.Append(walkexpr(typecheck(ncopy, ctxStmt), init))
+			init.Append(walkexpr(typecheck.Stmt(ncopy), init))
 
 			return s
 		}
 		// Replace make+copy with runtime.makeslicecopy.
 		// instantiate makeslicecopy(typ *byte, tolen int, fromlen int, from unsafe.Pointer) unsafe.Pointer
-		fn := syslook("makeslicecopy")
+		fn := typecheck.LookupRuntime("makeslicecopy")
 		s := ir.NewSliceHeaderExpr(base.Pos, nil, nil, nil, nil)
-		s.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, typename(t.Elem()), length, copylen, conv(copyptr, types.Types[types.TUNSAFEPTR]))
+		s.Ptr = mkcall1(fn, types.Types[types.TUNSAFEPTR], init, typename(t.Elem()), length, copylen, typecheck.Conv(copyptr, types.Types[types.TUNSAFEPTR]))
 		s.Ptr.MarkNonNil()
 		s.LenCap = []ir.Node{length, length}
 		s.SetType(t)
-		return walkexpr(typecheck(s, ctxExpr), init)
+		return walkexpr(typecheck.Expr(s), init)
 
 	case ir.ORUNESTR:
 		n := n.(*ir.ConvExpr)
-		a := nodnil()
+		a := typecheck.NodNil()
 		if n.Esc() == ir.EscNone {
 			t := types.NewArray(types.Types[types.TUINT8], 4)
-			a = nodAddr(temp(t))
+			a = typecheck.NodAddr(typecheck.Temp(t))
 		}
 		// intstring(*[4]byte, rune)
-		return mkcall("intstring", n.Type(), init, a, conv(n.X, types.Types[types.TINT64]))
+		return mkcall("intstring", n.Type(), init, a, typecheck.Conv(n.X, types.Types[types.TINT64]))
 
 	case ir.OBYTES2STR, ir.ORUNES2STR:
 		n := n.(*ir.ConvExpr)
-		a := nodnil()
+		a := typecheck.NodNil()
 		if n.Esc() == ir.EscNone {
 			// Create temporary buffer for string on stack.
 			t := types.NewArray(types.Types[types.TUINT8], tmpstringbufsize)
-			a = nodAddr(temp(t))
+			a = typecheck.NodAddr(typecheck.Temp(t))
 		}
 		if n.Op() == ir.ORUNES2STR {
 			// slicerunetostring(*[32]byte, []rune) string
@@ -1618,16 +1619,16 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			t := types.NewArray(types.Types[types.TUINT8], int64(len(sc)))
 			var a ir.Node
 			if n.Esc() == ir.EscNone && len(sc) <= int(ir.MaxImplicitStackVarSize) {
-				a = nodAddr(temp(t))
+				a = typecheck.NodAddr(typecheck.Temp(t))
 			} else {
 				a = callnew(t)
 			}
-			p := temp(t.PtrTo()) // *[n]byte
-			init.Append(typecheck(ir.NewAssignStmt(base.Pos, p, a), ctxStmt))
+			p := typecheck.Temp(t.PtrTo()) // *[n]byte
+			init.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, p, a)))
 
 			// Copy from the static string data to the [n]byte.
 			if len(sc) > 0 {
-				as := ir.NewAssignStmt(base.Pos, ir.NewStarExpr(base.Pos, p), ir.NewStarExpr(base.Pos, convnop(ir.NewUnaryExpr(base.Pos, ir.OSPTR, s), t.PtrTo())))
+				as := ir.NewAssignStmt(base.Pos, ir.NewStarExpr(base.Pos, p), ir.NewStarExpr(base.Pos, typecheck.ConvNop(ir.NewUnaryExpr(base.Pos, ir.OSPTR, s), t.PtrTo())))
 				appendWalkStmt(init, as)
 			}
 
@@ -1638,14 +1639,14 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			return walkexpr(slice, init)
 		}
 
-		a := nodnil()
+		a := typecheck.NodNil()
 		if n.Esc() == ir.EscNone {
 			// Create temporary buffer for slice on stack.
 			t := types.NewArray(types.Types[types.TUINT8], tmpstringbufsize)
-			a = nodAddr(temp(t))
+			a = typecheck.NodAddr(typecheck.Temp(t))
 		}
 		// stringtoslicebyte(*32[byte], string) []byte
-		return mkcall("stringtoslicebyte", n.Type(), init, a, conv(s, types.Types[types.TSTRING]))
+		return mkcall("stringtoslicebyte", n.Type(), init, a, typecheck.Conv(s, types.Types[types.TSTRING]))
 
 	case ir.OSTR2BYTESTMP:
 		// []byte(string) conversion that creates a slice
@@ -1661,14 +1662,14 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 
 	case ir.OSTR2RUNES:
 		n := n.(*ir.ConvExpr)
-		a := nodnil()
+		a := typecheck.NodNil()
 		if n.Esc() == ir.EscNone {
 			// Create temporary buffer for slice on stack.
 			t := types.NewArray(types.Types[types.TINT32], tmpstringbufsize)
-			a = nodAddr(temp(t))
+			a = typecheck.NodAddr(typecheck.Temp(t))
 		}
 		// stringtoslicerune(*[32]rune, string) []rune
-		return mkcall("stringtoslicerune", n.Type(), init, a, conv(n.X, types.Types[types.TSTRING]))
+		return mkcall("stringtoslicerune", n.Type(), init, a, typecheck.Conv(n.X, types.Types[types.TSTRING]))
 
 	case ir.OARRAYLIT, ir.OSLICELIT, ir.OMAPLIT, ir.OSTRUCTLIT, ir.OPTRLIT:
 		if isStaticCompositeLiteral(n) && !canSSAType(n.Type()) {
@@ -1677,18 +1678,18 @@ func walkexpr1(n ir.Node, init *ir.Nodes) ir.Node {
 			// Make direct reference to the static data. See issue 12841.
 			vstat := readonlystaticname(n.Type())
 			fixedlit(inInitFunction, initKindStatic, n, vstat, init)
-			return typecheck(vstat, ctxExpr)
+			return typecheck.Expr(vstat)
 		}
-		var_ := temp(n.Type())
+		var_ := typecheck.Temp(n.Type())
 		anylit(n, var_, init)
 		return var_
 
 	case ir.OSEND:
 		n := n.(*ir.SendStmt)
 		n1 := n.Value
-		n1 = assignconv(n1, n.Chan.Type().Elem(), "chan send")
+		n1 = typecheck.AssignConv(n1, n.Chan.Type().Elem(), "chan send")
 		n1 = walkexpr(n1, init)
-		n1 = nodAddr(n1)
+		n1 = typecheck.NodAddr(n1)
 		return mkcall1(chanfn("chansend1", 2, n.Chan.Type()), nil, init, n.Chan, n1)
 
 	case ir.OCLOSURE:
@@ -1871,8 +1872,8 @@ func ascompatet(nl ir.Nodes, nr *types.Type) []ir.Node {
 		// Any assignment to an lvalue that might cause a function call must be
 		// deferred until all the returned values have been read.
 		if fncall(l, r.Type) {
-			tmp := ir.Node(temp(r.Type))
-			tmp = typecheck(tmp, ctxExpr)
+			tmp := ir.Node(typecheck.Temp(r.Type))
+			tmp = typecheck.Expr(tmp)
 			a := convas(ir.NewAssignStmt(base.Pos, l, tmp), &mm)
 			mm.Append(a)
 			l = tmp
@@ -1895,48 +1896,6 @@ func ascompatet(nl ir.Nodes, nr *types.Type) []ir.Node {
 	return append(nn, mm...)
 }
 
-// package all the arguments that match a ... T parameter into a []T.
-func mkdotargslice(typ *types.Type, args []ir.Node) ir.Node {
-	var n ir.Node
-	if len(args) == 0 {
-		n = nodnil()
-		n.SetType(typ)
-	} else {
-		lit := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(typ).(ir.Ntype), nil)
-		lit.List.Append(args...)
-		lit.SetImplicit(true)
-		n = lit
-	}
-
-	n = typecheck(n, ctxExpr)
-	if n.Type() == nil {
-		base.Fatalf("mkdotargslice: typecheck failed")
-	}
-	return n
-}
-
-// fixVariadicCall rewrites calls to variadic functions to use an
-// explicit ... argument if one is not already present.
-func fixVariadicCall(call *ir.CallExpr) {
-	fntype := call.X.Type()
-	if !fntype.IsVariadic() || call.IsDDD {
-		return
-	}
-
-	vi := fntype.NumParams() - 1
-	vt := fntype.Params().Field(vi).Type
-
-	args := call.Args
-	extra := args[vi:]
-	slice := mkdotargslice(vt, extra)
-	for i := range extra {
-		extra[i] = nil // allow GC
-	}
-
-	call.Args.Set(append(args[:vi], slice))
-	call.IsDDD = true
-}
-
 func walkCall(n *ir.CallExpr, init *ir.Nodes) {
 	if len(n.Rargs) != 0 {
 		return // already walked
@@ -1978,7 +1937,7 @@ func walkCall(n *ir.CallExpr, init *ir.Nodes) {
 		}
 		if base.Flag.Cfg.Instrumenting || fncall(arg, t) {
 			// make assignment of fncall to tempAt
-			tmp := temp(t)
+			tmp := typecheck.Temp(t)
 			a := convas(ir.NewAssignStmt(base.Pos, tmp, arg), init)
 			tempAssigns = append(tempAssigns, a)
 			// replace arg with temp
@@ -2032,22 +1991,22 @@ func walkprint(nn *ir.CallExpr, init *ir.Nodes) ir.Node {
 	for i, n := range nn.Args {
 		if n.Op() == ir.OLITERAL {
 			if n.Type() == types.UntypedRune {
-				n = defaultlit(n, types.RuneType)
+				n = typecheck.DefaultLit(n, types.RuneType)
 			}
 
 			switch n.Val().Kind() {
 			case constant.Int:
-				n = defaultlit(n, types.Types[types.TINT64])
+				n = typecheck.DefaultLit(n, types.Types[types.TINT64])
 
 			case constant.Float:
-				n = defaultlit(n, types.Types[types.TFLOAT64])
+				n = typecheck.DefaultLit(n, types.Types[types.TFLOAT64])
 			}
 		}
 
 		if n.Op() != ir.OLITERAL && n.Type() != nil && n.Type().Kind() == types.TIDEAL {
-			n = defaultlit(n, types.Types[types.TINT64])
+			n = typecheck.DefaultLit(n, types.Types[types.TINT64])
 		}
-		n = defaultlit(n, nil)
+		n = typecheck.DefaultLit(n, nil)
 		nn.Args[i] = n
 		if n.Type() == nil || n.Type().Kind() == types.TFORW {
 			continue
@@ -2057,14 +2016,14 @@ func walkprint(nn *ir.CallExpr, init *ir.Nodes) ir.Node {
 		switch n.Type().Kind() {
 		case types.TINTER:
 			if n.Type().IsEmptyInterface() {
-				on = syslook("printeface")
+				on = typecheck.LookupRuntime("printeface")
 			} else {
-				on = syslook("printiface")
+				on = typecheck.LookupRuntime("printiface")
 			}
-			on = substArgTypes(on, n.Type()) // any-1
+			on = typecheck.SubstArgTypes(on, n.Type()) // any-1
 		case types.TPTR:
 			if n.Type().Elem().NotInHeap() {
-				on = syslook("printuintptr")
+				on = typecheck.LookupRuntime("printuintptr")
 				n = ir.NewConvExpr(base.Pos, ir.OCONV, nil, n)
 				n.SetType(types.Types[types.TUNSAFEPTR])
 				n = ir.NewConvExpr(base.Pos, ir.OCONV, nil, n)
@@ -2073,25 +2032,25 @@ func walkprint(nn *ir.CallExpr, init *ir.Nodes) ir.Node {
 			}
 			fallthrough
 		case types.TCHAN, types.TMAP, types.TFUNC, types.TUNSAFEPTR:
-			on = syslook("printpointer")
-			on = substArgTypes(on, n.Type()) // any-1
+			on = typecheck.LookupRuntime("printpointer")
+			on = typecheck.SubstArgTypes(on, n.Type()) // any-1
 		case types.TSLICE:
-			on = syslook("printslice")
-			on = substArgTypes(on, n.Type()) // any-1
+			on = typecheck.LookupRuntime("printslice")
+			on = typecheck.SubstArgTypes(on, n.Type()) // any-1
 		case types.TUINT, types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64, types.TUINTPTR:
 			if types.IsRuntimePkg(n.Type().Sym().Pkg) && n.Type().Sym().Name == "hex" {
-				on = syslook("printhex")
+				on = typecheck.LookupRuntime("printhex")
 			} else {
-				on = syslook("printuint")
+				on = typecheck.LookupRuntime("printuint")
 			}
 		case types.TINT, types.TINT8, types.TINT16, types.TINT32, types.TINT64:
-			on = syslook("printint")
+			on = typecheck.LookupRuntime("printint")
 		case types.TFLOAT32, types.TFLOAT64:
-			on = syslook("printfloat")
+			on = typecheck.LookupRuntime("printfloat")
 		case types.TCOMPLEX64, types.TCOMPLEX128:
-			on = syslook("printcomplex")
+			on = typecheck.LookupRuntime("printcomplex")
 		case types.TBOOL:
-			on = syslook("printbool")
+			on = typecheck.LookupRuntime("printbool")
 		case types.TSTRING:
 			cs := ""
 			if ir.IsConst(n, constant.String) {
@@ -2099,11 +2058,11 @@ func walkprint(nn *ir.CallExpr, init *ir.Nodes) ir.Node {
 			}
 			switch cs {
 			case " ":
-				on = syslook("printsp")
+				on = typecheck.LookupRuntime("printsp")
 			case "\n":
-				on = syslook("printnl")
+				on = typecheck.LookupRuntime("printnl")
 			default:
-				on = syslook("printstring")
+				on = typecheck.LookupRuntime("printstring")
 			}
 		default:
 			badtype(ir.OPRINT, n.Type(), nil)
@@ -2124,12 +2083,12 @@ func walkprint(nn *ir.CallExpr, init *ir.Nodes) ir.Node {
 
 	calls = append(calls, mkcall("printunlock", nil, init))
 
-	typecheckslice(calls, ctxStmt)
+	typecheck.Stmts(calls)
 	walkexprlist(calls, init)
 
 	r := ir.NewBlockStmt(base.Pos, nil)
 	r.List.Set(calls)
-	return walkstmt(typecheck(r, ctxStmt))
+	return walkstmt(typecheck.Stmt(r))
 }
 
 func callnew(t *types.Type) ir.Node {
@@ -2160,12 +2119,12 @@ func convas(n *ir.AssignStmt, init *ir.Nodes) *ir.AssignStmt {
 	}
 
 	if ir.IsBlank(n.X) {
-		n.Y = defaultlit(n.Y, nil)
+		n.Y = typecheck.DefaultLit(n.Y, nil)
 		return n
 	}
 
 	if !types.Identical(lt, rt) {
-		n.Y = assignconv(n.Y, lt, "assignment")
+		n.Y = typecheck.AssignConv(n.Y, lt, "assignment")
 		n.Y = walkexpr(n.Y, init)
 	}
 	types.CalcSize(n.Y.Type())
@@ -2258,8 +2217,8 @@ func reorder3save(n ir.Node, all []*ir.AssignStmt, i int, early *[]ir.Node) ir.N
 		return n
 	}
 
-	q := ir.Node(temp(n.Type()))
-	as := typecheck(ir.NewAssignStmt(base.Pos, q, n), ctxStmt)
+	q := ir.Node(typecheck.Temp(n.Type()))
+	as := typecheck.Stmt(ir.NewAssignStmt(base.Pos, q, n))
 	*early = append(*early, as)
 	return q
 }
@@ -2455,7 +2414,7 @@ func paramstoheap(params *types.Type) []ir.Node {
 		if stackcopy := v.Name().Stackcopy; stackcopy != nil {
 			nn = append(nn, walkstmt(ir.NewDecl(base.Pos, ir.ODCL, v)))
 			if stackcopy.Class_ == ir.PPARAM {
-				nn = append(nn, walkstmt(typecheck(ir.NewAssignStmt(base.Pos, v, stackcopy), ctxStmt)))
+				nn = append(nn, walkstmt(typecheck.Stmt(ir.NewAssignStmt(base.Pos, v, stackcopy))))
 			}
 		}
 	}
@@ -2503,7 +2462,7 @@ func returnsfromheap(params *types.Type) []ir.Node {
 			continue
 		}
 		if stackcopy := v.Name().Stackcopy; stackcopy != nil && stackcopy.Class_ == ir.PPARAMOUT {
-			nn = append(nn, walkstmt(typecheck(ir.NewAssignStmt(base.Pos, stackcopy, v), ctxStmt)))
+			nn = append(nn, walkstmt(typecheck.Stmt(ir.NewAssignStmt(base.Pos, stackcopy, v))))
 		}
 	}
 
@@ -2536,41 +2495,19 @@ func vmkcall(fn ir.Node, t *types.Type, init *ir.Nodes, va []ir.Node) *ir.CallEx
 	}
 
 	call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, va)
-	TypecheckCall(call)
+	typecheck.Call(call)
 	call.SetType(t)
 	return walkexpr(call, init).(*ir.CallExpr)
 }
 
 func mkcall(name string, t *types.Type, init *ir.Nodes, args ...ir.Node) *ir.CallExpr {
-	return vmkcall(syslook(name), t, init, args)
+	return vmkcall(typecheck.LookupRuntime(name), t, init, args)
 }
 
 func mkcall1(fn ir.Node, t *types.Type, init *ir.Nodes, args ...ir.Node) *ir.CallExpr {
 	return vmkcall(fn, t, init, args)
 }
 
-func conv(n ir.Node, t *types.Type) ir.Node {
-	if types.Identical(n.Type(), t) {
-		return n
-	}
-	n = ir.NewConvExpr(base.Pos, ir.OCONV, nil, n)
-	n.SetType(t)
-	n = typecheck(n, ctxExpr)
-	return n
-}
-
-// convnop converts node n to type t using the OCONVNOP op
-// and typechecks the result with ctxExpr.
-func convnop(n ir.Node, t *types.Type) ir.Node {
-	if types.Identical(n.Type(), t) {
-		return n
-	}
-	n = ir.NewConvExpr(base.Pos, ir.OCONVNOP, nil, n)
-	n.SetType(t)
-	n = typecheck(n, ctxExpr)
-	return n
-}
-
 // byteindex converts n, which is byte-sized, to an int used to index into an array.
 // We cannot use conv, because we allow converting bool to int here,
 // which is forbidden in user code.
@@ -2594,14 +2531,14 @@ func chanfn(name string, n int, t *types.Type) ir.Node {
 	if !t.IsChan() {
 		base.Fatalf("chanfn %v", t)
 	}
-	fn := syslook(name)
+	fn := typecheck.LookupRuntime(name)
 	switch n {
 	default:
 		base.Fatalf("chanfn %d", n)
 	case 1:
-		fn = substArgTypes(fn, t.Elem())
+		fn = typecheck.SubstArgTypes(fn, t.Elem())
 	case 2:
-		fn = substArgTypes(fn, t.Elem(), t.Elem())
+		fn = typecheck.SubstArgTypes(fn, t.Elem(), t.Elem())
 	}
 	return fn
 }
@@ -2610,8 +2547,8 @@ func mapfn(name string, t *types.Type) ir.Node {
 	if !t.IsMap() {
 		base.Fatalf("mapfn %v", t)
 	}
-	fn := syslook(name)
-	fn = substArgTypes(fn, t.Key(), t.Elem(), t.Key(), t.Elem())
+	fn := typecheck.LookupRuntime(name)
+	fn = typecheck.SubstArgTypes(fn, t.Key(), t.Elem(), t.Key(), t.Elem())
 	return fn
 }
 
@@ -2619,8 +2556,8 @@ func mapfndel(name string, t *types.Type) ir.Node {
 	if !t.IsMap() {
 		base.Fatalf("mapfn %v", t)
 	}
-	fn := syslook(name)
-	fn = substArgTypes(fn, t.Key(), t.Elem(), t.Key())
+	fn := typecheck.LookupRuntime(name)
+	fn = typecheck.SubstArgTypes(fn, t.Key(), t.Elem(), t.Key())
 	return fn
 }
 
@@ -2675,8 +2612,8 @@ func mapfast(t *types.Type) int {
 }
 
 func writebarrierfn(name string, l *types.Type, r *types.Type) ir.Node {
-	fn := syslook(name)
-	fn = substArgTypes(fn, l, r)
+	fn := typecheck.LookupRuntime(name)
+	fn = typecheck.SubstArgTypes(fn, l, r)
 	return fn
 }
 
@@ -2687,7 +2624,7 @@ func addstr(n *ir.AddStringExpr, init *ir.Nodes) ir.Node {
 		base.Fatalf("addstr count %d too small", c)
 	}
 
-	buf := nodnil()
+	buf := typecheck.NodNil()
 	if n.Esc() == ir.EscNone {
 		sz := int64(0)
 		for _, n1 := range n.List {
@@ -2700,14 +2637,14 @@ func addstr(n *ir.AddStringExpr, init *ir.Nodes) ir.Node {
 		if sz < tmpstringbufsize {
 			// Create temporary buffer for result string on stack.
 			t := types.NewArray(types.Types[types.TUINT8], tmpstringbufsize)
-			buf = nodAddr(temp(t))
+			buf = typecheck.NodAddr(typecheck.Temp(t))
 		}
 	}
 
 	// build list of string arguments
 	args := []ir.Node{buf}
 	for _, n2 := range n.List {
-		args = append(args, conv(n2, types.Types[types.TSTRING]))
+		args = append(args, typecheck.Conv(n2, types.Types[types.TSTRING]))
 	}
 
 	var fn string
@@ -2727,10 +2664,10 @@ func addstr(n *ir.AddStringExpr, init *ir.Nodes) ir.Node {
 		slice.SetEsc(ir.EscNone)
 	}
 
-	cat := syslook(fn)
+	cat := typecheck.LookupRuntime(fn)
 	r := ir.NewCallExpr(base.Pos, ir.OCALL, cat, nil)
 	r.Args.Set(args)
-	r1 := typecheck(r, ctxExpr)
+	r1 := typecheck.Expr(r)
 	r1 = walkexpr(r1, init)
 	r1.SetType(n.Type())
 
@@ -2774,24 +2711,24 @@ func appendslice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	var nodes ir.Nodes
 
 	// var s []T
-	s := temp(l1.Type())
+	s := typecheck.Temp(l1.Type())
 	nodes.Append(ir.NewAssignStmt(base.Pos, s, l1)) // s = l1
 
 	elemtype := s.Type().Elem()
 
 	// n := len(s) + len(l2)
-	nn := temp(types.Types[types.TINT])
+	nn := typecheck.Temp(types.Types[types.TINT])
 	nodes.Append(ir.NewAssignStmt(base.Pos, nn, ir.NewBinaryExpr(base.Pos, ir.OADD, ir.NewUnaryExpr(base.Pos, ir.OLEN, s), ir.NewUnaryExpr(base.Pos, ir.OLEN, l2))))
 
 	// if uint(n) > uint(cap(s))
 	nif := ir.NewIfStmt(base.Pos, nil, nil, nil)
-	nuint := conv(nn, types.Types[types.TUINT])
-	scapuint := conv(ir.NewUnaryExpr(base.Pos, ir.OCAP, s), types.Types[types.TUINT])
+	nuint := typecheck.Conv(nn, types.Types[types.TUINT])
+	scapuint := typecheck.Conv(ir.NewUnaryExpr(base.Pos, ir.OCAP, s), types.Types[types.TUINT])
 	nif.Cond = ir.NewBinaryExpr(base.Pos, ir.OGT, nuint, scapuint)
 
 	// instantiate growslice(typ *type, []any, int) []any
-	fn := syslook("growslice")
-	fn = substArgTypes(fn, elemtype, elemtype)
+	fn := typecheck.LookupRuntime("growslice")
+	fn = typecheck.SubstArgTypes(fn, elemtype, elemtype)
 
 	// s = growslice(T, s, n)
 	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, s, mkcall1(fn, s.Type(), nif.PtrInit(), typename(elemtype), s, nn))}
@@ -2813,8 +2750,8 @@ func appendslice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 		ir.CurFunc.SetWBPos(n.Pos())
 
 		// instantiate typedslicecopy(typ *type, dstPtr *any, dstLen int, srcPtr *any, srcLen int) int
-		fn := syslook("typedslicecopy")
-		fn = substArgTypes(fn, l1.Type().Elem(), l2.Type().Elem())
+		fn := typecheck.LookupRuntime("typedslicecopy")
+		fn = typecheck.SubstArgTypes(fn, l1.Type().Elem(), l2.Type().Elem())
 		ptr1, len1 := backingArrayPtrLen(cheapexpr(slice, &nodes))
 		ptr2, len2 := backingArrayPtrLen(l2)
 		ncopy = mkcall1(fn, types.Types[types.TINT], &nodes, typename(elemtype), ptr1, len1, ptr2, len2)
@@ -2829,28 +2766,28 @@ func appendslice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 		ptr1, len1 := backingArrayPtrLen(cheapexpr(slice, &nodes))
 		ptr2, len2 := backingArrayPtrLen(l2)
 
-		fn := syslook("slicecopy")
-		fn = substArgTypes(fn, ptr1.Type().Elem(), ptr2.Type().Elem())
+		fn := typecheck.LookupRuntime("slicecopy")
+		fn = typecheck.SubstArgTypes(fn, ptr1.Type().Elem(), ptr2.Type().Elem())
 		ncopy = mkcall1(fn, types.Types[types.TINT], &nodes, ptr1, len1, ptr2, len2, ir.NewInt(elemtype.Width))
 	} else {
 		// memmove(&s[len(l1)], &l2[0], len(l2)*sizeof(T))
 		ix := ir.NewIndexExpr(base.Pos, s, ir.NewUnaryExpr(base.Pos, ir.OLEN, l1))
 		ix.SetBounded(true)
-		addr := nodAddr(ix)
+		addr := typecheck.NodAddr(ix)
 
 		sptr := ir.NewUnaryExpr(base.Pos, ir.OSPTR, l2)
 
-		nwid := cheapexpr(conv(ir.NewUnaryExpr(base.Pos, ir.OLEN, l2), types.Types[types.TUINTPTR]), &nodes)
+		nwid := cheapexpr(typecheck.Conv(ir.NewUnaryExpr(base.Pos, ir.OLEN, l2), types.Types[types.TUINTPTR]), &nodes)
 		nwid = ir.NewBinaryExpr(base.Pos, ir.OMUL, nwid, ir.NewInt(elemtype.Width))
 
 		// instantiate func memmove(to *any, frm *any, length uintptr)
-		fn := syslook("memmove")
-		fn = substArgTypes(fn, elemtype, elemtype)
+		fn := typecheck.LookupRuntime("memmove")
+		fn = typecheck.SubstArgTypes(fn, elemtype, elemtype)
 		ncopy = mkcall1(fn, nil, &nodes, addr, sptr, nwid)
 	}
 	ln := append(nodes, ncopy)
 
-	typecheckslice(ln, ctxStmt)
+	typecheck.Stmts(ln)
 	walkstmtlist(ln)
 	init.Append(ln...)
 	return s
@@ -2925,8 +2862,8 @@ func extendslice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	// isAppendOfMake made sure all possible positive values of l2 fit into an uint.
 	// The case of l2 overflow when converting from e.g. uint to int is handled by an explicit
 	// check of l2 < 0 at runtime which is generated below.
-	l2 := conv(n.Args[1].(*ir.MakeExpr).Len, types.Types[types.TINT])
-	l2 = typecheck(l2, ctxExpr)
+	l2 := typecheck.Conv(n.Args[1].(*ir.MakeExpr).Len, types.Types[types.TINT])
+	l2 = typecheck.Expr(l2)
 	n.Args[1] = l2 // walkAppendArgs expects l2 in n.List.Second().
 
 	walkAppendArgs(n, init)
@@ -2945,23 +2882,23 @@ func extendslice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	nodes = append(nodes, nifneg)
 
 	// s := l1
-	s := temp(l1.Type())
+	s := typecheck.Temp(l1.Type())
 	nodes = append(nodes, ir.NewAssignStmt(base.Pos, s, l1))
 
 	elemtype := s.Type().Elem()
 
 	// n := len(s) + l2
-	nn := temp(types.Types[types.TINT])
+	nn := typecheck.Temp(types.Types[types.TINT])
 	nodes = append(nodes, ir.NewAssignStmt(base.Pos, nn, ir.NewBinaryExpr(base.Pos, ir.OADD, ir.NewUnaryExpr(base.Pos, ir.OLEN, s), l2)))
 
 	// if uint(n) > uint(cap(s))
-	nuint := conv(nn, types.Types[types.TUINT])
-	capuint := conv(ir.NewUnaryExpr(base.Pos, ir.OCAP, s), types.Types[types.TUINT])
+	nuint := typecheck.Conv(nn, types.Types[types.TUINT])
+	capuint := typecheck.Conv(ir.NewUnaryExpr(base.Pos, ir.OCAP, s), types.Types[types.TUINT])
 	nif := ir.NewIfStmt(base.Pos, ir.NewBinaryExpr(base.Pos, ir.OGT, nuint, capuint), nil, nil)
 
 	// instantiate growslice(typ *type, old []any, newcap int) []any
-	fn := syslook("growslice")
-	fn = substArgTypes(fn, elemtype, elemtype)
+	fn := typecheck.LookupRuntime("growslice")
+	fn = typecheck.SubstArgTypes(fn, elemtype, elemtype)
 
 	// s = growslice(T, s, n)
 	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, s, mkcall1(fn, s.Type(), nif.PtrInit(), typename(elemtype), s, nn))}
@@ -2974,22 +2911,22 @@ func extendslice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	nodes = append(nodes, ir.NewAssignStmt(base.Pos, s, nt))
 
 	// lptr := &l1[0]
-	l1ptr := temp(l1.Type().Elem().PtrTo())
+	l1ptr := typecheck.Temp(l1.Type().Elem().PtrTo())
 	tmp := ir.NewUnaryExpr(base.Pos, ir.OSPTR, l1)
 	nodes = append(nodes, ir.NewAssignStmt(base.Pos, l1ptr, tmp))
 
 	// sptr := &s[0]
-	sptr := temp(elemtype.PtrTo())
+	sptr := typecheck.Temp(elemtype.PtrTo())
 	tmp = ir.NewUnaryExpr(base.Pos, ir.OSPTR, s)
 	nodes = append(nodes, ir.NewAssignStmt(base.Pos, sptr, tmp))
 
 	// hp := &s[len(l1)]
 	ix := ir.NewIndexExpr(base.Pos, s, ir.NewUnaryExpr(base.Pos, ir.OLEN, l1))
 	ix.SetBounded(true)
-	hp := convnop(nodAddr(ix), types.Types[types.TUNSAFEPTR])
+	hp := typecheck.ConvNop(typecheck.NodAddr(ix), types.Types[types.TUNSAFEPTR])
 
 	// hn := l2 * sizeof(elem(s))
-	hn := conv(ir.NewBinaryExpr(base.Pos, ir.OMUL, l2, ir.NewInt(elemtype.Width)), types.Types[types.TUINTPTR])
+	hn := typecheck.Conv(ir.NewBinaryExpr(base.Pos, ir.OMUL, l2, ir.NewInt(elemtype.Width)), types.Types[types.TUINTPTR])
 
 	clrname := "memclrNoHeapPointers"
 	hasPointers := elemtype.HasPointers()
@@ -3011,7 +2948,7 @@ func extendslice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 		nodes = append(nodes, clr...)
 	}
 
-	typecheckslice(nodes, ctxStmt)
+	typecheck.Stmts(nodes)
 	walkstmtlist(nodes)
 	init.Append(nodes...)
 	return s
@@ -3057,7 +2994,7 @@ func walkappend(n *ir.CallExpr, init *ir.Nodes, dst ir.Node) ir.Node {
 	for i, n := range ls {
 		n = cheapexpr(n, init)
 		if !types.Identical(n.Type(), nsrc.Type().Elem()) {
-			n = assignconv(n, nsrc.Type().Elem(), "append")
+			n = typecheck.AssignConv(n, nsrc.Type().Elem(), "append")
 			n = walkexpr(n, init)
 		}
 		ls[i] = n
@@ -3076,22 +3013,22 @@ func walkappend(n *ir.CallExpr, init *ir.Nodes, dst ir.Node) ir.Node {
 
 	var l []ir.Node
 
-	ns := temp(nsrc.Type())
+	ns := typecheck.Temp(nsrc.Type())
 	l = append(l, ir.NewAssignStmt(base.Pos, ns, nsrc)) // s = src
 
 	na := ir.NewInt(int64(argc))                 // const argc
 	nif := ir.NewIfStmt(base.Pos, nil, nil, nil) // if cap(s) - len(s) < argc
 	nif.Cond = ir.NewBinaryExpr(base.Pos, ir.OLT, ir.NewBinaryExpr(base.Pos, ir.OSUB, ir.NewUnaryExpr(base.Pos, ir.OCAP, ns), ir.NewUnaryExpr(base.Pos, ir.OLEN, ns)), na)
 
-	fn := syslook("growslice") //   growslice(<type>, old []T, mincap int) (ret []T)
-	fn = substArgTypes(fn, ns.Type().Elem(), ns.Type().Elem())
+	fn := typecheck.LookupRuntime("growslice") //   growslice(<type>, old []T, mincap int) (ret []T)
+	fn = typecheck.SubstArgTypes(fn, ns.Type().Elem(), ns.Type().Elem())
 
 	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, ns, mkcall1(fn, ns.Type(), nif.PtrInit(), typename(ns.Type().Elem()), ns,
 		ir.NewBinaryExpr(base.Pos, ir.OADD, ir.NewUnaryExpr(base.Pos, ir.OLEN, ns), na)))}
 
 	l = append(l, nif)
 
-	nn := temp(types.Types[types.TINT])
+	nn := typecheck.Temp(types.Types[types.TINT])
 	l = append(l, ir.NewAssignStmt(base.Pos, nn, ir.NewUnaryExpr(base.Pos, ir.OLEN, ns))) // n = len(s)
 
 	slice := ir.NewSliceExpr(base.Pos, ir.OSLICE, ns) // ...s[:n+argc]
@@ -3109,7 +3046,7 @@ func walkappend(n *ir.CallExpr, init *ir.Nodes, dst ir.Node) ir.Node {
 		}
 	}
 
-	typecheckslice(l, ctxStmt)
+	typecheck.Stmts(l)
 	walkstmtlist(l)
 	init.Append(l...)
 	return ns
@@ -3147,16 +3084,16 @@ func copyany(n *ir.BinaryExpr, init *ir.Nodes, runtimecall bool) ir.Node {
 		n.Y = cheapexpr(n.Y, init)
 		ptrR, lenR := backingArrayPtrLen(n.Y)
 
-		fn := syslook("slicecopy")
-		fn = substArgTypes(fn, ptrL.Type().Elem(), ptrR.Type().Elem())
+		fn := typecheck.LookupRuntime("slicecopy")
+		fn = typecheck.SubstArgTypes(fn, ptrL.Type().Elem(), ptrR.Type().Elem())
 
 		return mkcall1(fn, n.Type(), init, ptrL, lenL, ptrR, lenR, ir.NewInt(n.X.Type().Elem().Width))
 	}
 
 	n.X = walkexpr(n.X, init)
 	n.Y = walkexpr(n.Y, init)
-	nl := temp(n.X.Type())
-	nr := temp(n.Y.Type())
+	nl := typecheck.Temp(n.X.Type())
+	nr := typecheck.Temp(n.Y.Type())
 	var l []ir.Node
 	l = append(l, ir.NewAssignStmt(base.Pos, nl, n.X))
 	l = append(l, ir.NewAssignStmt(base.Pos, nr, n.Y))
@@ -3164,7 +3101,7 @@ func copyany(n *ir.BinaryExpr, init *ir.Nodes, runtimecall bool) ir.Node {
 	nfrm := ir.NewUnaryExpr(base.Pos, ir.OSPTR, nr)
 	nto := ir.NewUnaryExpr(base.Pos, ir.OSPTR, nl)
 
-	nlen := temp(types.Types[types.TINT])
+	nlen := typecheck.Temp(types.Types[types.TINT])
 
 	// n = len(to)
 	l = append(l, ir.NewAssignStmt(base.Pos, nlen, ir.NewUnaryExpr(base.Pos, ir.OLEN, nl)))
@@ -3181,16 +3118,16 @@ func copyany(n *ir.BinaryExpr, init *ir.Nodes, runtimecall bool) ir.Node {
 	ne.Likely = true
 	l = append(l, ne)
 
-	fn := syslook("memmove")
-	fn = substArgTypes(fn, nl.Type().Elem(), nl.Type().Elem())
-	nwid := ir.Node(temp(types.Types[types.TUINTPTR]))
-	setwid := ir.NewAssignStmt(base.Pos, nwid, conv(nlen, types.Types[types.TUINTPTR]))
+	fn := typecheck.LookupRuntime("memmove")
+	fn = typecheck.SubstArgTypes(fn, nl.Type().Elem(), nl.Type().Elem())
+	nwid := ir.Node(typecheck.Temp(types.Types[types.TUINTPTR]))
+	setwid := ir.NewAssignStmt(base.Pos, nwid, typecheck.Conv(nlen, types.Types[types.TUINTPTR]))
 	ne.Body.Append(setwid)
 	nwid = ir.NewBinaryExpr(base.Pos, ir.OMUL, nwid, ir.NewInt(nl.Type().Elem().Width))
 	call := mkcall1(fn, nil, init, nto, nfrm, nwid)
 	ne.Body.Append(call)
 
-	typecheckslice(l, ctxStmt)
+	typecheck.Stmts(l)
 	walkstmtlist(l)
 	init.Append(l...)
 	return nlen
@@ -3203,14 +3140,14 @@ func eqfor(t *types.Type) (n ir.Node, needsize bool) {
 	// is handled by walkcompare.
 	switch a, _ := types.AlgType(t); a {
 	case types.AMEM:
-		n := syslook("memequal")
-		n = substArgTypes(n, t, t)
+		n := typecheck.LookupRuntime("memequal")
+		n = typecheck.SubstArgTypes(n, t, t)
 		return n, true
 	case types.ASPECIAL:
 		sym := typesymprefix(".eq", t)
-		n := NewName(sym)
+		n := typecheck.NewName(sym)
 		ir.MarkFunc(n)
-		n.SetType(functype(nil, []*ir.Field{
+		n.SetType(typecheck.NewFuncType(nil, []*ir.Field{
 			ir.NewField(base.Pos, nil, nil, types.NewPtr(t)),
 			ir.NewField(base.Pos, nil, nil, types.NewPtr(t)),
 		}, []*ir.Field{
@@ -3267,7 +3204,7 @@ func walkcompare(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 			tab.SetTypecheck(1)
 			eqtype = ir.NewBinaryExpr(base.Pos, eq, tab, rtyp)
 		} else {
-			nonnil := ir.NewBinaryExpr(base.Pos, brcom(eq), nodnil(), tab)
+			nonnil := ir.NewBinaryExpr(base.Pos, brcom(eq), typecheck.NodNil(), tab)
 			match := ir.NewBinaryExpr(base.Pos, eq, itabType(tab), rtyp)
 			eqtype = ir.NewLogicalExpr(base.Pos, andor, nonnil, match)
 		}
@@ -3366,8 +3303,8 @@ func walkcompare(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 
 		fn, needsize := eqfor(t)
 		call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
-		call.Args.Append(nodAddr(cmpl))
-		call.Args.Append(nodAddr(cmpr))
+		call.Args.Append(typecheck.NodAddr(cmpl))
+		call.Args.Append(typecheck.NodAddr(cmpr))
 		if needsize {
 			call.Args.Append(ir.NewInt(t.Width))
 		}
@@ -3436,22 +3373,22 @@ func walkcompare(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 			} else {
 				elemType := t.Elem().ToUnsigned()
 				cmplw := ir.Node(ir.NewIndexExpr(base.Pos, cmpl, ir.NewInt(i)))
-				cmplw = conv(cmplw, elemType) // convert to unsigned
-				cmplw = conv(cmplw, convType) // widen
+				cmplw = typecheck.Conv(cmplw, elemType) // convert to unsigned
+				cmplw = typecheck.Conv(cmplw, convType) // widen
 				cmprw := ir.Node(ir.NewIndexExpr(base.Pos, cmpr, ir.NewInt(i)))
-				cmprw = conv(cmprw, elemType)
-				cmprw = conv(cmprw, convType)
+				cmprw = typecheck.Conv(cmprw, elemType)
+				cmprw = typecheck.Conv(cmprw, convType)
 				// For code like this:  uint32(s[0]) | uint32(s[1])<<8 | uint32(s[2])<<16 ...
 				// ssa will generate a single large load.
 				for offset := int64(1); offset < step; offset++ {
 					lb := ir.Node(ir.NewIndexExpr(base.Pos, cmpl, ir.NewInt(i+offset)))
-					lb = conv(lb, elemType)
-					lb = conv(lb, convType)
+					lb = typecheck.Conv(lb, elemType)
+					lb = typecheck.Conv(lb, convType)
 					lb = ir.NewBinaryExpr(base.Pos, ir.OLSH, lb, ir.NewInt(8*t.Elem().Width*offset))
 					cmplw = ir.NewBinaryExpr(base.Pos, ir.OOR, cmplw, lb)
 					rb := ir.Node(ir.NewIndexExpr(base.Pos, cmpr, ir.NewInt(i+offset)))
-					rb = conv(rb, elemType)
-					rb = conv(rb, convType)
+					rb = typecheck.Conv(rb, elemType)
+					rb = typecheck.Conv(rb, convType)
 					rb = ir.NewBinaryExpr(base.Pos, ir.OLSH, rb, ir.NewInt(8*t.Elem().Width*offset))
 					cmprw = ir.NewBinaryExpr(base.Pos, ir.OOR, cmprw, rb)
 				}
@@ -3465,9 +3402,9 @@ func walkcompare(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 		expr = ir.NewBool(n.Op() == ir.OEQ)
 		// We still need to use cmpl and cmpr, in case they contain
 		// an expression which might panic. See issue 23837.
-		t := temp(cmpl.Type())
-		a1 := typecheck(ir.NewAssignStmt(base.Pos, t, cmpl), ctxStmt)
-		a2 := typecheck(ir.NewAssignStmt(base.Pos, t, cmpr), ctxStmt)
+		t := typecheck.Temp(cmpl.Type())
+		a1 := typecheck.Stmt(ir.NewAssignStmt(base.Pos, t, cmpl))
+		a2 := typecheck.Stmt(ir.NewAssignStmt(base.Pos, t, cmpr))
 		init.Append(a1, a2)
 	}
 	return finishcompare(n, expr, init)
@@ -3479,7 +3416,7 @@ func tracecmpArg(n ir.Node, t *types.Type, init *ir.Nodes) ir.Node {
 		n = copyexpr(n, n.Type(), init)
 	}
 
-	return conv(n, t)
+	return typecheck.Conv(n, t)
 }
 
 func walkcompareInterface(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
@@ -3573,13 +3510,13 @@ func walkcompareString(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 					convType = types.Types[types.TUINT16]
 					step = 2
 				}
-				ncsubstr := conv(ir.NewIndexExpr(base.Pos, ncs, ir.NewInt(int64(i))), convType)
+				ncsubstr := typecheck.Conv(ir.NewIndexExpr(base.Pos, ncs, ir.NewInt(int64(i))), convType)
 				csubstr := int64(s[i])
 				// Calculate large constant from bytes as sequence of shifts and ors.
 				// Like this:  uint32(s[0]) | uint32(s[1])<<8 | uint32(s[2])<<16 ...
 				// ssa will combine this into a single large load.
 				for offset := 1; offset < step; offset++ {
-					b := conv(ir.NewIndexExpr(base.Pos, ncs, ir.NewInt(int64(i+offset))), convType)
+					b := typecheck.Conv(ir.NewIndexExpr(base.Pos, ncs, ir.NewInt(int64(i+offset))), convType)
 					b = ir.NewBinaryExpr(base.Pos, ir.OLSH, b, ir.NewInt(int64(8*offset)))
 					ncsubstr = ir.NewBinaryExpr(base.Pos, ir.OOR, ncsubstr, b)
 					csubstr |= int64(s[i+offset]) << uint8(8*offset)
@@ -3612,7 +3549,7 @@ func walkcompareString(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 		}
 	} else {
 		// sys_cmpstring(s1, s2) :: 0
-		r = mkcall("cmpstring", types.Types[types.TINT], init, conv(n.X, types.Types[types.TSTRING]), conv(n.Y, types.Types[types.TSTRING]))
+		r = mkcall("cmpstring", types.Types[types.TINT], init, typecheck.Conv(n.X, types.Types[types.TSTRING]), typecheck.Conv(n.Y, types.Types[types.TSTRING]))
 		r = ir.NewBinaryExpr(base.Pos, n.Op(), r, ir.NewInt(0))
 	}
 
@@ -3622,8 +3559,8 @@ func walkcompareString(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 // The result of finishcompare MUST be assigned back to n, e.g.
 // 	n.Left = finishcompare(n.Left, x, r, init)
 func finishcompare(n *ir.BinaryExpr, r ir.Node, init *ir.Nodes) ir.Node {
-	r = typecheck(r, ctxExpr)
-	r = conv(r, n.Type())
+	r = typecheck.Expr(r)
+	r = typecheck.Conv(r, n.Type())
 	r = walkexpr(r, init)
 	return r
 }
@@ -3926,7 +3863,7 @@ func wrapCall(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	origArgs := make([]ir.Node, len(n.Args))
 	var funcArgs []*ir.Field
 	for i, arg := range n.Args {
-		s := lookupN("a", i)
+		s := typecheck.LookupNum("a", i)
 		if !isBuiltinCall && arg.Op() == ir.OCONVNOP && arg.Type().IsUintptr() && arg.(*ir.ConvExpr).X.Type().IsUnsafePtr() {
 			origArgs[i] = arg
 			arg = arg.(*ir.ConvExpr).X
@@ -3937,8 +3874,8 @@ func wrapCall(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	t := ir.NewFuncType(base.Pos, nil, funcArgs, nil)
 
 	wrapCall_prgen++
-	sym := lookupN("wrap·", wrapCall_prgen)
-	fn := dclfunc(sym, t)
+	sym := typecheck.LookupNum("wrap·", wrapCall_prgen)
+	fn := typecheck.DeclFunc(sym, t)
 
 	args := ir.ParamNames(t.Type())
 	for i, origArg := range origArgs {
@@ -3954,32 +3891,14 @@ func wrapCall(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	}
 	fn.Body = []ir.Node{call}
 
-	funcbody()
+	typecheck.FinishFuncBody()
 
-	typecheckFunc(fn)
-	typecheckslice(fn.Body, ctxStmt)
-	Target.Decls = append(Target.Decls, fn)
+	typecheck.Func(fn)
+	typecheck.Stmts(fn.Body)
+	typecheck.Target.Decls = append(typecheck.Target.Decls, fn)
 
 	call = ir.NewCallExpr(base.Pos, ir.OCALL, fn.Nname, n.Args)
-	return walkexpr(typecheck(call, ctxStmt), init)
-}
-
-// substArgTypes substitutes the given list of types for
-// successive occurrences of the "any" placeholder in the
-// type syntax expression n.Type.
-// The result of substArgTypes MUST be assigned back to old, e.g.
-// 	n.Left = substArgTypes(n.Left, t1, t2)
-func substArgTypes(old *ir.Name, types_ ...*types.Type) *ir.Name {
-	n := old.CloneName()
-
-	for _, t := range types_ {
-		types.CalcSize(t)
-	}
-	n.SetType(types.SubstAny(n.Type(), &types_))
-	if len(types_) > 0 {
-		base.Fatalf("substArgTypes: too many argument types")
-	}
-	return n
+	return walkexpr(typecheck.Stmt(call), init)
 }
 
 // canMergeLoads reports whether the backend optimization passes for
@@ -4025,7 +3944,7 @@ func walkCheckPtrAlignment(n *ir.ConvExpr, init *ir.Nodes, count ir.Node) ir.Nod
 	}
 
 	n.X = cheapexpr(n.X, init)
-	init.Append(mkcall("checkptrAlignment", nil, init, convnop(n.X, types.Types[types.TUNSAFEPTR]), typename(elem), conv(count, types.Types[types.TUINTPTR])))
+	init.Append(mkcall("checkptrAlignment", nil, init, typecheck.ConvNop(n.X, types.Types[types.TUNSAFEPTR]), typename(elem), typecheck.Conv(count, types.Types[types.TUINTPTR])))
 	return n
 }
 
@@ -4077,7 +3996,7 @@ func walkCheckPtrArithmetic(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 			n := n.(*ir.ConvExpr)
 			if n.X.Type().IsUnsafePtr() {
 				n.X = cheapexpr(n.X, init)
-				originals = append(originals, convnop(n.X, types.Types[types.TUNSAFEPTR]))
+				originals = append(originals, typecheck.ConvNop(n.X, types.Types[types.TUNSAFEPTR]))
 			}
 		}
 	}
@@ -4085,10 +4004,10 @@ func walkCheckPtrArithmetic(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 
 	cheap := cheapexpr(n, init)
 
-	slice := mkdotargslice(types.NewSlice(types.Types[types.TUNSAFEPTR]), originals)
+	slice := typecheck.MakeDotArgs(types.NewSlice(types.Types[types.TUNSAFEPTR]), originals)
 	slice.SetEsc(ir.EscNone)
 
-	init.Append(mkcall("checkptrArithmetic", nil, init, convnop(cheap, types.Types[types.TUNSAFEPTR]), slice))
+	init.Append(mkcall("checkptrArithmetic", nil, init, typecheck.ConvNop(cheap, types.Types[types.TUNSAFEPTR]), slice))
 	// TODO(khr): Mark backing store of slice as dead. This will allow us to reuse
 	// the backing store for multiple calls to checkptrArithmetic.
 
@@ -4098,7 +4017,7 @@ func walkCheckPtrArithmetic(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 // appendWalkStmt typechecks and walks stmt and then appends it to init.
 func appendWalkStmt(init *ir.Nodes, stmt ir.Node) {
 	op := stmt.Op()
-	n := typecheck(stmt, ctxStmt)
+	n := typecheck.Stmt(stmt)
 	if op == ir.OAS || op == ir.OAS2 {
 		// If the assignment has side effects, walkexpr will append them
 		// directly to init for us, while walkstmt will wrap it in an OBLOCK.
diff --git a/src/cmd/compile/internal/typecheck/bexport.go b/src/cmd/compile/internal/typecheck/bexport.go
new file mode 100644
index 0000000000..4a84bb13fa
--- /dev/null
+++ b/src/cmd/compile/internal/typecheck/bexport.go
@@ -0,0 +1,102 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typecheck
+
+import "cmd/compile/internal/types"
+
+// ----------------------------------------------------------------------------
+// Export format
+
+// Tags. Must be < 0.
+const (
+	// Objects
+	packageTag = -(iota + 1)
+	constTag
+	typeTag
+	varTag
+	funcTag
+	endTag
+
+	// Types
+	namedTag
+	arrayTag
+	sliceTag
+	dddTag
+	structTag
+	pointerTag
+	signatureTag
+	interfaceTag
+	mapTag
+	chanTag
+
+	// Values
+	falseTag
+	trueTag
+	int64Tag
+	floatTag
+	fractionTag // not used by gc
+	complexTag
+	stringTag
+	nilTag
+	unknownTag // not used by gc (only appears in packages with errors)
+
+	// Type aliases
+	aliasTag
+)
+
+var predecl []*types.Type // initialized lazily
+
+func predeclared() []*types.Type {
+	if predecl == nil {
+		// initialize lazily to be sure that all
+		// elements have been initialized before
+		predecl = []*types.Type{
+			// basic types
+			types.Types[types.TBOOL],
+			types.Types[types.TINT],
+			types.Types[types.TINT8],
+			types.Types[types.TINT16],
+			types.Types[types.TINT32],
+			types.Types[types.TINT64],
+			types.Types[types.TUINT],
+			types.Types[types.TUINT8],
+			types.Types[types.TUINT16],
+			types.Types[types.TUINT32],
+			types.Types[types.TUINT64],
+			types.Types[types.TUINTPTR],
+			types.Types[types.TFLOAT32],
+			types.Types[types.TFLOAT64],
+			types.Types[types.TCOMPLEX64],
+			types.Types[types.TCOMPLEX128],
+			types.Types[types.TSTRING],
+
+			// basic type aliases
+			types.ByteType,
+			types.RuneType,
+
+			// error
+			types.ErrorType,
+
+			// untyped types
+			types.UntypedBool,
+			types.UntypedInt,
+			types.UntypedRune,
+			types.UntypedFloat,
+			types.UntypedComplex,
+			types.UntypedString,
+			types.Types[types.TNIL],
+
+			// package unsafe
+			types.Types[types.TUNSAFEPTR],
+
+			// invalid type (package contains errors)
+			types.Types[types.Txxx],
+
+			// any type, for builtin export data
+			types.Types[types.TANY],
+		}
+	}
+	return predecl
+}
diff --git a/src/cmd/compile/internal/typecheck/builtin.go b/src/cmd/compile/internal/typecheck/builtin.go
new file mode 100644
index 0000000000..d3c30fbf50
--- /dev/null
+++ b/src/cmd/compile/internal/typecheck/builtin.go
@@ -0,0 +1,344 @@
+// Code generated by mkbuiltin.go. DO NOT EDIT.
+
+package typecheck
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+)
+
+var runtimeDecls = [...]struct {
+	name string
+	tag  int
+	typ  int
+}{
+	{"newobject", funcTag, 4},
+	{"mallocgc", funcTag, 8},
+	{"panicdivide", funcTag, 9},
+	{"panicshift", funcTag, 9},
+	{"panicmakeslicelen", funcTag, 9},
+	{"panicmakeslicecap", funcTag, 9},
+	{"throwinit", funcTag, 9},
+	{"panicwrap", funcTag, 9},
+	{"gopanic", funcTag, 11},
+	{"gorecover", funcTag, 14},
+	{"goschedguarded", funcTag, 9},
+	{"goPanicIndex", funcTag, 16},
+	{"goPanicIndexU", funcTag, 18},
+	{"goPanicSliceAlen", funcTag, 16},
+	{"goPanicSliceAlenU", funcTag, 18},
+	{"goPanicSliceAcap", funcTag, 16},
+	{"goPanicSliceAcapU", funcTag, 18},
+	{"goPanicSliceB", funcTag, 16},
+	{"goPanicSliceBU", funcTag, 18},
+	{"goPanicSlice3Alen", funcTag, 16},
+	{"goPanicSlice3AlenU", funcTag, 18},
+	{"goPanicSlice3Acap", funcTag, 16},
+	{"goPanicSlice3AcapU", funcTag, 18},
+	{"goPanicSlice3B", funcTag, 16},
+	{"goPanicSlice3BU", funcTag, 18},
+	{"goPanicSlice3C", funcTag, 16},
+	{"goPanicSlice3CU", funcTag, 18},
+	{"printbool", funcTag, 19},
+	{"printfloat", funcTag, 21},
+	{"printint", funcTag, 23},
+	{"printhex", funcTag, 25},
+	{"printuint", funcTag, 25},
+	{"printcomplex", funcTag, 27},
+	{"printstring", funcTag, 29},
+	{"printpointer", funcTag, 30},
+	{"printuintptr", funcTag, 31},
+	{"printiface", funcTag, 30},
+	{"printeface", funcTag, 30},
+	{"printslice", funcTag, 30},
+	{"printnl", funcTag, 9},
+	{"printsp", funcTag, 9},
+	{"printlock", funcTag, 9},
+	{"printunlock", funcTag, 9},
+	{"concatstring2", funcTag, 34},
+	{"concatstring3", funcTag, 35},
+	{"concatstring4", funcTag, 36},
+	{"concatstring5", funcTag, 37},
+	{"concatstrings", funcTag, 39},
+	{"cmpstring", funcTag, 40},
+	{"intstring", funcTag, 43},
+	{"slicebytetostring", funcTag, 44},
+	{"slicebytetostringtmp", funcTag, 45},
+	{"slicerunetostring", funcTag, 48},
+	{"stringtoslicebyte", funcTag, 50},
+	{"stringtoslicerune", funcTag, 53},
+	{"slicecopy", funcTag, 54},
+	{"decoderune", funcTag, 55},
+	{"countrunes", funcTag, 56},
+	{"convI2I", funcTag, 57},
+	{"convT16", funcTag, 58},
+	{"convT32", funcTag, 58},
+	{"convT64", funcTag, 58},
+	{"convTstring", funcTag, 58},
+	{"convTslice", funcTag, 58},
+	{"convT2E", funcTag, 59},
+	{"convT2Enoptr", funcTag, 59},
+	{"convT2I", funcTag, 59},
+	{"convT2Inoptr", funcTag, 59},
+	{"assertE2I", funcTag, 57},
+	{"assertE2I2", funcTag, 60},
+	{"assertI2I", funcTag, 57},
+	{"assertI2I2", funcTag, 60},
+	{"panicdottypeE", funcTag, 61},
+	{"panicdottypeI", funcTag, 61},
+	{"panicnildottype", funcTag, 62},
+	{"ifaceeq", funcTag, 64},
+	{"efaceeq", funcTag, 64},
+	{"fastrand", funcTag, 66},
+	{"makemap64", funcTag, 68},
+	{"makemap", funcTag, 69},
+	{"makemap_small", funcTag, 70},
+	{"mapaccess1", funcTag, 71},
+	{"mapaccess1_fast32", funcTag, 72},
+	{"mapaccess1_fast64", funcTag, 72},
+	{"mapaccess1_faststr", funcTag, 72},
+	{"mapaccess1_fat", funcTag, 73},
+	{"mapaccess2", funcTag, 74},
+	{"mapaccess2_fast32", funcTag, 75},
+	{"mapaccess2_fast64", funcTag, 75},
+	{"mapaccess2_faststr", funcTag, 75},
+	{"mapaccess2_fat", funcTag, 76},
+	{"mapassign", funcTag, 71},
+	{"mapassign_fast32", funcTag, 72},
+	{"mapassign_fast32ptr", funcTag, 72},
+	{"mapassign_fast64", funcTag, 72},
+	{"mapassign_fast64ptr", funcTag, 72},
+	{"mapassign_faststr", funcTag, 72},
+	{"mapiterinit", funcTag, 77},
+	{"mapdelete", funcTag, 77},
+	{"mapdelete_fast32", funcTag, 78},
+	{"mapdelete_fast64", funcTag, 78},
+	{"mapdelete_faststr", funcTag, 78},
+	{"mapiternext", funcTag, 79},
+	{"mapclear", funcTag, 80},
+	{"makechan64", funcTag, 82},
+	{"makechan", funcTag, 83},
+	{"chanrecv1", funcTag, 85},
+	{"chanrecv2", funcTag, 86},
+	{"chansend1", funcTag, 88},
+	{"closechan", funcTag, 30},
+	{"writeBarrier", varTag, 90},
+	{"typedmemmove", funcTag, 91},
+	{"typedmemclr", funcTag, 92},
+	{"typedslicecopy", funcTag, 93},
+	{"selectnbsend", funcTag, 94},
+	{"selectnbrecv", funcTag, 95},
+	{"selectnbrecv2", funcTag, 97},
+	{"selectsetpc", funcTag, 98},
+	{"selectgo", funcTag, 99},
+	{"block", funcTag, 9},
+	{"makeslice", funcTag, 100},
+	{"makeslice64", funcTag, 101},
+	{"makeslicecopy", funcTag, 102},
+	{"growslice", funcTag, 104},
+	{"memmove", funcTag, 105},
+	{"memclrNoHeapPointers", funcTag, 106},
+	{"memclrHasPointers", funcTag, 106},
+	{"memequal", funcTag, 107},
+	{"memequal0", funcTag, 108},
+	{"memequal8", funcTag, 108},
+	{"memequal16", funcTag, 108},
+	{"memequal32", funcTag, 108},
+	{"memequal64", funcTag, 108},
+	{"memequal128", funcTag, 108},
+	{"f32equal", funcTag, 109},
+	{"f64equal", funcTag, 109},
+	{"c64equal", funcTag, 109},
+	{"c128equal", funcTag, 109},
+	{"strequal", funcTag, 109},
+	{"interequal", funcTag, 109},
+	{"nilinterequal", funcTag, 109},
+	{"memhash", funcTag, 110},
+	{"memhash0", funcTag, 111},
+	{"memhash8", funcTag, 111},
+	{"memhash16", funcTag, 111},
+	{"memhash32", funcTag, 111},
+	{"memhash64", funcTag, 111},
+	{"memhash128", funcTag, 111},
+	{"f32hash", funcTag, 111},
+	{"f64hash", funcTag, 111},
+	{"c64hash", funcTag, 111},
+	{"c128hash", funcTag, 111},
+	{"strhash", funcTag, 111},
+	{"interhash", funcTag, 111},
+	{"nilinterhash", funcTag, 111},
+	{"int64div", funcTag, 112},
+	{"uint64div", funcTag, 113},
+	{"int64mod", funcTag, 112},
+	{"uint64mod", funcTag, 113},
+	{"float64toint64", funcTag, 114},
+	{"float64touint64", funcTag, 115},
+	{"float64touint32", funcTag, 116},
+	{"int64tofloat64", funcTag, 117},
+	{"uint64tofloat64", funcTag, 118},
+	{"uint32tofloat64", funcTag, 119},
+	{"complex128div", funcTag, 120},
+	{"racefuncenter", funcTag, 31},
+	{"racefuncenterfp", funcTag, 9},
+	{"racefuncexit", funcTag, 9},
+	{"raceread", funcTag, 31},
+	{"racewrite", funcTag, 31},
+	{"racereadrange", funcTag, 121},
+	{"racewriterange", funcTag, 121},
+	{"msanread", funcTag, 121},
+	{"msanwrite", funcTag, 121},
+	{"msanmove", funcTag, 122},
+	{"checkptrAlignment", funcTag, 123},
+	{"checkptrArithmetic", funcTag, 125},
+	{"libfuzzerTraceCmp1", funcTag, 127},
+	{"libfuzzerTraceCmp2", funcTag, 129},
+	{"libfuzzerTraceCmp4", funcTag, 130},
+	{"libfuzzerTraceCmp8", funcTag, 131},
+	{"libfuzzerTraceConstCmp1", funcTag, 127},
+	{"libfuzzerTraceConstCmp2", funcTag, 129},
+	{"libfuzzerTraceConstCmp4", funcTag, 130},
+	{"libfuzzerTraceConstCmp8", funcTag, 131},
+	{"x86HasPOPCNT", varTag, 6},
+	{"x86HasSSE41", varTag, 6},
+	{"x86HasFMA", varTag, 6},
+	{"armHasVFPv4", varTag, 6},
+	{"arm64HasATOMICS", varTag, 6},
+}
+
+func runtimeTypes() []*types.Type {
+	var typs [132]*types.Type
+	typs[0] = types.ByteType
+	typs[1] = types.NewPtr(typs[0])
+	typs[2] = types.Types[types.TANY]
+	typs[3] = types.NewPtr(typs[2])
+	typs[4] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
+	typs[5] = types.Types[types.TUINTPTR]
+	typs[6] = types.Types[types.TBOOL]
+	typs[7] = types.Types[types.TUNSAFEPTR]
+	typs[8] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[6])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
+	typs[9] = NewFuncType(nil, nil, nil)
+	typs[10] = types.Types[types.TINTER]
+	typs[11] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[10])}, nil)
+	typs[12] = types.Types[types.TINT32]
+	typs[13] = types.NewPtr(typs[12])
+	typs[14] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[13])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[10])})
+	typs[15] = types.Types[types.TINT]
+	typs[16] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15])}, nil)
+	typs[17] = types.Types[types.TUINT]
+	typs[18] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[17]), ir.NewField(base.Pos, nil, nil, typs[15])}, nil)
+	typs[19] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])}, nil)
+	typs[20] = types.Types[types.TFLOAT64]
+	typs[21] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, nil)
+	typs[22] = types.Types[types.TINT64]
+	typs[23] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])}, nil)
+	typs[24] = types.Types[types.TUINT64]
+	typs[25] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])}, nil)
+	typs[26] = types.Types[types.TCOMPLEX128]
+	typs[27] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26])}, nil)
+	typs[28] = types.Types[types.TSTRING]
+	typs[29] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])}, nil)
+	typs[30] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])}, nil)
+	typs[31] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
+	typs[32] = types.NewArray(typs[0], 32)
+	typs[33] = types.NewPtr(typs[32])
+	typs[34] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[35] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[36] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[37] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[38] = types.NewSlice(typs[28])
+	typs[39] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[38])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[40] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
+	typs[41] = types.NewArray(typs[0], 4)
+	typs[42] = types.NewPtr(typs[41])
+	typs[43] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[42]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[44] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[45] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[46] = types.RuneType
+	typs[47] = types.NewSlice(typs[46])
+	typs[48] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[47])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])})
+	typs[49] = types.NewSlice(typs[0])
+	typs[50] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[33]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[49])})
+	typs[51] = types.NewArray(typs[46], 32)
+	typs[52] = types.NewPtr(typs[51])
+	typs[53] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[52]), ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[47])})
+	typs[54] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
+	typs[55] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[46]), ir.NewField(base.Pos, nil, nil, typs[15])})
+	typs[56] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[28])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
+	typs[57] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])})
+	typs[58] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
+	typs[59] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2])})
+	typs[60] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[2]), ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[61] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1])}, nil)
+	typs[62] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1])}, nil)
+	typs[63] = types.NewPtr(typs[5])
+	typs[64] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[63]), ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[65] = types.Types[types.TUINT32]
+	typs[66] = NewFuncType(nil, nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])})
+	typs[67] = types.NewMap(typs[2], typs[2])
+	typs[68] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
+	typs[69] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
+	typs[70] = NewFuncType(nil, nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[67])})
+	typs[71] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
+	typs[72] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
+	typs[73] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])})
+	typs[74] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[75] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[76] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[1])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[77] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
+	typs[78] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67]), ir.NewField(base.Pos, nil, nil, typs[2])}, nil)
+	typs[79] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
+	typs[80] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[67])}, nil)
+	typs[81] = types.NewChan(typs[2], types.Cboth)
+	typs[82] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[81])})
+	typs[83] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[81])})
+	typs[84] = types.NewChan(typs[2], types.Crecv)
+	typs[85] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[84]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
+	typs[86] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[84]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[87] = types.NewChan(typs[2], types.Csend)
+	typs[88] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[87]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
+	typs[89] = types.NewArray(typs[0], 3)
+	typs[90] = NewStructType([]*ir.Field{ir.NewField(base.Pos, Lookup("enabled"), nil, typs[6]), ir.NewField(base.Pos, Lookup("pad"), nil, typs[89]), ir.NewField(base.Pos, Lookup("needed"), nil, typs[6]), ir.NewField(base.Pos, Lookup("cgo"), nil, typs[6]), ir.NewField(base.Pos, Lookup("alignme"), nil, typs[24])})
+	typs[91] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
+	typs[92] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3])}, nil)
+	typs[93] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15])})
+	typs[94] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[87]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[95] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[84])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[96] = types.NewPtr(typs[6])
+	typs[97] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[96]), ir.NewField(base.Pos, nil, nil, typs[84])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[98] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[63])}, nil)
+	typs[99] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[63]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[6])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[100] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
+	typs[101] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
+	typs[102] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[15]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7])})
+	typs[103] = types.NewSlice(typs[2])
+	typs[104] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[103]), ir.NewField(base.Pos, nil, nil, typs[15])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[103])})
+	typs[105] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
+	typs[106] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
+	typs[107] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[108] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[3]), ir.NewField(base.Pos, nil, nil, typs[3])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[109] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[7])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[6])})
+	typs[110] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])})
+	typs[111] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[5])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5])})
+	typs[112] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22]), ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])})
+	typs[113] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24]), ir.NewField(base.Pos, nil, nil, typs[24])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])})
+	typs[114] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])})
+	typs[115] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])})
+	typs[116] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])})
+	typs[117] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[22])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
+	typs[118] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
+	typs[119] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[20])})
+	typs[120] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26]), ir.NewField(base.Pos, nil, nil, typs[26])}, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[26])})
+	typs[121] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
+	typs[122] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
+	typs[123] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[1]), ir.NewField(base.Pos, nil, nil, typs[5])}, nil)
+	typs[124] = types.NewSlice(typs[7])
+	typs[125] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[7]), ir.NewField(base.Pos, nil, nil, typs[124])}, nil)
+	typs[126] = types.Types[types.TUINT8]
+	typs[127] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[126]), ir.NewField(base.Pos, nil, nil, typs[126])}, nil)
+	typs[128] = types.Types[types.TUINT16]
+	typs[129] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[128]), ir.NewField(base.Pos, nil, nil, typs[128])}, nil)
+	typs[130] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[65]), ir.NewField(base.Pos, nil, nil, typs[65])}, nil)
+	typs[131] = NewFuncType(nil, []*ir.Field{ir.NewField(base.Pos, nil, nil, typs[24]), ir.NewField(base.Pos, nil, nil, typs[24])}, nil)
+	return typs[:]
+}
diff --git a/src/cmd/compile/internal/gc/builtin/runtime.go b/src/cmd/compile/internal/typecheck/builtin/runtime.go
similarity index 100%
rename from src/cmd/compile/internal/gc/builtin/runtime.go
rename to src/cmd/compile/internal/typecheck/builtin/runtime.go
diff --git a/src/cmd/compile/internal/gc/builtin_test.go b/src/cmd/compile/internal/typecheck/builtin_test.go
similarity index 97%
rename from src/cmd/compile/internal/gc/builtin_test.go
rename to src/cmd/compile/internal/typecheck/builtin_test.go
index df15ca5c7d..cc8d49730a 100644
--- a/src/cmd/compile/internal/gc/builtin_test.go
+++ b/src/cmd/compile/internal/typecheck/builtin_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package gc_test
+package typecheck
 
 import (
 	"bytes"
diff --git a/src/cmd/compile/internal/gc/const.go b/src/cmd/compile/internal/typecheck/const.go
similarity index 85%
rename from src/cmd/compile/internal/gc/const.go
rename to src/cmd/compile/internal/typecheck/const.go
index ad27f3ea44..54d70cb835 100644
--- a/src/cmd/compile/internal/gc/const.go
+++ b/src/cmd/compile/internal/typecheck/const.go
@@ -2,13 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package gc
+package typecheck
 
 import (
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/types"
-	"cmd/internal/src"
 	"fmt"
 	"go/constant"
 	"go/token"
@@ -16,6 +12,11 @@ import (
 	"math/big"
 	"strings"
 	"unicode"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
 )
 
 func roundFloat(v constant.Value, sz int64) constant.Value {
@@ -61,7 +62,7 @@ func trunccmplxlit(v constant.Value, t *types.Type) constant.Value {
 
 // TODO(mdempsky): Replace these with better APIs.
 func convlit(n ir.Node, t *types.Type) ir.Node    { return convlit1(n, t, false, nil) }
-func defaultlit(n ir.Node, t *types.Type) ir.Node { return convlit1(n, t, false, nil) }
+func DefaultLit(n ir.Node, t *types.Type) ir.Node { return convlit1(n, t, false, nil) }
 
 // convlit1 converts an untyped expression n to type t. If n already
 // has a type, convlit1 has no effect.
@@ -134,7 +135,7 @@ func convlit1(n ir.Node, t *types.Type, explicit bool, context func() string) ir
 	case ir.OPLUS, ir.ONEG, ir.OBITNOT, ir.ONOT, ir.OREAL, ir.OIMAG:
 		ot := operandType(n.Op(), t)
 		if ot == nil {
-			n = defaultlit(n, nil)
+			n = DefaultLit(n, nil)
 			break
 		}
 
@@ -150,7 +151,7 @@ func convlit1(n ir.Node, t *types.Type, explicit bool, context func() string) ir
 	case ir.OADD, ir.OSUB, ir.OMUL, ir.ODIV, ir.OMOD, ir.OOR, ir.OXOR, ir.OAND, ir.OANDNOT, ir.OOROR, ir.OANDAND, ir.OCOMPLEX:
 		ot := operandType(n.Op(), t)
 		if ot == nil {
-			n = defaultlit(n, nil)
+			n = DefaultLit(n, nil)
 			break
 		}
 
@@ -387,11 +388,11 @@ var tokenForOp = [...]token.Token{
 	ir.ORSH: token.SHR,
 }
 
-// evalConst returns a constant-evaluated expression equivalent to n.
-// If n is not a constant, evalConst returns n.
-// Otherwise, evalConst returns a new OLITERAL with the same value as n,
+// EvalConst returns a constant-evaluated expression equivalent to n.
+// If n is not a constant, EvalConst returns n.
+// Otherwise, EvalConst returns a new OLITERAL with the same value as n,
 // and with .Orig pointing back to n.
-func evalConst(n ir.Node) ir.Node {
+func EvalConst(n ir.Node) ir.Node {
 	// Pick off just the opcodes that can be constant evaluated.
 	switch n.Op() {
 	case ir.OPLUS, ir.ONEG, ir.OBITNOT, ir.ONOT:
@@ -402,7 +403,7 @@ func evalConst(n ir.Node) ir.Node {
 			if n.Type().IsUnsigned() {
 				prec = uint(n.Type().Size() * 8)
 			}
-			return origConst(n, constant.UnaryOp(tokenForOp[n.Op()], nl.Val(), prec))
+			return OrigConst(n, constant.UnaryOp(tokenForOp[n.Op()], nl.Val(), prec))
 		}
 
 	case ir.OADD, ir.OSUB, ir.OMUL, ir.ODIV, ir.OMOD, ir.OOR, ir.OXOR, ir.OAND, ir.OANDNOT:
@@ -427,21 +428,21 @@ func evalConst(n ir.Node) ir.Node {
 			if n.Op() == ir.ODIV && n.Type().IsInteger() {
 				tok = token.QUO_ASSIGN // integer division
 			}
-			return origConst(n, constant.BinaryOp(nl.Val(), tok, rval))
+			return OrigConst(n, constant.BinaryOp(nl.Val(), tok, rval))
 		}
 
 	case ir.OOROR, ir.OANDAND:
 		n := n.(*ir.LogicalExpr)
 		nl, nr := n.X, n.Y
 		if nl.Op() == ir.OLITERAL && nr.Op() == ir.OLITERAL {
-			return origConst(n, constant.BinaryOp(nl.Val(), tokenForOp[n.Op()], nr.Val()))
+			return OrigConst(n, constant.BinaryOp(nl.Val(), tokenForOp[n.Op()], nr.Val()))
 		}
 
 	case ir.OEQ, ir.ONE, ir.OLT, ir.OLE, ir.OGT, ir.OGE:
 		n := n.(*ir.BinaryExpr)
 		nl, nr := n.X, n.Y
 		if nl.Op() == ir.OLITERAL && nr.Op() == ir.OLITERAL {
-			return origBoolConst(n, constant.Compare(nl.Val(), tokenForOp[n.Op()], nr.Val()))
+			return OrigBool(n, constant.Compare(nl.Val(), tokenForOp[n.Op()], nr.Val()))
 		}
 
 	case ir.OLSH, ir.ORSH:
@@ -456,14 +457,14 @@ func evalConst(n ir.Node) ir.Node {
 				n.SetType(nil)
 				break
 			}
-			return origConst(n, constant.Shift(toint(nl.Val()), tokenForOp[n.Op()], uint(s)))
+			return OrigConst(n, constant.Shift(toint(nl.Val()), tokenForOp[n.Op()], uint(s)))
 		}
 
 	case ir.OCONV, ir.ORUNESTR:
 		n := n.(*ir.ConvExpr)
 		nl := n.X
 		if ir.OKForConst[n.Type().Kind()] && nl.Op() == ir.OLITERAL {
-			return origConst(n, convertVal(nl.Val(), n.Type(), true))
+			return OrigConst(n, convertVal(nl.Val(), n.Type(), true))
 		}
 
 	case ir.OCONVNOP:
@@ -472,7 +473,7 @@ func evalConst(n ir.Node) ir.Node {
 		if ir.OKForConst[n.Type().Kind()] && nl.Op() == ir.OLITERAL {
 			// set so n.Orig gets OCONV instead of OCONVNOP
 			n.SetOp(ir.OCONV)
-			return origConst(n, nl.Val())
+			return OrigConst(n, nl.Val())
 		}
 
 	case ir.OADDSTR:
@@ -494,7 +495,7 @@ func evalConst(n ir.Node) ir.Node {
 			for _, c := range s {
 				strs = append(strs, ir.StringVal(c))
 			}
-			return origConst(n, constant.MakeString(strings.Join(strs, "")))
+			return OrigConst(n, constant.MakeString(strings.Join(strs, "")))
 		}
 		newList := make([]ir.Node, 0, need)
 		for i := 0; i < len(s); i++ {
@@ -509,7 +510,7 @@ func evalConst(n ir.Node) ir.Node {
 
 				nl := ir.Copy(n).(*ir.AddStringExpr)
 				nl.List.Set(s[i:i2])
-				newList = append(newList, origConst(nl, constant.MakeString(strings.Join(strs, ""))))
+				newList = append(newList, OrigConst(nl, constant.MakeString(strings.Join(strs, ""))))
 				i = i2 - 1
 			} else {
 				newList = append(newList, s[i])
@@ -526,37 +527,37 @@ func evalConst(n ir.Node) ir.Node {
 		switch nl.Type().Kind() {
 		case types.TSTRING:
 			if ir.IsConst(nl, constant.String) {
-				return origIntConst(n, int64(len(ir.StringVal(nl))))
+				return OrigInt(n, int64(len(ir.StringVal(nl))))
 			}
 		case types.TARRAY:
 			if !anyCallOrChan(nl) {
-				return origIntConst(n, nl.Type().NumElem())
+				return OrigInt(n, nl.Type().NumElem())
 			}
 		}
 
 	case ir.OALIGNOF, ir.OOFFSETOF, ir.OSIZEOF:
 		n := n.(*ir.UnaryExpr)
-		return origIntConst(n, evalunsafe(n))
+		return OrigInt(n, evalunsafe(n))
 
 	case ir.OREAL:
 		n := n.(*ir.UnaryExpr)
 		nl := n.X
 		if nl.Op() == ir.OLITERAL {
-			return origConst(n, constant.Real(nl.Val()))
+			return OrigConst(n, constant.Real(nl.Val()))
 		}
 
 	case ir.OIMAG:
 		n := n.(*ir.UnaryExpr)
 		nl := n.X
 		if nl.Op() == ir.OLITERAL {
-			return origConst(n, constant.Imag(nl.Val()))
+			return OrigConst(n, constant.Imag(nl.Val()))
 		}
 
 	case ir.OCOMPLEX:
 		n := n.(*ir.BinaryExpr)
 		nl, nr := n.X, n.Y
 		if nl.Op() == ir.OLITERAL && nr.Op() == ir.OLITERAL {
-			return origConst(n, makeComplex(nl.Val(), nr.Val()))
+			return OrigConst(n, makeComplex(nl.Val(), nr.Val()))
 		}
 	}
 
@@ -598,8 +599,8 @@ var overflowNames = [...]string{
 	ir.OBITNOT: "bitwise complement",
 }
 
-// origConst returns an OLITERAL with orig n and value v.
-func origConst(n ir.Node, v constant.Value) ir.Node {
+// OrigConst returns an OLITERAL with orig n and value v.
+func OrigConst(n ir.Node, v constant.Value) ir.Node {
 	lno := ir.SetPos(n)
 	v = convertVal(v, n.Type(), false)
 	base.Pos = lno
@@ -623,12 +624,12 @@ func origConst(n ir.Node, v constant.Value) ir.Node {
 	return ir.NewConstExpr(v, n)
 }
 
-func origBoolConst(n ir.Node, v bool) ir.Node {
-	return origConst(n, constant.MakeBool(v))
+func OrigBool(n ir.Node, v bool) ir.Node {
+	return OrigConst(n, constant.MakeBool(v))
 }
 
-func origIntConst(n ir.Node, v int64) ir.Node {
-	return origConst(n, constant.MakeInt64(v))
+func OrigInt(n ir.Node, v int64) ir.Node {
+	return OrigConst(n, constant.MakeInt64(v))
 }
 
 // defaultlit on both nodes simultaneously;
@@ -722,12 +723,12 @@ func defaultType(t *types.Type) *types.Type {
 	return nil
 }
 
-// indexconst checks if Node n contains a constant expression
+// IndexConst checks if Node n contains a constant expression
 // representable as a non-negative int and returns its value.
 // If n is not a constant expression, not representable as an
 // integer, or negative, it returns -1. If n is too large, it
 // returns -2.
-func indexconst(n ir.Node) int64 {
+func IndexConst(n ir.Node) int64 {
 	if n.Op() != ir.OLITERAL {
 		return -1
 	}
@@ -862,3 +863,82 @@ func nodeAndVal(n ir.Node) string {
 	}
 	return show
 }
+
+// evalunsafe evaluates a package unsafe operation and returns the result.
+func evalunsafe(n ir.Node) int64 {
+	switch n.Op() {
+	case ir.OALIGNOF, ir.OSIZEOF:
+		n := n.(*ir.UnaryExpr)
+		n.X = Expr(n.X)
+		n.X = DefaultLit(n.X, nil)
+		tr := n.X.Type()
+		if tr == nil {
+			return 0
+		}
+		types.CalcSize(tr)
+		if n.Op() == ir.OALIGNOF {
+			return int64(tr.Align)
+		}
+		return tr.Width
+
+	case ir.OOFFSETOF:
+		// must be a selector.
+		n := n.(*ir.UnaryExpr)
+		if n.X.Op() != ir.OXDOT {
+			base.Errorf("invalid expression %v", n)
+			return 0
+		}
+		sel := n.X.(*ir.SelectorExpr)
+
+		// Remember base of selector to find it back after dot insertion.
+		// Since r->left may be mutated by typechecking, check it explicitly
+		// first to track it correctly.
+		sel.X = Expr(sel.X)
+		sbase := sel.X
+
+		tsel := Expr(sel)
+		n.X = tsel
+		if tsel.Type() == nil {
+			return 0
+		}
+		switch tsel.Op() {
+		case ir.ODOT, ir.ODOTPTR:
+			break
+		case ir.OCALLPART:
+			base.Errorf("invalid expression %v: argument is a method value", n)
+			return 0
+		default:
+			base.Errorf("invalid expression %v", n)
+			return 0
+		}
+
+		// Sum offsets for dots until we reach sbase.
+		var v int64
+		var next ir.Node
+		for r := tsel; r != sbase; r = next {
+			switch r.Op() {
+			case ir.ODOTPTR:
+				// For Offsetof(s.f), s may itself be a pointer,
+				// but accessing f must not otherwise involve
+				// indirection via embedded pointer types.
+				r := r.(*ir.SelectorExpr)
+				if r.X != sbase {
+					base.Errorf("invalid expression %v: selector implies indirection of embedded %v", n, r.X)
+					return 0
+				}
+				fallthrough
+			case ir.ODOT:
+				r := r.(*ir.SelectorExpr)
+				v += r.Offset
+				next = r.X
+			default:
+				ir.Dump("unsafenmagic", tsel)
+				base.Fatalf("impossible %v node after dot insertion", r.Op())
+			}
+		}
+		return v
+	}
+
+	base.Fatalf("unexpected op %v", n.Op())
+	return 0
+}
diff --git a/src/cmd/compile/internal/typecheck/dcl.go b/src/cmd/compile/internal/typecheck/dcl.go
new file mode 100644
index 0000000000..9f66d0fa17
--- /dev/null
+++ b/src/cmd/compile/internal/typecheck/dcl.go
@@ -0,0 +1,705 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typecheck
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
+)
+
+var DeclContext ir.Class // PEXTERN/PAUTO
+
+func AssignDefn(left []ir.Node, defn ir.Node) {
+	for _, n := range left {
+		if n.Sym() != nil {
+			n.Sym().SetUniq(true)
+		}
+	}
+
+	var nnew, nerr int
+	for i, n := range left {
+		if ir.IsBlank(n) {
+			continue
+		}
+		if !assignableName(n) {
+			base.ErrorfAt(defn.Pos(), "non-name %v on left side of :=", n)
+			nerr++
+			continue
+		}
+
+		if !n.Sym().Uniq() {
+			base.ErrorfAt(defn.Pos(), "%v repeated on left side of :=", n.Sym())
+			n.SetDiag(true)
+			nerr++
+			continue
+		}
+
+		n.Sym().SetUniq(false)
+		if n.Sym().Block == types.Block {
+			continue
+		}
+
+		nnew++
+		n := NewName(n.Sym())
+		Declare(n, DeclContext)
+		n.Defn = defn
+		defn.PtrInit().Append(ir.NewDecl(base.Pos, ir.ODCL, n))
+		left[i] = n
+	}
+
+	if nnew == 0 && nerr == 0 {
+		base.ErrorfAt(defn.Pos(), "no new variables on left side of :=")
+	}
+}
+
+// := declarations
+func assignableName(n ir.Node) bool {
+	switch n.Op() {
+	case ir.ONAME,
+		ir.ONONAME,
+		ir.OPACK,
+		ir.OTYPE,
+		ir.OLITERAL:
+		return n.Sym() != nil
+	}
+
+	return false
+}
+
+func DeclFunc(sym *types.Sym, tfn ir.Ntype) *ir.Func {
+	if tfn.Op() != ir.OTFUNC {
+		base.Fatalf("expected OTFUNC node, got %v", tfn)
+	}
+
+	fn := ir.NewFunc(base.Pos)
+	fn.Nname = ir.NewFuncNameAt(base.Pos, sym, fn)
+	fn.Nname.Defn = fn
+	fn.Nname.Ntype = tfn
+	ir.MarkFunc(fn.Nname)
+	StartFuncBody(fn)
+	fn.Nname.Ntype = typecheckNtype(fn.Nname.Ntype)
+	return fn
+}
+
+// declare variables from grammar
+// new_name_list (type | [type] = expr_list)
+func DeclVars(vl []*ir.Name, t ir.Ntype, el []ir.Node) []ir.Node {
+	var init []ir.Node
+	doexpr := len(el) > 0
+
+	if len(el) == 1 && len(vl) > 1 {
+		e := el[0]
+		as2 := ir.NewAssignListStmt(base.Pos, ir.OAS2, nil, nil)
+		as2.Rhs = []ir.Node{e}
+		for _, v := range vl {
+			as2.Lhs.Append(v)
+			Declare(v, DeclContext)
+			v.Ntype = t
+			v.Defn = as2
+			if ir.CurFunc != nil {
+				init = append(init, ir.NewDecl(base.Pos, ir.ODCL, v))
+			}
+		}
+
+		return append(init, as2)
+	}
+
+	for i, v := range vl {
+		var e ir.Node
+		if doexpr {
+			if i >= len(el) {
+				base.Errorf("assignment mismatch: %d variables but %d values", len(vl), len(el))
+				break
+			}
+			e = el[i]
+		}
+
+		Declare(v, DeclContext)
+		v.Ntype = t
+
+		if e != nil || ir.CurFunc != nil || ir.IsBlank(v) {
+			if ir.CurFunc != nil {
+				init = append(init, ir.NewDecl(base.Pos, ir.ODCL, v))
+			}
+			as := ir.NewAssignStmt(base.Pos, v, e)
+			init = append(init, as)
+			if e != nil {
+				v.Defn = as
+			}
+		}
+	}
+
+	if len(el) > len(vl) {
+		base.Errorf("assignment mismatch: %d variables but %d values", len(vl), len(el))
+	}
+	return init
+}
+
+// Declare records that Node n declares symbol n.Sym in the specified
+// declaration context.
+func Declare(n *ir.Name, ctxt ir.Class) {
+	if ir.IsBlank(n) {
+		return
+	}
+
+	s := n.Sym()
+
+	// kludgy: typecheckok means we're past parsing. Eg genwrapper may declare out of package names later.
+	if !inimport && !TypecheckAllowed && s.Pkg != types.LocalPkg {
+		base.ErrorfAt(n.Pos(), "cannot declare name %v", s)
+	}
+
+	gen := 0
+	if ctxt == ir.PEXTERN {
+		if s.Name == "init" {
+			base.ErrorfAt(n.Pos(), "cannot declare init - must be func")
+		}
+		if s.Name == "main" && s.Pkg.Name == "main" {
+			base.ErrorfAt(n.Pos(), "cannot declare main - must be func")
+		}
+		Target.Externs = append(Target.Externs, n)
+	} else {
+		if ir.CurFunc == nil && ctxt == ir.PAUTO {
+			base.Pos = n.Pos()
+			base.Fatalf("automatic outside function")
+		}
+		if ir.CurFunc != nil && ctxt != ir.PFUNC && n.Op() == ir.ONAME {
+			ir.CurFunc.Dcl = append(ir.CurFunc.Dcl, n)
+		}
+		if n.Op() == ir.OTYPE {
+			declare_typegen++
+			gen = declare_typegen
+		} else if n.Op() == ir.ONAME && ctxt == ir.PAUTO && !strings.Contains(s.Name, "·") {
+			vargen++
+			gen = vargen
+		}
+		types.Pushdcl(s)
+		n.Curfn = ir.CurFunc
+	}
+
+	if ctxt == ir.PAUTO {
+		n.SetFrameOffset(0)
+	}
+
+	if s.Block == types.Block {
+		// functype will print errors about duplicate function arguments.
+		// Don't repeat the error here.
+		if ctxt != ir.PPARAM && ctxt != ir.PPARAMOUT {
+			Redeclared(n.Pos(), s, "in this block")
+		}
+	}
+
+	s.Block = types.Block
+	s.Lastlineno = base.Pos
+	s.Def = n
+	n.Vargen = int32(gen)
+	n.Class_ = ctxt
+	if ctxt == ir.PFUNC {
+		n.Sym().SetFunc(true)
+	}
+
+	autoexport(n, ctxt)
+}
+
+// Export marks n for export (or reexport).
+func Export(n *ir.Name) {
+	if n.Sym().OnExportList() {
+		return
+	}
+	n.Sym().SetOnExportList(true)
+
+	if base.Flag.E != 0 {
+		fmt.Printf("export symbol %v\n", n.Sym())
+	}
+
+	Target.Exports = append(Target.Exports, n)
+}
+
+// Redeclared emits a diagnostic about symbol s being redeclared at pos.
+func Redeclared(pos src.XPos, s *types.Sym, where string) {
+	if !s.Lastlineno.IsKnown() {
+		pkgName := DotImportRefs[s.Def.(*ir.Ident)]
+		base.ErrorfAt(pos, "%v redeclared %s\n"+
+			"\t%v: previous declaration during import %q", s, where, base.FmtPos(pkgName.Pos()), pkgName.Pkg.Path)
+	} else {
+		prevPos := s.Lastlineno
+
+		// When an import and a declaration collide in separate files,
+		// present the import as the "redeclared", because the declaration
+		// is visible where the import is, but not vice versa.
+		// See issue 4510.
+		if s.Def == nil {
+			pos, prevPos = prevPos, pos
+		}
+
+		base.ErrorfAt(pos, "%v redeclared %s\n"+
+			"\t%v: previous declaration", s, where, base.FmtPos(prevPos))
+	}
+}
+
+// declare the function proper
+// and declare the arguments.
+// called in extern-declaration context
+// returns in auto-declaration context.
+func StartFuncBody(fn *ir.Func) {
+	// change the declaration context from extern to auto
+	funcStack = append(funcStack, funcStackEnt{ir.CurFunc, DeclContext})
+	ir.CurFunc = fn
+	DeclContext = ir.PAUTO
+
+	types.Markdcl()
+
+	if fn.Nname.Ntype != nil {
+		funcargs(fn.Nname.Ntype.(*ir.FuncType))
+	} else {
+		funcargs2(fn.Type())
+	}
+}
+
+// finish the body.
+// called in auto-declaration context.
+// returns in extern-declaration context.
+func FinishFuncBody() {
+	// change the declaration context from auto to previous context
+	types.Popdcl()
+	var e funcStackEnt
+	funcStack, e = funcStack[:len(funcStack)-1], funcStack[len(funcStack)-1]
+	ir.CurFunc, DeclContext = e.curfn, e.dclcontext
+}
+
+func CheckFuncStack() {
+	if len(funcStack) != 0 {
+		base.Fatalf("funcStack is non-empty: %v", len(funcStack))
+	}
+}
+
+// turn a parsed function declaration into a type
+func NewFuncType(nrecv *ir.Field, nparams, nresults []*ir.Field) *types.Type {
+	funarg := func(n *ir.Field) *types.Field {
+		lno := base.Pos
+		base.Pos = n.Pos
+
+		if n.Ntype != nil {
+			n.Type = typecheckNtype(n.Ntype).Type()
+			n.Ntype = nil
+		}
+
+		f := types.NewField(n.Pos, n.Sym, n.Type)
+		f.SetIsDDD(n.IsDDD)
+		if n.Decl != nil {
+			n.Decl.SetType(f.Type)
+			f.Nname = n.Decl
+		}
+
+		base.Pos = lno
+		return f
+	}
+	funargs := func(nn []*ir.Field) []*types.Field {
+		res := make([]*types.Field, len(nn))
+		for i, n := range nn {
+			res[i] = funarg(n)
+		}
+		return res
+	}
+
+	var recv *types.Field
+	if nrecv != nil {
+		recv = funarg(nrecv)
+	}
+
+	t := types.NewSignature(types.LocalPkg, recv, funargs(nparams), funargs(nresults))
+	checkdupfields("argument", t.Recvs().FieldSlice(), t.Params().FieldSlice(), t.Results().FieldSlice())
+	return t
+}
+
+// convert a parsed id/type list into
+// a type for struct/interface/arglist
+func NewStructType(l []*ir.Field) *types.Type {
+	lno := base.Pos
+
+	fields := make([]*types.Field, len(l))
+	for i, n := range l {
+		base.Pos = n.Pos
+
+		if n.Ntype != nil {
+			n.Type = typecheckNtype(n.Ntype).Type()
+			n.Ntype = nil
+		}
+		f := types.NewField(n.Pos, n.Sym, n.Type)
+		if n.Embedded {
+			checkembeddedtype(n.Type)
+			f.Embedded = 1
+		}
+		f.Note = n.Note
+		fields[i] = f
+	}
+	checkdupfields("field", fields)
+
+	base.Pos = lno
+	return types.NewStruct(types.LocalPkg, fields)
+}
+
+// Add a method, declared as a function.
+// - msym is the method symbol
+// - t is function type (with receiver)
+// Returns a pointer to the existing or added Field; or nil if there's an error.
+func addmethod(n *ir.Func, msym *types.Sym, t *types.Type, local, nointerface bool) *types.Field {
+	if msym == nil {
+		base.Fatalf("no method symbol")
+	}
+
+	// get parent type sym
+	rf := t.Recv() // ptr to this structure
+	if rf == nil {
+		base.Errorf("missing receiver")
+		return nil
+	}
+
+	mt := types.ReceiverBaseType(rf.Type)
+	if mt == nil || mt.Sym() == nil {
+		pa := rf.Type
+		t := pa
+		if t != nil && t.IsPtr() {
+			if t.Sym() != nil {
+				base.Errorf("invalid receiver type %v (%v is a pointer type)", pa, t)
+				return nil
+			}
+			t = t.Elem()
+		}
+
+		switch {
+		case t == nil || t.Broke():
+			// rely on typecheck having complained before
+		case t.Sym() == nil:
+			base.Errorf("invalid receiver type %v (%v is not a defined type)", pa, t)
+		case t.IsPtr():
+			base.Errorf("invalid receiver type %v (%v is a pointer type)", pa, t)
+		case t.IsInterface():
+			base.Errorf("invalid receiver type %v (%v is an interface type)", pa, t)
+		default:
+			// Should have picked off all the reasons above,
+			// but just in case, fall back to generic error.
+			base.Errorf("invalid receiver type %v (%L / %L)", pa, pa, t)
+		}
+		return nil
+	}
+
+	if local && mt.Sym().Pkg != types.LocalPkg {
+		base.Errorf("cannot define new methods on non-local type %v", mt)
+		return nil
+	}
+
+	if msym.IsBlank() {
+		return nil
+	}
+
+	if mt.IsStruct() {
+		for _, f := range mt.Fields().Slice() {
+			if f.Sym == msym {
+				base.Errorf("type %v has both field and method named %v", mt, msym)
+				f.SetBroke(true)
+				return nil
+			}
+		}
+	}
+
+	for _, f := range mt.Methods().Slice() {
+		if msym.Name != f.Sym.Name {
+			continue
+		}
+		// types.Identical only checks that incoming and result parameters match,
+		// so explicitly check that the receiver parameters match too.
+		if !types.Identical(t, f.Type) || !types.Identical(t.Recv().Type, f.Type.Recv().Type) {
+			base.Errorf("method redeclared: %v.%v\n\t%v\n\t%v", mt, msym, f.Type, t)
+		}
+		return f
+	}
+
+	f := types.NewField(base.Pos, msym, t)
+	f.Nname = n.Nname
+	f.SetNointerface(nointerface)
+
+	mt.Methods().Append(f)
+	return f
+}
+
+func autoexport(n *ir.Name, ctxt ir.Class) {
+	if n.Sym().Pkg != types.LocalPkg {
+		return
+	}
+	if (ctxt != ir.PEXTERN && ctxt != ir.PFUNC) || DeclContext != ir.PEXTERN {
+		return
+	}
+	if n.Type() != nil && n.Type().IsKind(types.TFUNC) && ir.IsMethod(n) {
+		return
+	}
+
+	if types.IsExported(n.Sym().Name) || initname(n.Sym().Name) {
+		Export(n)
+	}
+	if base.Flag.AsmHdr != "" && !n.Sym().Asm() {
+		n.Sym().SetAsm(true)
+		Target.Asms = append(Target.Asms, n)
+	}
+}
+
+// checkdupfields emits errors for duplicately named fields or methods in
+// a list of struct or interface types.
+func checkdupfields(what string, fss ...[]*types.Field) {
+	seen := make(map[*types.Sym]bool)
+	for _, fs := range fss {
+		for _, f := range fs {
+			if f.Sym == nil || f.Sym.IsBlank() {
+				continue
+			}
+			if seen[f.Sym] {
+				base.ErrorfAt(f.Pos, "duplicate %s %s", what, f.Sym.Name)
+				continue
+			}
+			seen[f.Sym] = true
+		}
+	}
+}
+
+// structs, functions, and methods.
+// they don't belong here, but where do they belong?
+func checkembeddedtype(t *types.Type) {
+	if t == nil {
+		return
+	}
+
+	if t.Sym() == nil && t.IsPtr() {
+		t = t.Elem()
+		if t.IsInterface() {
+			base.Errorf("embedded type cannot be a pointer to interface")
+		}
+	}
+
+	if t.IsPtr() || t.IsUnsafePtr() {
+		base.Errorf("embedded type cannot be a pointer")
+	} else if t.Kind() == types.TFORW && !t.ForwardType().Embedlineno.IsKnown() {
+		t.ForwardType().Embedlineno = base.Pos
+	}
+}
+
+// declare individual names - var, typ, const
+
+var declare_typegen int
+
+func fakeRecvField() *types.Field {
+	return types.NewField(src.NoXPos, nil, types.FakeRecvType())
+}
+
+var funcStack []funcStackEnt // stack of previous values of Curfn/dclcontext
+
+type funcStackEnt struct {
+	curfn      *ir.Func
+	dclcontext ir.Class
+}
+
+func funcarg(n *ir.Field, ctxt ir.Class) {
+	if n.Sym == nil {
+		return
+	}
+
+	name := ir.NewNameAt(n.Pos, n.Sym)
+	n.Decl = name
+	name.Ntype = n.Ntype
+	name.SetIsDDD(n.IsDDD)
+	Declare(name, ctxt)
+
+	vargen++
+	n.Decl.Vargen = int32(vargen)
+}
+
+func funcarg2(f *types.Field, ctxt ir.Class) {
+	if f.Sym == nil {
+		return
+	}
+	n := ir.NewNameAt(f.Pos, f.Sym)
+	f.Nname = n
+	n.SetType(f.Type)
+	n.SetIsDDD(f.IsDDD())
+	Declare(n, ctxt)
+}
+
+func funcargs(nt *ir.FuncType) {
+	if nt.Op() != ir.OTFUNC {
+		base.Fatalf("funcargs %v", nt.Op())
+	}
+
+	// re-start the variable generation number
+	// we want to use small numbers for the return variables,
+	// so let them have the chunk starting at 1.
+	//
+	// TODO(mdempsky): This is ugly, and only necessary because
+	// esc.go uses Vargen to figure out result parameters' index
+	// within the result tuple.
+	vargen = len(nt.Results)
+
+	// declare the receiver and in arguments.
+	if nt.Recv != nil {
+		funcarg(nt.Recv, ir.PPARAM)
+	}
+	for _, n := range nt.Params {
+		funcarg(n, ir.PPARAM)
+	}
+
+	oldvargen := vargen
+	vargen = 0
+
+	// declare the out arguments.
+	gen := len(nt.Params)
+	for _, n := range nt.Results {
+		if n.Sym == nil {
+			// Name so that escape analysis can track it. ~r stands for 'result'.
+			n.Sym = LookupNum("~r", gen)
+			gen++
+		}
+		if n.Sym.IsBlank() {
+			// Give it a name so we can assign to it during return. ~b stands for 'blank'.
+			// The name must be different from ~r above because if you have
+			//	func f() (_ int)
+			//	func g() int
+			// f is allowed to use a plain 'return' with no arguments, while g is not.
+			// So the two cases must be distinguished.
+			n.Sym = LookupNum("~b", gen)
+			gen++
+		}
+
+		funcarg(n, ir.PPARAMOUT)
+	}
+
+	vargen = oldvargen
+}
+
+// Same as funcargs, except run over an already constructed TFUNC.
+// This happens during import, where the hidden_fndcl rule has
+// used functype directly to parse the function's type.
+func funcargs2(t *types.Type) {
+	if t.Kind() != types.TFUNC {
+		base.Fatalf("funcargs2 %v", t)
+	}
+
+	for _, f := range t.Recvs().Fields().Slice() {
+		funcarg2(f, ir.PPARAM)
+	}
+	for _, f := range t.Params().Fields().Slice() {
+		funcarg2(f, ir.PPARAM)
+	}
+	for _, f := range t.Results().Fields().Slice() {
+		funcarg2(f, ir.PPARAMOUT)
+	}
+}
+
+func initname(s string) bool {
+	return s == "init"
+}
+
+func tointerface(nmethods []*ir.Field) *types.Type {
+	if len(nmethods) == 0 {
+		return types.Types[types.TINTER]
+	}
+
+	lno := base.Pos
+
+	methods := make([]*types.Field, len(nmethods))
+	for i, n := range nmethods {
+		base.Pos = n.Pos
+		if n.Ntype != nil {
+			n.Type = typecheckNtype(n.Ntype).Type()
+			n.Ntype = nil
+		}
+		methods[i] = types.NewField(n.Pos, n.Sym, n.Type)
+	}
+
+	base.Pos = lno
+	return types.NewInterface(types.LocalPkg, methods)
+}
+
+var vargen int
+
+func Temp(t *types.Type) *ir.Name {
+	return TempAt(base.Pos, ir.CurFunc, t)
+}
+
+// make a new Node off the books
+func TempAt(pos src.XPos, curfn *ir.Func, t *types.Type) *ir.Name {
+	if curfn == nil {
+		base.Fatalf("no curfn for tempAt")
+	}
+	if curfn.Op() == ir.OCLOSURE {
+		ir.Dump("tempAt", curfn)
+		base.Fatalf("adding tempAt to wrong closure function")
+	}
+	if t == nil {
+		base.Fatalf("tempAt called with nil type")
+	}
+
+	s := &types.Sym{
+		Name: autotmpname(len(curfn.Dcl)),
+		Pkg:  types.LocalPkg,
+	}
+	n := ir.NewNameAt(pos, s)
+	s.Def = n
+	n.SetType(t)
+	n.Class_ = ir.PAUTO
+	n.SetEsc(ir.EscNever)
+	n.Curfn = curfn
+	n.SetUsed(true)
+	n.SetAutoTemp(true)
+	curfn.Dcl = append(curfn.Dcl, n)
+
+	types.CalcSize(t)
+
+	return n
+}
+
+// autotmpname returns the name for an autotmp variable numbered n.
+func autotmpname(n int) string {
+	// Give each tmp a different name so that they can be registerized.
+	// Add a preceding . to avoid clashing with legal names.
+	const prefix = ".autotmp_"
+	// Start with a buffer big enough to hold a large n.
+	b := []byte(prefix + "      ")[:len(prefix)]
+	b = strconv.AppendInt(b, int64(n), 10)
+	return types.InternString(b)
+}
+
+// f is method type, with receiver.
+// return function type, receiver as first argument (or not).
+func NewMethodType(f *types.Type, receiver *types.Type) *types.Type {
+	inLen := f.Params().Fields().Len()
+	if receiver != nil {
+		inLen++
+	}
+	in := make([]*ir.Field, 0, inLen)
+
+	if receiver != nil {
+		d := ir.NewField(base.Pos, nil, nil, receiver)
+		in = append(in, d)
+	}
+
+	for _, t := range f.Params().Fields().Slice() {
+		d := ir.NewField(base.Pos, nil, nil, t.Type)
+		d.IsDDD = t.IsDDD()
+		in = append(in, d)
+	}
+
+	outLen := f.Results().Fields().Len()
+	out := make([]*ir.Field, 0, outLen)
+	for _, t := range f.Results().Fields().Slice() {
+		d := ir.NewField(base.Pos, nil, nil, t.Type)
+		out = append(out, d)
+	}
+
+	return NewFuncType(nil, in, out)
+}
diff --git a/src/cmd/compile/internal/typecheck/export.go b/src/cmd/compile/internal/typecheck/export.go
new file mode 100644
index 0000000000..381a28e3ed
--- /dev/null
+++ b/src/cmd/compile/internal/typecheck/export.go
@@ -0,0 +1,79 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typecheck
+
+import (
+	"go/constant"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
+)
+
+// importalias declares symbol s as an imported type alias with type t.
+// ipkg is the package being imported
+func importalias(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type) *ir.Name {
+	return importobj(ipkg, pos, s, ir.OTYPE, ir.PEXTERN, t)
+}
+
+// importconst declares symbol s as an imported constant with type t and value val.
+// ipkg is the package being imported
+func importconst(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type, val constant.Value) *ir.Name {
+	n := importobj(ipkg, pos, s, ir.OLITERAL, ir.PEXTERN, t)
+	n.SetVal(val)
+	return n
+}
+
+// importfunc declares symbol s as an imported function with type t.
+// ipkg is the package being imported
+func importfunc(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type) *ir.Name {
+	n := importobj(ipkg, pos, s, ir.ONAME, ir.PFUNC, t)
+
+	fn := ir.NewFunc(pos)
+	fn.SetType(t)
+	n.SetFunc(fn)
+	fn.Nname = n
+
+	return n
+}
+
+// importobj declares symbol s as an imported object representable by op.
+// ipkg is the package being imported
+func importobj(ipkg *types.Pkg, pos src.XPos, s *types.Sym, op ir.Op, ctxt ir.Class, t *types.Type) *ir.Name {
+	n := importsym(ipkg, pos, s, op, ctxt)
+	n.SetType(t)
+	if ctxt == ir.PFUNC {
+		n.Sym().SetFunc(true)
+	}
+	return n
+}
+
+func importsym(ipkg *types.Pkg, pos src.XPos, s *types.Sym, op ir.Op, ctxt ir.Class) *ir.Name {
+	if n := s.PkgDef(); n != nil {
+		base.Fatalf("importsym of symbol that already exists: %v", n)
+	}
+
+	n := ir.NewDeclNameAt(pos, op, s)
+	n.Class_ = ctxt // TODO(mdempsky): Move this into NewDeclNameAt too?
+	s.SetPkgDef(n)
+	s.Importdef = ipkg
+	return n
+}
+
+// importtype returns the named type declared by symbol s.
+// If no such type has been declared yet, a forward declaration is returned.
+// ipkg is the package being imported
+func importtype(ipkg *types.Pkg, pos src.XPos, s *types.Sym) *ir.Name {
+	n := importsym(ipkg, pos, s, ir.OTYPE, ir.PEXTERN)
+	n.SetType(types.NewNamed(n))
+	return n
+}
+
+// importvar declares symbol s as an imported variable with type t.
+// ipkg is the package being imported
+func importvar(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type) *ir.Name {
+	return importobj(ipkg, pos, s, ir.ONAME, ir.PEXTERN, t)
+}
diff --git a/src/cmd/compile/internal/typecheck/func.go b/src/cmd/compile/internal/typecheck/func.go
new file mode 100644
index 0000000000..4675de6cad
--- /dev/null
+++ b/src/cmd/compile/internal/typecheck/func.go
@@ -0,0 +1,398 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typecheck
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+
+	"fmt"
+)
+
+// package all the arguments that match a ... T parameter into a []T.
+func MakeDotArgs(typ *types.Type, args []ir.Node) ir.Node {
+	var n ir.Node
+	if len(args) == 0 {
+		n = NodNil()
+		n.SetType(typ)
+	} else {
+		lit := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(typ).(ir.Ntype), nil)
+		lit.List.Append(args...)
+		lit.SetImplicit(true)
+		n = lit
+	}
+
+	n = Expr(n)
+	if n.Type() == nil {
+		base.Fatalf("mkdotargslice: typecheck failed")
+	}
+	return n
+}
+
+// FixVariadicCall rewrites calls to variadic functions to use an
+// explicit ... argument if one is not already present.
+func FixVariadicCall(call *ir.CallExpr) {
+	fntype := call.X.Type()
+	if !fntype.IsVariadic() || call.IsDDD {
+		return
+	}
+
+	vi := fntype.NumParams() - 1
+	vt := fntype.Params().Field(vi).Type
+
+	args := call.Args
+	extra := args[vi:]
+	slice := MakeDotArgs(vt, extra)
+	for i := range extra {
+		extra[i] = nil // allow GC
+	}
+
+	call.Args.Set(append(args[:vi], slice))
+	call.IsDDD = true
+}
+
+// ClosureType returns the struct type used to hold all the information
+// needed in the closure for clo (clo must be a OCLOSURE node).
+// The address of a variable of the returned type can be cast to a func.
+func ClosureType(clo *ir.ClosureExpr) *types.Type {
+	// Create closure in the form of a composite literal.
+	// supposing the closure captures an int i and a string s
+	// and has one float64 argument and no results,
+	// the generated code looks like:
+	//
+	//	clos = &struct{.F uintptr; i *int; s *string}{func.1, &i, &s}
+	//
+	// The use of the struct provides type information to the garbage
+	// collector so that it can walk the closure. We could use (in this case)
+	// [3]unsafe.Pointer instead, but that would leave the gc in the dark.
+	// The information appears in the binary in the form of type descriptors;
+	// the struct is unnamed so that closures in multiple packages with the
+	// same struct type can share the descriptor.
+	fields := []*ir.Field{
+		ir.NewField(base.Pos, Lookup(".F"), nil, types.Types[types.TUINTPTR]),
+	}
+	for _, v := range clo.Func.ClosureVars {
+		typ := v.Type()
+		if !v.Byval() {
+			typ = types.NewPtr(typ)
+		}
+		fields = append(fields, ir.NewField(base.Pos, v.Sym(), nil, typ))
+	}
+	typ := NewStructType(fields)
+	typ.SetNoalg(true)
+	return typ
+}
+
+// PartialCallType returns the struct type used to hold all the information
+// needed in the closure for n (n must be a OCALLPART node).
+// The address of a variable of the returned type can be cast to a func.
+func PartialCallType(n *ir.CallPartExpr) *types.Type {
+	t := NewStructType([]*ir.Field{
+		ir.NewField(base.Pos, Lookup("F"), nil, types.Types[types.TUINTPTR]),
+		ir.NewField(base.Pos, Lookup("R"), nil, n.X.Type()),
+	})
+	t.SetNoalg(true)
+	return t
+}
+
+// CaptureVars is called in a separate phase after all typechecking is done.
+// It decides whether each variable captured by a closure should be captured
+// by value or by reference.
+// We use value capturing for values <= 128 bytes that are never reassigned
+// after capturing (effectively constant).
+func CaptureVars(fn *ir.Func) {
+	lno := base.Pos
+	base.Pos = fn.Pos()
+	cvars := fn.ClosureVars
+	out := cvars[:0]
+	for _, v := range cvars {
+		if v.Type() == nil {
+			// If v.Type is nil, it means v looked like it
+			// was going to be used in the closure, but
+			// isn't. This happens in struct literals like
+			// s{f: x} where we can't distinguish whether
+			// f is a field identifier or expression until
+			// resolving s.
+			continue
+		}
+		out = append(out, v)
+
+		// type check the & of closed variables outside the closure,
+		// so that the outer frame also grabs them and knows they escape.
+		types.CalcSize(v.Type())
+
+		var outer ir.Node
+		outer = v.Outer
+		outermost := v.Defn.(*ir.Name)
+
+		// out parameters will be assigned to implicitly upon return.
+		if outermost.Class_ != ir.PPARAMOUT && !outermost.Name().Addrtaken() && !outermost.Name().Assigned() && v.Type().Width <= 128 {
+			v.SetByval(true)
+		} else {
+			outermost.Name().SetAddrtaken(true)
+			outer = NodAddr(outer)
+		}
+
+		if base.Flag.LowerM > 1 {
+			var name *types.Sym
+			if v.Curfn != nil && v.Curfn.Nname != nil {
+				name = v.Curfn.Sym()
+			}
+			how := "ref"
+			if v.Byval() {
+				how = "value"
+			}
+			base.WarnfAt(v.Pos(), "%v capturing by %s: %v (addr=%v assign=%v width=%d)", name, how, v.Sym(), outermost.Name().Addrtaken(), outermost.Name().Assigned(), int32(v.Type().Width))
+		}
+
+		outer = Expr(outer)
+		fn.ClosureEnter.Append(outer)
+	}
+
+	fn.ClosureVars = out
+	base.Pos = lno
+}
+
+// typecheckclosure typechecks an OCLOSURE node. It also creates the named
+// function associated with the closure.
+// TODO: This creation of the named function should probably really be done in a
+// separate pass from type-checking.
+func typecheckclosure(clo *ir.ClosureExpr, top int) {
+	fn := clo.Func
+	// Set current associated iota value, so iota can be used inside
+	// function in ConstSpec, see issue #22344
+	if x := getIotaValue(); x >= 0 {
+		fn.Iota = x
+	}
+
+	fn.ClosureType = check(fn.ClosureType, ctxType)
+	clo.SetType(fn.ClosureType.Type())
+	fn.SetClosureCalled(top&ctxCallee != 0)
+
+	// Do not typecheck fn twice, otherwise, we will end up pushing
+	// fn to Target.Decls multiple times, causing initLSym called twice.
+	// See #30709
+	if fn.Typecheck() == 1 {
+		return
+	}
+
+	for _, ln := range fn.ClosureVars {
+		n := ln.Defn
+		if !n.Name().Captured() {
+			n.Name().SetCaptured(true)
+			if n.Name().Decldepth == 0 {
+				base.Fatalf("typecheckclosure: var %v does not have decldepth assigned", n)
+			}
+
+			// Ignore assignments to the variable in straightline code
+			// preceding the first capturing by a closure.
+			if n.Name().Decldepth == decldepth {
+				n.Name().SetAssigned(false)
+			}
+		}
+	}
+
+	fn.Nname.SetSym(closurename(ir.CurFunc))
+	ir.MarkFunc(fn.Nname)
+	Func(fn)
+
+	// Type check the body now, but only if we're inside a function.
+	// At top level (in a variable initialization: curfn==nil) we're not
+	// ready to type check code yet; we'll check it later, because the
+	// underlying closure function we create is added to Target.Decls.
+	if ir.CurFunc != nil && clo.Type() != nil {
+		oldfn := ir.CurFunc
+		ir.CurFunc = fn
+		olddd := decldepth
+		decldepth = 1
+		Stmts(fn.Body)
+		decldepth = olddd
+		ir.CurFunc = oldfn
+	}
+
+	Target.Decls = append(Target.Decls, fn)
+}
+
+// Lazy typechecking of imported bodies. For local functions, caninl will set ->typecheck
+// because they're a copy of an already checked body.
+func ImportedBody(fn *ir.Func) {
+	lno := ir.SetPos(fn.Nname)
+
+	ImportBody(fn)
+
+	// typecheckinl is only for imported functions;
+	// their bodies may refer to unsafe as long as the package
+	// was marked safe during import (which was checked then).
+	// the ->inl of a local function has been typechecked before caninl copied it.
+	pkg := fnpkg(fn.Nname)
+
+	if pkg == types.LocalPkg || pkg == nil {
+		return // typecheckinl on local function
+	}
+
+	if base.Flag.LowerM > 2 || base.Debug.Export != 0 {
+		fmt.Printf("typecheck import [%v] %L { %v }\n", fn.Sym(), fn, ir.Nodes(fn.Inl.Body))
+	}
+
+	savefn := ir.CurFunc
+	ir.CurFunc = fn
+	Stmts(fn.Inl.Body)
+	ir.CurFunc = savefn
+
+	// During expandInline (which imports fn.Func.Inl.Body),
+	// declarations are added to fn.Func.Dcl by funcHdr(). Move them
+	// to fn.Func.Inl.Dcl for consistency with how local functions
+	// behave. (Append because typecheckinl may be called multiple
+	// times.)
+	fn.Inl.Dcl = append(fn.Inl.Dcl, fn.Dcl...)
+	fn.Dcl = nil
+
+	base.Pos = lno
+}
+
+// Get the function's package. For ordinary functions it's on the ->sym, but for imported methods
+// the ->sym can be re-used in the local package, so peel it off the receiver's type.
+func fnpkg(fn *ir.Name) *types.Pkg {
+	if ir.IsMethod(fn) {
+		// method
+		rcvr := fn.Type().Recv().Type
+
+		if rcvr.IsPtr() {
+			rcvr = rcvr.Elem()
+		}
+		if rcvr.Sym() == nil {
+			base.Fatalf("receiver with no sym: [%v] %L  (%v)", fn.Sym(), fn, rcvr)
+		}
+		return rcvr.Sym().Pkg
+	}
+
+	// non-method
+	return fn.Sym().Pkg
+}
+
+// CaptureVarsComplete is set to true when the capturevars phase is done.
+var CaptureVarsComplete bool
+
+// closurename generates a new unique name for a closure within
+// outerfunc.
+func closurename(outerfunc *ir.Func) *types.Sym {
+	outer := "glob."
+	prefix := "func"
+	gen := &globClosgen
+
+	if outerfunc != nil {
+		if outerfunc.OClosure != nil {
+			prefix = ""
+		}
+
+		outer = ir.FuncName(outerfunc)
+
+		// There may be multiple functions named "_". In those
+		// cases, we can't use their individual Closgens as it
+		// would lead to name clashes.
+		if !ir.IsBlank(outerfunc.Nname) {
+			gen = &outerfunc.Closgen
+		}
+	}
+
+	*gen++
+	return Lookup(fmt.Sprintf("%s.%s%d", outer, prefix, *gen))
+}
+
+// globClosgen is like Func.Closgen, but for the global scope.
+var globClosgen int32
+
+// makepartialcall returns a DCLFUNC node representing the wrapper function (*-fm) needed
+// for partial calls.
+func makepartialcall(dot *ir.SelectorExpr, t0 *types.Type, meth *types.Sym) *ir.Func {
+	rcvrtype := dot.X.Type()
+	sym := ir.MethodSymSuffix(rcvrtype, meth, "-fm")
+
+	if sym.Uniq() {
+		return sym.Def.(*ir.Func)
+	}
+	sym.SetUniq(true)
+
+	savecurfn := ir.CurFunc
+	saveLineNo := base.Pos
+	ir.CurFunc = nil
+
+	// Set line number equal to the line number where the method is declared.
+	var m *types.Field
+	if lookdot0(meth, rcvrtype, &m, false) == 1 && m.Pos.IsKnown() {
+		base.Pos = m.Pos
+	}
+	// Note: !m.Pos.IsKnown() happens for method expressions where
+	// the method is implicitly declared. The Error method of the
+	// built-in error type is one such method.  We leave the line
+	// number at the use of the method expression in this
+	// case. See issue 29389.
+
+	tfn := ir.NewFuncType(base.Pos, nil,
+		NewFuncParams(t0.Params(), true),
+		NewFuncParams(t0.Results(), false))
+
+	fn := DeclFunc(sym, tfn)
+	fn.SetDupok(true)
+	fn.SetNeedctxt(true)
+
+	// Declare and initialize variable holding receiver.
+	cr := ir.NewClosureRead(rcvrtype, types.Rnd(int64(types.PtrSize), int64(rcvrtype.Align)))
+	ptr := NewName(Lookup(".this"))
+	Declare(ptr, ir.PAUTO)
+	ptr.SetUsed(true)
+	var body []ir.Node
+	if rcvrtype.IsPtr() || rcvrtype.IsInterface() {
+		ptr.SetType(rcvrtype)
+		body = append(body, ir.NewAssignStmt(base.Pos, ptr, cr))
+	} else {
+		ptr.SetType(types.NewPtr(rcvrtype))
+		body = append(body, ir.NewAssignStmt(base.Pos, ptr, NodAddr(cr)))
+	}
+
+	call := ir.NewCallExpr(base.Pos, ir.OCALL, ir.NewSelectorExpr(base.Pos, ir.OXDOT, ptr, meth), nil)
+	call.Args.Set(ir.ParamNames(tfn.Type()))
+	call.IsDDD = tfn.Type().IsVariadic()
+	if t0.NumResults() != 0 {
+		ret := ir.NewReturnStmt(base.Pos, nil)
+		ret.Results = []ir.Node{call}
+		body = append(body, ret)
+	} else {
+		body = append(body, call)
+	}
+
+	fn.Body.Set(body)
+	FinishFuncBody()
+
+	Func(fn)
+	// Need to typecheck the body of the just-generated wrapper.
+	// typecheckslice() requires that Curfn is set when processing an ORETURN.
+	ir.CurFunc = fn
+	Stmts(fn.Body)
+	sym.Def = fn
+	Target.Decls = append(Target.Decls, fn)
+	ir.CurFunc = savecurfn
+	base.Pos = saveLineNo
+
+	return fn
+}
+
+func typecheckpartialcall(n ir.Node, sym *types.Sym) *ir.CallPartExpr {
+	switch n.Op() {
+	case ir.ODOTINTER, ir.ODOTMETH:
+		break
+
+	default:
+		base.Fatalf("invalid typecheckpartialcall")
+	}
+	dot := n.(*ir.SelectorExpr)
+
+	// Create top-level function.
+	fn := makepartialcall(dot, dot.Type(), sym)
+	fn.SetWrapper(true)
+
+	return ir.NewCallPartExpr(dot.Pos(), dot.X, dot.Selection, fn)
+}
diff --git a/src/cmd/compile/internal/gc/iexport.go b/src/cmd/compile/internal/typecheck/iexport.go
similarity index 99%
rename from src/cmd/compile/internal/gc/iexport.go
rename to src/cmd/compile/internal/typecheck/iexport.go
index fd64b69077..4ddee01b5a 100644
--- a/src/cmd/compile/internal/gc/iexport.go
+++ b/src/cmd/compile/internal/typecheck/iexport.go
@@ -199,16 +199,11 @@
 // they're expected to change much more rapidly, so they're omitted
 // here. See exportWriter's varExt/funcExt/etc methods for details.
 
-package gc
+package typecheck
 
 import (
 	"bufio"
 	"bytes"
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/types"
-	"cmd/internal/goobj"
-	"cmd/internal/src"
 	"crypto/md5"
 	"encoding/binary"
 	"fmt"
@@ -217,6 +212,12 @@ import (
 	"math/big"
 	"sort"
 	"strings"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/goobj"
+	"cmd/internal/src"
 )
 
 // Current indexed export format version. Increase with each format change.
@@ -245,7 +246,7 @@ const (
 	interfaceType
 )
 
-func iexport(out *bufio.Writer) {
+func WriteExports(out *bufio.Writer) {
 	p := iexporter{
 		allPkgs:     map[*types.Pkg]bool{},
 		stringIndex: map[string]uint64{},
@@ -455,7 +456,7 @@ func (p *iexporter) doDecl(n *ir.Name) {
 	case ir.OLITERAL:
 		// Constant.
 		// TODO(mdempsky): Do we still need this typecheck? If so, why?
-		n = typecheck(n, ctxExpr).(*ir.Name)
+		n = Expr(n).(*ir.Name)
 		w.tag('C')
 		w.pos(n.Pos())
 		w.value(n.Type(), n.Val())
diff --git a/src/cmd/compile/internal/gc/iimport.go b/src/cmd/compile/internal/typecheck/iimport.go
similarity index 97%
rename from src/cmd/compile/internal/gc/iimport.go
rename to src/cmd/compile/internal/typecheck/iimport.go
index e9dc2a3248..ab43d4f71b 100644
--- a/src/cmd/compile/internal/gc/iimport.go
+++ b/src/cmd/compile/internal/typecheck/iimport.go
@@ -5,16 +5,9 @@
 // Indexed package import.
 // See iexport.go for the export data format.
 
-package gc
+package typecheck
 
 import (
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/types"
-	"cmd/internal/bio"
-	"cmd/internal/goobj"
-	"cmd/internal/obj"
-	"cmd/internal/src"
 	"encoding/binary"
 	"fmt"
 	"go/constant"
@@ -22,6 +15,14 @@ import (
 	"math/big"
 	"os"
 	"strings"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/bio"
+	"cmd/internal/goobj"
+	"cmd/internal/obj"
+	"cmd/internal/src"
 )
 
 // An iimporterAndOffset identifies an importer and an offset within
@@ -32,9 +33,9 @@ type iimporterAndOffset struct {
 }
 
 var (
-	// declImporter maps from imported identifiers to an importer
+	// DeclImporter maps from imported identifiers to an importer
 	// and offset where that identifier's declaration can be read.
-	declImporter = map[*types.Sym]iimporterAndOffset{}
+	DeclImporter = map[*types.Sym]iimporterAndOffset{}
 
 	// inlineImporter is like declImporter, but for inline bodies
 	// for function and method symbols.
@@ -51,7 +52,7 @@ func expandDecl(n ir.Node) ir.Node {
 		return n.(*ir.Name)
 	}
 
-	r := importReaderFor(id.Sym(), declImporter)
+	r := importReaderFor(id.Sym(), DeclImporter)
 	if r == nil {
 		// Can happen if user tries to reference an undeclared name.
 		return n
@@ -60,7 +61,7 @@ func expandDecl(n ir.Node) ir.Node {
 	return r.doDecl(n.Sym())
 }
 
-func expandInline(fn *ir.Func) {
+func ImportBody(fn *ir.Func) {
 	if fn.Inl.Body != nil {
 		return
 	}
@@ -105,7 +106,7 @@ func (r *intReader) uint64() uint64 {
 	return i
 }
 
-func iimport(pkg *types.Pkg, in *bio.Reader) (fingerprint goobj.FingerprintType) {
+func ReadImports(pkg *types.Pkg, in *bio.Reader) (fingerprint goobj.FingerprintType) {
 	ird := &intReader{in, pkg}
 
 	version := ird.uint64()
@@ -170,8 +171,8 @@ func iimport(pkg *types.Pkg, in *bio.Reader) (fingerprint goobj.FingerprintType)
 			s := pkg.Lookup(p.stringAt(ird.uint64()))
 			off := ird.uint64()
 
-			if _, ok := declImporter[s]; !ok {
-				declImporter[s] = iimporterAndOffset{p, off}
+			if _, ok := DeclImporter[s]; !ok {
+				DeclImporter[s] = iimporterAndOffset{p, off}
 			}
 		}
 	}
@@ -705,9 +706,9 @@ func (r *importReader) doInline(fn *ir.Func) {
 		base.Fatalf("%v already has inline body", fn)
 	}
 
-	funchdr(fn)
+	StartFuncBody(fn)
 	body := r.stmtList()
-	funcbody()
+	FinishFuncBody()
 	if body == nil {
 		//
 		// Make sure empty body is not interpreted as
@@ -778,7 +779,7 @@ func (r *importReader) caseList(sw ir.Node) []ir.Node {
 			// names after import. That's okay: swt.go only needs
 			// Sym for diagnostics anyway.
 			caseVar := ir.NewNameAt(cas.Pos(), r.ident())
-			declare(caseVar, dclcontext)
+			Declare(caseVar, DeclContext)
 			cas.Vars = []ir.Node{caseVar}
 			caseVar.Defn = sw.(*ir.SwitchStmt).Tag
 		}
@@ -820,7 +821,7 @@ func (r *importReader) node() ir.Node {
 		pos := r.pos()
 		typ := r.typ()
 
-		n := npos(pos, nodnil())
+		n := npos(pos, NodNil())
 		n.SetType(typ)
 		return n
 
@@ -959,7 +960,7 @@ func (r *importReader) node() ir.Node {
 		return ir.NewUnaryExpr(r.pos(), op, r.expr())
 
 	case ir.OADDR:
-		return nodAddrAt(r.pos(), r.expr())
+		return NodAddrAt(r.pos(), r.expr())
 
 	case ir.ODEREF:
 		return ir.NewStarExpr(r.pos(), r.expr())
@@ -991,7 +992,7 @@ func (r *importReader) node() ir.Node {
 		lhs := ir.NewDeclNameAt(pos, ir.ONAME, r.ident())
 		lhs.SetType(r.typ())
 
-		declare(lhs, ir.PAUTO)
+		Declare(lhs, ir.PAUTO)
 
 		var stmts ir.Nodes
 		stmts.Append(ir.NewDecl(base.Pos, ir.ODCL, lhs))
@@ -1089,12 +1090,12 @@ func (r *importReader) node() ir.Node {
 		var sym *types.Sym
 		pos := r.pos()
 		if label := r.string(); label != "" {
-			sym = lookup(label)
+			sym = Lookup(label)
 		}
 		return ir.NewBranchStmt(pos, op, sym)
 
 	case ir.OLABEL:
-		return ir.NewLabelStmt(r.pos(), lookup(r.string()))
+		return ir.NewLabelStmt(r.pos(), Lookup(r.string()))
 
 	case ir.OEND:
 		return nil
diff --git a/src/cmd/compile/internal/gc/mapfile_mmap.go b/src/cmd/compile/internal/typecheck/mapfile_mmap.go
similarity index 98%
rename from src/cmd/compile/internal/gc/mapfile_mmap.go
rename to src/cmd/compile/internal/typecheck/mapfile_mmap.go
index 9483688d68..2f3aa16dec 100644
--- a/src/cmd/compile/internal/gc/mapfile_mmap.go
+++ b/src/cmd/compile/internal/typecheck/mapfile_mmap.go
@@ -4,7 +4,7 @@
 
 // +build darwin dragonfly freebsd linux netbsd openbsd
 
-package gc
+package typecheck
 
 import (
 	"os"
diff --git a/src/cmd/compile/internal/gc/mapfile_read.go b/src/cmd/compile/internal/typecheck/mapfile_read.go
similarity index 96%
rename from src/cmd/compile/internal/gc/mapfile_read.go
rename to src/cmd/compile/internal/typecheck/mapfile_read.go
index c6f68ed5df..4059f261d4 100644
--- a/src/cmd/compile/internal/gc/mapfile_read.go
+++ b/src/cmd/compile/internal/typecheck/mapfile_read.go
@@ -4,7 +4,7 @@
 
 // +build !darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd
 
-package gc
+package typecheck
 
 import (
 	"io"
diff --git a/src/cmd/compile/internal/gc/mkbuiltin.go b/src/cmd/compile/internal/typecheck/mkbuiltin.go
similarity index 99%
rename from src/cmd/compile/internal/gc/mkbuiltin.go
rename to src/cmd/compile/internal/typecheck/mkbuiltin.go
index 38aa601645..2a208d960f 100644
--- a/src/cmd/compile/internal/gc/mkbuiltin.go
+++ b/src/cmd/compile/internal/typecheck/mkbuiltin.go
@@ -33,7 +33,7 @@ func main() {
 	var b bytes.Buffer
 	fmt.Fprintln(&b, "// Code generated by mkbuiltin.go. DO NOT EDIT.")
 	fmt.Fprintln(&b)
-	fmt.Fprintln(&b, "package gc")
+	fmt.Fprintln(&b, "package typecheck")
 	fmt.Fprintln(&b)
 	fmt.Fprintln(&b, `import (`)
 	fmt.Fprintln(&b, `      "cmd/compile/internal/ir"`)
diff --git a/src/cmd/compile/internal/typecheck/stmt.go b/src/cmd/compile/internal/typecheck/stmt.go
new file mode 100644
index 0000000000..889ee06d6e
--- /dev/null
+++ b/src/cmd/compile/internal/typecheck/stmt.go
@@ -0,0 +1,435 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typecheck
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
+)
+
+// range
+func typecheckrange(n *ir.RangeStmt) {
+	// Typechecking order is important here:
+	// 0. first typecheck range expression (slice/map/chan),
+	//	it is evaluated only once and so logically it is not part of the loop.
+	// 1. typecheck produced values,
+	//	this part can declare new vars and so it must be typechecked before body,
+	//	because body can contain a closure that captures the vars.
+	// 2. decldepth++ to denote loop body.
+	// 3. typecheck body.
+	// 4. decldepth--.
+	typecheckrangeExpr(n)
+
+	// second half of dance, the first half being typecheckrangeExpr
+	n.SetTypecheck(1)
+	ls := n.Vars
+	for i1, n1 := range ls {
+		if n1.Typecheck() == 0 {
+			ls[i1] = AssignExpr(ls[i1])
+		}
+	}
+
+	decldepth++
+	Stmts(n.Body)
+	decldepth--
+}
+
+func typecheckrangeExpr(n *ir.RangeStmt) {
+	n.X = Expr(n.X)
+
+	t := n.X.Type()
+	if t == nil {
+		return
+	}
+	// delicate little dance.  see typecheckas2
+	ls := n.Vars
+	for i1, n1 := range ls {
+		if !ir.DeclaredBy(n1, n) {
+			ls[i1] = AssignExpr(ls[i1])
+		}
+	}
+
+	if t.IsPtr() && t.Elem().IsArray() {
+		t = t.Elem()
+	}
+	n.SetType(t)
+
+	var t1, t2 *types.Type
+	toomany := false
+	switch t.Kind() {
+	default:
+		base.ErrorfAt(n.Pos(), "cannot range over %L", n.X)
+		return
+
+	case types.TARRAY, types.TSLICE:
+		t1 = types.Types[types.TINT]
+		t2 = t.Elem()
+
+	case types.TMAP:
+		t1 = t.Key()
+		t2 = t.Elem()
+
+	case types.TCHAN:
+		if !t.ChanDir().CanRecv() {
+			base.ErrorfAt(n.Pos(), "invalid operation: range %v (receive from send-only type %v)", n.X, n.X.Type())
+			return
+		}
+
+		t1 = t.Elem()
+		t2 = nil
+		if len(n.Vars) == 2 {
+			toomany = true
+		}
+
+	case types.TSTRING:
+		t1 = types.Types[types.TINT]
+		t2 = types.RuneType
+	}
+
+	if len(n.Vars) > 2 || toomany {
+		base.ErrorfAt(n.Pos(), "too many variables in range")
+	}
+
+	var v1, v2 ir.Node
+	if len(n.Vars) != 0 {
+		v1 = n.Vars[0]
+	}
+	if len(n.Vars) > 1 {
+		v2 = n.Vars[1]
+	}
+
+	// this is not only an optimization but also a requirement in the spec.
+	// "if the second iteration variable is the blank identifier, the range
+	// clause is equivalent to the same clause with only the first variable
+	// present."
+	if ir.IsBlank(v2) {
+		if v1 != nil {
+			n.Vars = []ir.Node{v1}
+		}
+		v2 = nil
+	}
+
+	if v1 != nil {
+		if ir.DeclaredBy(v1, n) {
+			v1.SetType(t1)
+		} else if v1.Type() != nil {
+			if op, why := assignop(t1, v1.Type()); op == ir.OXXX {
+				base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t1, v1, why)
+			}
+		}
+		checkassign(n, v1)
+	}
+
+	if v2 != nil {
+		if ir.DeclaredBy(v2, n) {
+			v2.SetType(t2)
+		} else if v2.Type() != nil {
+			if op, why := assignop(t2, v2.Type()); op == ir.OXXX {
+				base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t2, v2, why)
+			}
+		}
+		checkassign(n, v2)
+	}
+}
+
+// select
+func typecheckselect(sel *ir.SelectStmt) {
+	var def ir.Node
+	lno := ir.SetPos(sel)
+	Stmts(sel.Init())
+	for _, ncase := range sel.Cases {
+		ncase := ncase.(*ir.CaseStmt)
+
+		if len(ncase.List) == 0 {
+			// default
+			if def != nil {
+				base.ErrorfAt(ncase.Pos(), "multiple defaults in select (first at %v)", ir.Line(def))
+			} else {
+				def = ncase
+			}
+		} else if len(ncase.List) > 1 {
+			base.ErrorfAt(ncase.Pos(), "select cases cannot be lists")
+		} else {
+			ncase.List[0] = Stmt(ncase.List[0])
+			n := ncase.List[0]
+			ncase.Comm = n
+			ncase.List.Set(nil)
+			oselrecv2 := func(dst, recv ir.Node, colas bool) {
+				n := ir.NewAssignListStmt(n.Pos(), ir.OSELRECV2, nil, nil)
+				n.Lhs = []ir.Node{dst, ir.BlankNode}
+				n.Rhs = []ir.Node{recv}
+				n.Def = colas
+				n.SetTypecheck(1)
+				ncase.Comm = n
+			}
+			switch n.Op() {
+			default:
+				pos := n.Pos()
+				if n.Op() == ir.ONAME {
+					// We don't have the right position for ONAME nodes (see #15459 and
+					// others). Using ncase.Pos for now as it will provide the correct
+					// line number (assuming the expression follows the "case" keyword
+					// on the same line). This matches the approach before 1.10.
+					pos = ncase.Pos()
+				}
+				base.ErrorfAt(pos, "select case must be receive, send or assign recv")
+
+			case ir.OAS:
+				// convert x = <-c into x, _ = <-c
+				// remove implicit conversions; the eventual assignment
+				// will reintroduce them.
+				n := n.(*ir.AssignStmt)
+				if r := n.Y; r.Op() == ir.OCONVNOP || r.Op() == ir.OCONVIFACE {
+					r := r.(*ir.ConvExpr)
+					if r.Implicit() {
+						n.Y = r.X
+					}
+				}
+				if n.Y.Op() != ir.ORECV {
+					base.ErrorfAt(n.Pos(), "select assignment must have receive on right hand side")
+					break
+				}
+				oselrecv2(n.X, n.Y, n.Def)
+
+			case ir.OAS2RECV:
+				n := n.(*ir.AssignListStmt)
+				if n.Rhs[0].Op() != ir.ORECV {
+					base.ErrorfAt(n.Pos(), "select assignment must have receive on right hand side")
+					break
+				}
+				n.SetOp(ir.OSELRECV2)
+
+			case ir.ORECV:
+				// convert <-c into _, _ = <-c
+				n := n.(*ir.UnaryExpr)
+				oselrecv2(ir.BlankNode, n, false)
+
+			case ir.OSEND:
+				break
+			}
+		}
+
+		Stmts(ncase.Body)
+	}
+
+	base.Pos = lno
+}
+
+type typeSet struct {
+	m map[string][]typeSetEntry
+}
+
+func (s *typeSet) add(pos src.XPos, typ *types.Type) {
+	if s.m == nil {
+		s.m = make(map[string][]typeSetEntry)
+	}
+
+	// LongString does not uniquely identify types, so we need to
+	// disambiguate collisions with types.Identical.
+	// TODO(mdempsky): Add a method that *is* unique.
+	ls := typ.LongString()
+	prevs := s.m[ls]
+	for _, prev := range prevs {
+		if types.Identical(typ, prev.typ) {
+			base.ErrorfAt(pos, "duplicate case %v in type switch\n\tprevious case at %s", typ, base.FmtPos(prev.pos))
+			return
+		}
+	}
+	s.m[ls] = append(prevs, typeSetEntry{pos, typ})
+}
+
+type typeSetEntry struct {
+	pos src.XPos
+	typ *types.Type
+}
+
+func typecheckExprSwitch(n *ir.SwitchStmt) {
+	t := types.Types[types.TBOOL]
+	if n.Tag != nil {
+		n.Tag = Expr(n.Tag)
+		n.Tag = DefaultLit(n.Tag, nil)
+		t = n.Tag.Type()
+	}
+
+	var nilonly string
+	if t != nil {
+		switch {
+		case t.IsMap():
+			nilonly = "map"
+		case t.Kind() == types.TFUNC:
+			nilonly = "func"
+		case t.IsSlice():
+			nilonly = "slice"
+
+		case !types.IsComparable(t):
+			if t.IsStruct() {
+				base.ErrorfAt(n.Pos(), "cannot switch on %L (struct containing %v cannot be compared)", n.Tag, types.IncomparableField(t).Type)
+			} else {
+				base.ErrorfAt(n.Pos(), "cannot switch on %L", n.Tag)
+			}
+			t = nil
+		}
+	}
+
+	var defCase ir.Node
+	var cs constSet
+	for _, ncase := range n.Cases {
+		ncase := ncase.(*ir.CaseStmt)
+		ls := ncase.List
+		if len(ls) == 0 { // default:
+			if defCase != nil {
+				base.ErrorfAt(ncase.Pos(), "multiple defaults in switch (first at %v)", ir.Line(defCase))
+			} else {
+				defCase = ncase
+			}
+		}
+
+		for i := range ls {
+			ir.SetPos(ncase)
+			ls[i] = Expr(ls[i])
+			ls[i] = DefaultLit(ls[i], t)
+			n1 := ls[i]
+			if t == nil || n1.Type() == nil {
+				continue
+			}
+
+			if nilonly != "" && !ir.IsNil(n1) {
+				base.ErrorfAt(ncase.Pos(), "invalid case %v in switch (can only compare %s %v to nil)", n1, nilonly, n.Tag)
+			} else if t.IsInterface() && !n1.Type().IsInterface() && !types.IsComparable(n1.Type()) {
+				base.ErrorfAt(ncase.Pos(), "invalid case %L in switch (incomparable type)", n1)
+			} else {
+				op1, _ := assignop(n1.Type(), t)
+				op2, _ := assignop(t, n1.Type())
+				if op1 == ir.OXXX && op2 == ir.OXXX {
+					if n.Tag != nil {
+						base.ErrorfAt(ncase.Pos(), "invalid case %v in switch on %v (mismatched types %v and %v)", n1, n.Tag, n1.Type(), t)
+					} else {
+						base.ErrorfAt(ncase.Pos(), "invalid case %v in switch (mismatched types %v and bool)", n1, n1.Type())
+					}
+				}
+			}
+
+			// Don't check for duplicate bools. Although the spec allows it,
+			// (1) the compiler hasn't checked it in the past, so compatibility mandates it, and
+			// (2) it would disallow useful things like
+			//       case GOARCH == "arm" && GOARM == "5":
+			//       case GOARCH == "arm":
+			//     which would both evaluate to false for non-ARM compiles.
+			if !n1.Type().IsBoolean() {
+				cs.add(ncase.Pos(), n1, "case", "switch")
+			}
+		}
+
+		Stmts(ncase.Body)
+	}
+}
+
+func typecheckTypeSwitch(n *ir.SwitchStmt) {
+	guard := n.Tag.(*ir.TypeSwitchGuard)
+	guard.X = Expr(guard.X)
+	t := guard.X.Type()
+	if t != nil && !t.IsInterface() {
+		base.ErrorfAt(n.Pos(), "cannot type switch on non-interface value %L", guard.X)
+		t = nil
+	}
+
+	// We don't actually declare the type switch's guarded
+	// declaration itself. So if there are no cases, we won't
+	// notice that it went unused.
+	if v := guard.Tag; v != nil && !ir.IsBlank(v) && len(n.Cases) == 0 {
+		base.ErrorfAt(v.Pos(), "%v declared but not used", v.Sym())
+	}
+
+	var defCase, nilCase ir.Node
+	var ts typeSet
+	for _, ncase := range n.Cases {
+		ncase := ncase.(*ir.CaseStmt)
+		ls := ncase.List
+		if len(ls) == 0 { // default:
+			if defCase != nil {
+				base.ErrorfAt(ncase.Pos(), "multiple defaults in switch (first at %v)", ir.Line(defCase))
+			} else {
+				defCase = ncase
+			}
+		}
+
+		for i := range ls {
+			ls[i] = check(ls[i], ctxExpr|ctxType)
+			n1 := ls[i]
+			if t == nil || n1.Type() == nil {
+				continue
+			}
+
+			var missing, have *types.Field
+			var ptr int
+			if ir.IsNil(n1) { // case nil:
+				if nilCase != nil {
+					base.ErrorfAt(ncase.Pos(), "multiple nil cases in type switch (first at %v)", ir.Line(nilCase))
+				} else {
+					nilCase = ncase
+				}
+				continue
+			}
+			if n1.Op() != ir.OTYPE {
+				base.ErrorfAt(ncase.Pos(), "%L is not a type", n1)
+				continue
+			}
+			if !n1.Type().IsInterface() && !implements(n1.Type(), t, &missing, &have, &ptr) && !missing.Broke() {
+				if have != nil && !have.Broke() {
+					base.ErrorfAt(ncase.Pos(), "impossible type switch case: %L cannot have dynamic type %v"+
+						" (wrong type for %v method)\n\thave %v%S\n\twant %v%S", guard.X, n1.Type(), missing.Sym, have.Sym, have.Type, missing.Sym, missing.Type)
+				} else if ptr != 0 {
+					base.ErrorfAt(ncase.Pos(), "impossible type switch case: %L cannot have dynamic type %v"+
+						" (%v method has pointer receiver)", guard.X, n1.Type(), missing.Sym)
+				} else {
+					base.ErrorfAt(ncase.Pos(), "impossible type switch case: %L cannot have dynamic type %v"+
+						" (missing %v method)", guard.X, n1.Type(), missing.Sym)
+				}
+				continue
+			}
+
+			ts.add(ncase.Pos(), n1.Type())
+		}
+
+		if len(ncase.Vars) != 0 {
+			// Assign the clause variable's type.
+			vt := t
+			if len(ls) == 1 {
+				if ls[0].Op() == ir.OTYPE {
+					vt = ls[0].Type()
+				} else if !ir.IsNil(ls[0]) {
+					// Invalid single-type case;
+					// mark variable as broken.
+					vt = nil
+				}
+			}
+
+			nvar := ncase.Vars[0]
+			nvar.SetType(vt)
+			if vt != nil {
+				nvar = AssignExpr(nvar)
+			} else {
+				// Clause variable is broken; prevent typechecking.
+				nvar.SetTypecheck(1)
+				nvar.SetWalkdef(1)
+			}
+			ncase.Vars[0] = nvar
+		}
+
+		Stmts(ncase.Body)
+	}
+}
+
+// typecheckswitch typechecks a switch statement.
+func typecheckswitch(n *ir.SwitchStmt) {
+	Stmts(n.Init())
+	if n.Tag != nil && n.Tag.Op() == ir.OTYPESW {
+		typecheckTypeSwitch(n)
+	} else {
+		typecheckExprSwitch(n)
+	}
+}
diff --git a/src/cmd/compile/internal/typecheck/subr.go b/src/cmd/compile/internal/typecheck/subr.go
new file mode 100644
index 0000000000..22ebf2a4b3
--- /dev/null
+++ b/src/cmd/compile/internal/typecheck/subr.go
@@ -0,0 +1,793 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typecheck
+
+import (
+	"fmt"
+	"sort"
+	"strconv"
+	"strings"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
+)
+
+func AssignConv(n ir.Node, t *types.Type, context string) ir.Node {
+	return assignconvfn(n, t, func() string { return context })
+}
+
+// DotImportRefs maps idents introduced by importDot back to the
+// ir.PkgName they were dot-imported through.
+var DotImportRefs map[*ir.Ident]*ir.PkgName
+
+// LookupNum looks up the symbol starting with prefix and ending with
+// the decimal n. If prefix is too long, LookupNum panics.
+func LookupNum(prefix string, n int) *types.Sym {
+	var buf [20]byte // plenty long enough for all current users
+	copy(buf[:], prefix)
+	b := strconv.AppendInt(buf[:len(prefix)], int64(n), 10)
+	return types.LocalPkg.LookupBytes(b)
+}
+
+// Given funarg struct list, return list of fn args.
+func NewFuncParams(tl *types.Type, mustname bool) []*ir.Field {
+	var args []*ir.Field
+	gen := 0
+	for _, t := range tl.Fields().Slice() {
+		s := t.Sym
+		if mustname && (s == nil || s.Name == "_") {
+			// invent a name so that we can refer to it in the trampoline
+			s = LookupNum(".anon", gen)
+			gen++
+		}
+		a := ir.NewField(base.Pos, s, nil, t.Type)
+		a.Pos = t.Pos
+		a.IsDDD = t.IsDDD()
+		args = append(args, a)
+	}
+
+	return args
+}
+
+// newname returns a new ONAME Node associated with symbol s.
+func NewName(s *types.Sym) *ir.Name {
+	n := ir.NewNameAt(base.Pos, s)
+	n.Curfn = ir.CurFunc
+	return n
+}
+
+// NodAddr returns a node representing &n at base.Pos.
+func NodAddr(n ir.Node) *ir.AddrExpr {
+	return NodAddrAt(base.Pos, n)
+}
+
+// nodAddrPos returns a node representing &n at position pos.
+func NodAddrAt(pos src.XPos, n ir.Node) *ir.AddrExpr {
+	return ir.NewAddrExpr(pos, n)
+}
+
+func NodNil() ir.Node {
+	n := ir.NewNilExpr(base.Pos)
+	n.SetType(types.Types[types.TNIL])
+	return n
+}
+
+// in T.field
+// find missing fields that
+// will give shortest unique addressing.
+// modify the tree with missing type names.
+func AddImplicitDots(n *ir.SelectorExpr) *ir.SelectorExpr {
+	n.X = check(n.X, ctxType|ctxExpr)
+	if n.X.Diag() {
+		n.SetDiag(true)
+	}
+	t := n.X.Type()
+	if t == nil {
+		return n
+	}
+
+	if n.X.Op() == ir.OTYPE {
+		return n
+	}
+
+	s := n.Sel
+	if s == nil {
+		return n
+	}
+
+	switch path, ambig := dotpath(s, t, nil, false); {
+	case path != nil:
+		// rebuild elided dots
+		for c := len(path) - 1; c >= 0; c-- {
+			dot := ir.NewSelectorExpr(base.Pos, ir.ODOT, n.X, path[c].field.Sym)
+			dot.SetImplicit(true)
+			dot.SetType(path[c].field.Type)
+			n.X = dot
+		}
+	case ambig:
+		base.Errorf("ambiguous selector %v", n)
+		n.X = nil
+	}
+
+	return n
+}
+
+func CalcMethods(t *types.Type) {
+	if t == nil || t.AllMethods().Len() != 0 {
+		return
+	}
+
+	// mark top-level method symbols
+	// so that expand1 doesn't consider them.
+	for _, f := range t.Methods().Slice() {
+		f.Sym.SetUniq(true)
+	}
+
+	// generate all reachable methods
+	slist = slist[:0]
+	expand1(t, true)
+
+	// check each method to be uniquely reachable
+	var ms []*types.Field
+	for i, sl := range slist {
+		slist[i].field = nil
+		sl.field.Sym.SetUniq(false)
+
+		var f *types.Field
+		path, _ := dotpath(sl.field.Sym, t, &f, false)
+		if path == nil {
+			continue
+		}
+
+		// dotpath may have dug out arbitrary fields, we only want methods.
+		if !f.IsMethod() {
+			continue
+		}
+
+		// add it to the base type method list
+		f = f.Copy()
+		f.Embedded = 1 // needs a trampoline
+		for _, d := range path {
+			if d.field.Type.IsPtr() {
+				f.Embedded = 2
+				break
+			}
+		}
+		ms = append(ms, f)
+	}
+
+	for _, f := range t.Methods().Slice() {
+		f.Sym.SetUniq(false)
+	}
+
+	ms = append(ms, t.Methods().Slice()...)
+	sort.Sort(types.MethodsByName(ms))
+	t.AllMethods().Set(ms)
+}
+
+// adddot1 returns the number of fields or methods named s at depth d in Type t.
+// If exactly one exists, it will be returned in *save (if save is not nil),
+// and dotlist will contain the path of embedded fields traversed to find it,
+// in reverse order. If none exist, more will indicate whether t contains any
+// embedded fields at depth d, so callers can decide whether to retry at
+// a greater depth.
+func adddot1(s *types.Sym, t *types.Type, d int, save **types.Field, ignorecase bool) (c int, more bool) {
+	if t.Recur() {
+		return
+	}
+	t.SetRecur(true)
+	defer t.SetRecur(false)
+
+	var u *types.Type
+	d--
+	if d < 0 {
+		// We've reached our target depth. If t has any fields/methods
+		// named s, then we're done. Otherwise, we still need to check
+		// below for embedded fields.
+		c = lookdot0(s, t, save, ignorecase)
+		if c != 0 {
+			return c, false
+		}
+	}
+
+	u = t
+	if u.IsPtr() {
+		u = u.Elem()
+	}
+	if !u.IsStruct() && !u.IsInterface() {
+		return c, false
+	}
+
+	for _, f := range u.Fields().Slice() {
+		if f.Embedded == 0 || f.Sym == nil {
+			continue
+		}
+		if d < 0 {
+			// Found an embedded field at target depth.
+			return c, true
+		}
+		a, more1 := adddot1(s, f.Type, d, save, ignorecase)
+		if a != 0 && c == 0 {
+			dotlist[d].field = f
+		}
+		c += a
+		if more1 {
+			more = true
+		}
+	}
+
+	return c, more
+}
+
+// dotlist is used by adddot1 to record the path of embedded fields
+// used to access a target field or method.
+// Must be non-nil so that dotpath returns a non-nil slice even if d is zero.
+var dotlist = make([]dlist, 10)
+
+// Convert node n for assignment to type t.
+func assignconvfn(n ir.Node, t *types.Type, context func() string) ir.Node {
+	if n == nil || n.Type() == nil || n.Type().Broke() {
+		return n
+	}
+
+	if t.Kind() == types.TBLANK && n.Type().Kind() == types.TNIL {
+		base.Errorf("use of untyped nil")
+	}
+
+	n = convlit1(n, t, false, context)
+	if n.Type() == nil {
+		return n
+	}
+	if t.Kind() == types.TBLANK {
+		return n
+	}
+
+	// Convert ideal bool from comparison to plain bool
+	// if the next step is non-bool (like interface{}).
+	if n.Type() == types.UntypedBool && !t.IsBoolean() {
+		if n.Op() == ir.ONAME || n.Op() == ir.OLITERAL {
+			r := ir.NewConvExpr(base.Pos, ir.OCONVNOP, nil, n)
+			r.SetType(types.Types[types.TBOOL])
+			r.SetTypecheck(1)
+			r.SetImplicit(true)
+			n = r
+		}
+	}
+
+	if types.Identical(n.Type(), t) {
+		return n
+	}
+
+	op, why := assignop(n.Type(), t)
+	if op == ir.OXXX {
+		base.Errorf("cannot use %L as type %v in %s%s", n, t, context(), why)
+		op = ir.OCONV
+	}
+
+	r := ir.NewConvExpr(base.Pos, op, t, n)
+	r.SetTypecheck(1)
+	r.SetImplicit(true)
+	return r
+}
+
+// Is type src assignment compatible to type dst?
+// If so, return op code to use in conversion.
+// If not, return OXXX. In this case, the string return parameter may
+// hold a reason why. In all other cases, it'll be the empty string.
+func assignop(src, dst *types.Type) (ir.Op, string) {
+	if src == dst {
+		return ir.OCONVNOP, ""
+	}
+	if src == nil || dst == nil || src.Kind() == types.TFORW || dst.Kind() == types.TFORW || src.Underlying() == nil || dst.Underlying() == nil {
+		return ir.OXXX, ""
+	}
+
+	// 1. src type is identical to dst.
+	if types.Identical(src, dst) {
+		return ir.OCONVNOP, ""
+	}
+
+	// 2. src and dst have identical underlying types
+	// and either src or dst is not a named type or
+	// both are empty interface types.
+	// For assignable but different non-empty interface types,
+	// we want to recompute the itab. Recomputing the itab ensures
+	// that itabs are unique (thus an interface with a compile-time
+	// type I has an itab with interface type I).
+	if types.Identical(src.Underlying(), dst.Underlying()) {
+		if src.IsEmptyInterface() {
+			// Conversion between two empty interfaces
+			// requires no code.
+			return ir.OCONVNOP, ""
+		}
+		if (src.Sym() == nil || dst.Sym() == nil) && !src.IsInterface() {
+			// Conversion between two types, at least one unnamed,
+			// needs no conversion. The exception is nonempty interfaces
+			// which need to have their itab updated.
+			return ir.OCONVNOP, ""
+		}
+	}
+
+	// 3. dst is an interface type and src implements dst.
+	if dst.IsInterface() && src.Kind() != types.TNIL {
+		var missing, have *types.Field
+		var ptr int
+		if implements(src, dst, &missing, &have, &ptr) {
+			// Call itabname so that (src, dst)
+			// gets added to itabs early, which allows
+			// us to de-virtualize calls through this
+			// type/interface pair later. See peekitabs in reflect.go
+			if types.IsDirectIface(src) && !dst.IsEmptyInterface() {
+				NeedITab(src, dst)
+			}
+
+			return ir.OCONVIFACE, ""
+		}
+
+		// we'll have complained about this method anyway, suppress spurious messages.
+		if have != nil && have.Sym == missing.Sym && (have.Type.Broke() || missing.Type.Broke()) {
+			return ir.OCONVIFACE, ""
+		}
+
+		var why string
+		if isptrto(src, types.TINTER) {
+			why = fmt.Sprintf(":\n\t%v is pointer to interface, not interface", src)
+		} else if have != nil && have.Sym == missing.Sym && have.Nointerface() {
+			why = fmt.Sprintf(":\n\t%v does not implement %v (%v method is marked 'nointerface')", src, dst, missing.Sym)
+		} else if have != nil && have.Sym == missing.Sym {
+			why = fmt.Sprintf(":\n\t%v does not implement %v (wrong type for %v method)\n"+
+				"\t\thave %v%S\n\t\twant %v%S", src, dst, missing.Sym, have.Sym, have.Type, missing.Sym, missing.Type)
+		} else if ptr != 0 {
+			why = fmt.Sprintf(":\n\t%v does not implement %v (%v method has pointer receiver)", src, dst, missing.Sym)
+		} else if have != nil {
+			why = fmt.Sprintf(":\n\t%v does not implement %v (missing %v method)\n"+
+				"\t\thave %v%S\n\t\twant %v%S", src, dst, missing.Sym, have.Sym, have.Type, missing.Sym, missing.Type)
+		} else {
+			why = fmt.Sprintf(":\n\t%v does not implement %v (missing %v method)", src, dst, missing.Sym)
+		}
+
+		return ir.OXXX, why
+	}
+
+	if isptrto(dst, types.TINTER) {
+		why := fmt.Sprintf(":\n\t%v is pointer to interface, not interface", dst)
+		return ir.OXXX, why
+	}
+
+	if src.IsInterface() && dst.Kind() != types.TBLANK {
+		var missing, have *types.Field
+		var ptr int
+		var why string
+		if implements(dst, src, &missing, &have, &ptr) {
+			why = ": need type assertion"
+		}
+		return ir.OXXX, why
+	}
+
+	// 4. src is a bidirectional channel value, dst is a channel type,
+	// src and dst have identical element types, and
+	// either src or dst is not a named type.
+	if src.IsChan() && src.ChanDir() == types.Cboth && dst.IsChan() {
+		if types.Identical(src.Elem(), dst.Elem()) && (src.Sym() == nil || dst.Sym() == nil) {
+			return ir.OCONVNOP, ""
+		}
+	}
+
+	// 5. src is the predeclared identifier nil and dst is a nillable type.
+	if src.Kind() == types.TNIL {
+		switch dst.Kind() {
+		case types.TPTR,
+			types.TFUNC,
+			types.TMAP,
+			types.TCHAN,
+			types.TINTER,
+			types.TSLICE:
+			return ir.OCONVNOP, ""
+		}
+	}
+
+	// 6. rule about untyped constants - already converted by defaultlit.
+
+	// 7. Any typed value can be assigned to the blank identifier.
+	if dst.Kind() == types.TBLANK {
+		return ir.OCONVNOP, ""
+	}
+
+	return ir.OXXX, ""
+}
+
+// Can we convert a value of type src to a value of type dst?
+// If so, return op code to use in conversion (maybe OCONVNOP).
+// If not, return OXXX. In this case, the string return parameter may
+// hold a reason why. In all other cases, it'll be the empty string.
+// srcConstant indicates whether the value of type src is a constant.
+func convertop(srcConstant bool, src, dst *types.Type) (ir.Op, string) {
+	if src == dst {
+		return ir.OCONVNOP, ""
+	}
+	if src == nil || dst == nil {
+		return ir.OXXX, ""
+	}
+
+	// Conversions from regular to go:notinheap are not allowed
+	// (unless it's unsafe.Pointer). These are runtime-specific
+	// rules.
+	// (a) Disallow (*T) to (*U) where T is go:notinheap but U isn't.
+	if src.IsPtr() && dst.IsPtr() && dst.Elem().NotInHeap() && !src.Elem().NotInHeap() {
+		why := fmt.Sprintf(":\n\t%v is incomplete (or unallocatable), but %v is not", dst.Elem(), src.Elem())
+		return ir.OXXX, why
+	}
+	// (b) Disallow string to []T where T is go:notinheap.
+	if src.IsString() && dst.IsSlice() && dst.Elem().NotInHeap() && (dst.Elem().Kind() == types.ByteType.Kind() || dst.Elem().Kind() == types.RuneType.Kind()) {
+		why := fmt.Sprintf(":\n\t%v is incomplete (or unallocatable)", dst.Elem())
+		return ir.OXXX, why
+	}
+
+	// 1. src can be assigned to dst.
+	op, why := assignop(src, dst)
+	if op != ir.OXXX {
+		return op, why
+	}
+
+	// The rules for interfaces are no different in conversions
+	// than assignments. If interfaces are involved, stop now
+	// with the good message from assignop.
+	// Otherwise clear the error.
+	if src.IsInterface() || dst.IsInterface() {
+		return ir.OXXX, why
+	}
+
+	// 2. Ignoring struct tags, src and dst have identical underlying types.
+	if types.IdenticalIgnoreTags(src.Underlying(), dst.Underlying()) {
+		return ir.OCONVNOP, ""
+	}
+
+	// 3. src and dst are unnamed pointer types and, ignoring struct tags,
+	// their base types have identical underlying types.
+	if src.IsPtr() && dst.IsPtr() && src.Sym() == nil && dst.Sym() == nil {
+		if types.IdenticalIgnoreTags(src.Elem().Underlying(), dst.Elem().Underlying()) {
+			return ir.OCONVNOP, ""
+		}
+	}
+
+	// 4. src and dst are both integer or floating point types.
+	if (src.IsInteger() || src.IsFloat()) && (dst.IsInteger() || dst.IsFloat()) {
+		if types.SimType[src.Kind()] == types.SimType[dst.Kind()] {
+			return ir.OCONVNOP, ""
+		}
+		return ir.OCONV, ""
+	}
+
+	// 5. src and dst are both complex types.
+	if src.IsComplex() && dst.IsComplex() {
+		if types.SimType[src.Kind()] == types.SimType[dst.Kind()] {
+			return ir.OCONVNOP, ""
+		}
+		return ir.OCONV, ""
+	}
+
+	// Special case for constant conversions: any numeric
+	// conversion is potentially okay. We'll validate further
+	// within evconst. See #38117.
+	if srcConstant && (src.IsInteger() || src.IsFloat() || src.IsComplex()) && (dst.IsInteger() || dst.IsFloat() || dst.IsComplex()) {
+		return ir.OCONV, ""
+	}
+
+	// 6. src is an integer or has type []byte or []rune
+	// and dst is a string type.
+	if src.IsInteger() && dst.IsString() {
+		return ir.ORUNESTR, ""
+	}
+
+	if src.IsSlice() && dst.IsString() {
+		if src.Elem().Kind() == types.ByteType.Kind() {
+			return ir.OBYTES2STR, ""
+		}
+		if src.Elem().Kind() == types.RuneType.Kind() {
+			return ir.ORUNES2STR, ""
+		}
+	}
+
+	// 7. src is a string and dst is []byte or []rune.
+	// String to slice.
+	if src.IsString() && dst.IsSlice() {
+		if dst.Elem().Kind() == types.ByteType.Kind() {
+			return ir.OSTR2BYTES, ""
+		}
+		if dst.Elem().Kind() == types.RuneType.Kind() {
+			return ir.OSTR2RUNES, ""
+		}
+	}
+
+	// 8. src is a pointer or uintptr and dst is unsafe.Pointer.
+	if (src.IsPtr() || src.IsUintptr()) && dst.IsUnsafePtr() {
+		return ir.OCONVNOP, ""
+	}
+
+	// 9. src is unsafe.Pointer and dst is a pointer or uintptr.
+	if src.IsUnsafePtr() && (dst.IsPtr() || dst.IsUintptr()) {
+		return ir.OCONVNOP, ""
+	}
+
+	// src is map and dst is a pointer to corresponding hmap.
+	// This rule is needed for the implementation detail that
+	// go gc maps are implemented as a pointer to a hmap struct.
+	if src.Kind() == types.TMAP && dst.IsPtr() &&
+		src.MapType().Hmap == dst.Elem() {
+		return ir.OCONVNOP, ""
+	}
+
+	return ir.OXXX, ""
+}
+
+// Code to resolve elided DOTs in embedded types.
+
+// A dlist stores a pointer to a TFIELD Type embedded within
+// a TSTRUCT or TINTER Type.
+type dlist struct {
+	field *types.Field
+}
+
+// dotpath computes the unique shortest explicit selector path to fully qualify
+// a selection expression x.f, where x is of type t and f is the symbol s.
+// If no such path exists, dotpath returns nil.
+// If there are multiple shortest paths to the same depth, ambig is true.
+func dotpath(s *types.Sym, t *types.Type, save **types.Field, ignorecase bool) (path []dlist, ambig bool) {
+	// The embedding of types within structs imposes a tree structure onto
+	// types: structs parent the types they embed, and types parent their
+	// fields or methods. Our goal here is to find the shortest path to
+	// a field or method named s in the subtree rooted at t. To accomplish
+	// that, we iteratively perform depth-first searches of increasing depth
+	// until we either find the named field/method or exhaust the tree.
+	for d := 0; ; d++ {
+		if d > len(dotlist) {
+			dotlist = append(dotlist, dlist{})
+		}
+		if c, more := adddot1(s, t, d, save, ignorecase); c == 1 {
+			return dotlist[:d], false
+		} else if c > 1 {
+			return nil, true
+		} else if !more {
+			return nil, false
+		}
+	}
+}
+
+func expand0(t *types.Type) {
+	u := t
+	if u.IsPtr() {
+		u = u.Elem()
+	}
+
+	if u.IsInterface() {
+		for _, f := range u.Fields().Slice() {
+			if f.Sym.Uniq() {
+				continue
+			}
+			f.Sym.SetUniq(true)
+			slist = append(slist, symlink{field: f})
+		}
+
+		return
+	}
+
+	u = types.ReceiverBaseType(t)
+	if u != nil {
+		for _, f := range u.Methods().Slice() {
+			if f.Sym.Uniq() {
+				continue
+			}
+			f.Sym.SetUniq(true)
+			slist = append(slist, symlink{field: f})
+		}
+	}
+}
+
+func expand1(t *types.Type, top bool) {
+	if t.Recur() {
+		return
+	}
+	t.SetRecur(true)
+
+	if !top {
+		expand0(t)
+	}
+
+	u := t
+	if u.IsPtr() {
+		u = u.Elem()
+	}
+
+	if u.IsStruct() || u.IsInterface() {
+		for _, f := range u.Fields().Slice() {
+			if f.Embedded == 0 {
+				continue
+			}
+			if f.Sym == nil {
+				continue
+			}
+			expand1(f.Type, false)
+		}
+	}
+
+	t.SetRecur(false)
+}
+
+func ifacelookdot(s *types.Sym, t *types.Type, ignorecase bool) (m *types.Field, followptr bool) {
+	if t == nil {
+		return nil, false
+	}
+
+	path, ambig := dotpath(s, t, &m, ignorecase)
+	if path == nil {
+		if ambig {
+			base.Errorf("%v.%v is ambiguous", t, s)
+		}
+		return nil, false
+	}
+
+	for _, d := range path {
+		if d.field.Type.IsPtr() {
+			followptr = true
+			break
+		}
+	}
+
+	if !m.IsMethod() {
+		base.Errorf("%v.%v is a field, not a method", t, s)
+		return nil, followptr
+	}
+
+	return m, followptr
+}
+
+func implements(t, iface *types.Type, m, samename **types.Field, ptr *int) bool {
+	t0 := t
+	if t == nil {
+		return false
+	}
+
+	if t.IsInterface() {
+		i := 0
+		tms := t.Fields().Slice()
+		for _, im := range iface.Fields().Slice() {
+			for i < len(tms) && tms[i].Sym != im.Sym {
+				i++
+			}
+			if i == len(tms) {
+				*m = im
+				*samename = nil
+				*ptr = 0
+				return false
+			}
+			tm := tms[i]
+			if !types.Identical(tm.Type, im.Type) {
+				*m = im
+				*samename = tm
+				*ptr = 0
+				return false
+			}
+		}
+
+		return true
+	}
+
+	t = types.ReceiverBaseType(t)
+	var tms []*types.Field
+	if t != nil {
+		CalcMethods(t)
+		tms = t.AllMethods().Slice()
+	}
+	i := 0
+	for _, im := range iface.Fields().Slice() {
+		if im.Broke() {
+			continue
+		}
+		for i < len(tms) && tms[i].Sym != im.Sym {
+			i++
+		}
+		if i == len(tms) {
+			*m = im
+			*samename, _ = ifacelookdot(im.Sym, t, true)
+			*ptr = 0
+			return false
+		}
+		tm := tms[i]
+		if tm.Nointerface() || !types.Identical(tm.Type, im.Type) {
+			*m = im
+			*samename = tm
+			*ptr = 0
+			return false
+		}
+		followptr := tm.Embedded == 2
+
+		// if pointer receiver in method,
+		// the method does not exist for value types.
+		rcvr := tm.Type.Recv().Type
+		if rcvr.IsPtr() && !t0.IsPtr() && !followptr && !types.IsInterfaceMethod(tm.Type) {
+			if false && base.Flag.LowerR != 0 {
+				base.Errorf("interface pointer mismatch")
+			}
+
+			*m = im
+			*samename = nil
+			*ptr = 1
+			return false
+		}
+	}
+
+	return true
+}
+
+func isptrto(t *types.Type, et types.Kind) bool {
+	if t == nil {
+		return false
+	}
+	if !t.IsPtr() {
+		return false
+	}
+	t = t.Elem()
+	if t == nil {
+		return false
+	}
+	if t.Kind() != et {
+		return false
+	}
+	return true
+}
+
+// lookdot0 returns the number of fields or methods named s associated
+// with Type t. If exactly one exists, it will be returned in *save
+// (if save is not nil).
+func lookdot0(s *types.Sym, t *types.Type, save **types.Field, ignorecase bool) int {
+	u := t
+	if u.IsPtr() {
+		u = u.Elem()
+	}
+
+	c := 0
+	if u.IsStruct() || u.IsInterface() {
+		for _, f := range u.Fields().Slice() {
+			if f.Sym == s || (ignorecase && f.IsMethod() && strings.EqualFold(f.Sym.Name, s.Name)) {
+				if save != nil {
+					*save = f
+				}
+				c++
+			}
+		}
+	}
+
+	u = t
+	if t.Sym() != nil && t.IsPtr() && !t.Elem().IsPtr() {
+		// If t is a defined pointer type, then x.m is shorthand for (*x).m.
+		u = t.Elem()
+	}
+	u = types.ReceiverBaseType(u)
+	if u != nil {
+		for _, f := range u.Methods().Slice() {
+			if f.Embedded == 0 && (f.Sym == s || (ignorecase && strings.EqualFold(f.Sym.Name, s.Name))) {
+				if save != nil {
+					*save = f
+				}
+				c++
+			}
+		}
+	}
+
+	return c
+}
+
+var slist []symlink
+
+// Code to help generate trampoline functions for methods on embedded
+// types. These are approx the same as the corresponding adddot
+// routines except that they expect to be called with unique tasks and
+// they return the actual methods.
+
+type symlink struct {
+	field *types.Field
+}
diff --git a/src/cmd/compile/internal/typecheck/syms.go b/src/cmd/compile/internal/typecheck/syms.go
new file mode 100644
index 0000000000..ab3384bf90
--- /dev/null
+++ b/src/cmd/compile/internal/typecheck/syms.go
@@ -0,0 +1,104 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typecheck
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/obj"
+	"cmd/internal/src"
+)
+
+func LookupRuntime(name string) *ir.Name {
+	s := ir.Pkgs.Runtime.Lookup(name)
+	if s == nil || s.Def == nil {
+		base.Fatalf("syslook: can't find runtime.%s", name)
+	}
+	return ir.AsNode(s.Def).(*ir.Name)
+}
+
+// SubstArgTypes substitutes the given list of types for
+// successive occurrences of the "any" placeholder in the
+// type syntax expression n.Type.
+// The result of SubstArgTypes MUST be assigned back to old, e.g.
+// 	n.Left = SubstArgTypes(n.Left, t1, t2)
+func SubstArgTypes(old *ir.Name, types_ ...*types.Type) *ir.Name {
+	n := old.CloneName()
+
+	for _, t := range types_ {
+		types.CalcSize(t)
+	}
+	n.SetType(types.SubstAny(n.Type(), &types_))
+	if len(types_) > 0 {
+		base.Fatalf("substArgTypes: too many argument types")
+	}
+	return n
+}
+
+// AutoLabel generates a new Name node for use with
+// an automatically generated label.
+// prefix is a short mnemonic (e.g. ".s" for switch)
+// to help with debugging.
+// It should begin with "." to avoid conflicts with
+// user labels.
+func AutoLabel(prefix string) *types.Sym {
+	if prefix[0] != '.' {
+		base.Fatalf("autolabel prefix must start with '.', have %q", prefix)
+	}
+	fn := ir.CurFunc
+	if ir.CurFunc == nil {
+		base.Fatalf("autolabel outside function")
+	}
+	n := fn.Label
+	fn.Label++
+	return LookupNum(prefix, int(n))
+}
+
+func Lookup(name string) *types.Sym {
+	return types.LocalPkg.Lookup(name)
+}
+
+// loadsys loads the definitions for the low-level runtime functions,
+// so that the compiler can generate calls to them,
+// but does not make them visible to user code.
+func loadsys() {
+	types.Block = 1
+
+	inimport = true
+	TypecheckAllowed = true
+
+	typs := runtimeTypes()
+	for _, d := range &runtimeDecls {
+		sym := ir.Pkgs.Runtime.Lookup(d.name)
+		typ := typs[d.typ]
+		switch d.tag {
+		case funcTag:
+			importfunc(ir.Pkgs.Runtime, src.NoXPos, sym, typ)
+		case varTag:
+			importvar(ir.Pkgs.Runtime, src.NoXPos, sym, typ)
+		default:
+			base.Fatalf("unhandled declaration tag %v", d.tag)
+		}
+	}
+
+	TypecheckAllowed = false
+	inimport = false
+}
+
+// LookupRuntimeFunc looks up Go function name in package runtime. This function
+// must follow the internal calling convention.
+func LookupRuntimeFunc(name string) *obj.LSym {
+	s := ir.Pkgs.Runtime.Lookup(name)
+	s.SetFunc(true)
+	return s.Linksym()
+}
+
+// LookupRuntimeVar looks up a variable (or assembly function) name in package
+// runtime. If this is a function, it may have a special calling
+// convention.
+func LookupRuntimeVar(name string) *obj.LSym {
+	return ir.Pkgs.Runtime.Lookup(name).Linksym()
+}
diff --git a/src/cmd/compile/internal/gc/types.go b/src/cmd/compile/internal/typecheck/target.go
similarity index 51%
rename from src/cmd/compile/internal/gc/types.go
rename to src/cmd/compile/internal/typecheck/target.go
index e46735df28..018614d68b 100644
--- a/src/cmd/compile/internal/gc/types.go
+++ b/src/cmd/compile/internal/typecheck/target.go
@@ -2,4 +2,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package gc
+//go:generate go run mkbuiltin.go
+
+package typecheck
+
+import "cmd/compile/internal/ir"
+
+// Target is the package being compiled.
+var Target *ir.Package
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/typecheck/typecheck.go
similarity index 92%
rename from src/cmd/compile/internal/gc/typecheck.go
rename to src/cmd/compile/internal/typecheck/typecheck.go
index 0552dd180f..2abf0a7824 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/typecheck/typecheck.go
@@ -2,35 +2,46 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package gc
+package typecheck
 
 import (
-	"cmd/compile/internal/base"
-	"cmd/compile/internal/ir"
-	"cmd/compile/internal/types"
 	"fmt"
 	"go/constant"
 	"go/token"
 	"strings"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
 )
 
+// Function collecting autotmps generated during typechecking,
+// to be included in the package-level init function.
+var InitTodoFunc = ir.NewFunc(base.Pos)
+
+var inimport bool // set during import
+
+var decldepth int32
+
+var TypecheckAllowed bool
+
 var (
 	NeedFuncSym     = func(*types.Sym) {}
 	NeedITab        = func(t, itype *types.Type) {}
 	NeedRuntimeType = func(*types.Type) {}
 )
 
-func TypecheckInit() {
+func Init() {
 	initUniverse()
-	dclcontext = ir.PEXTERN
+	DeclContext = ir.PEXTERN
 	base.Timer.Start("fe", "loadsys")
 	loadsys()
 }
 
-func TypecheckPackage() {
-	finishUniverse()
+func Package() {
+	declareUniverse()
 
-	typecheckok = true
+	TypecheckAllowed = true
 
 	// Process top-level declarations in phases.
 
@@ -47,7 +58,7 @@ func TypecheckPackage() {
 	for i := 0; i < len(Target.Decls); i++ {
 		n := Target.Decls[i]
 		if op := n.Op(); op != ir.ODCL && op != ir.OAS && op != ir.OAS2 && (op != ir.ODCLTYPE || !n.(*ir.Decl).X.Name().Alias()) {
-			Target.Decls[i] = typecheck(n, ctxStmt)
+			Target.Decls[i] = Stmt(n)
 		}
 	}
 
@@ -59,7 +70,7 @@ func TypecheckPackage() {
 	for i := 0; i < len(Target.Decls); i++ {
 		n := Target.Decls[i]
 		if op := n.Op(); op == ir.ODCL || op == ir.OAS || op == ir.OAS2 || op == ir.ODCLTYPE && n.(*ir.Decl).X.Name().Alias() {
-			Target.Decls[i] = typecheck(n, ctxStmt)
+			Target.Decls[i] = Stmt(n)
 		}
 	}
 
@@ -70,7 +81,7 @@ func TypecheckPackage() {
 	for i := 0; i < len(Target.Decls); i++ {
 		n := Target.Decls[i]
 		if n.Op() == ir.ODCLFUNC {
-			TypecheckFuncBody(n.(*ir.Func))
+			FuncBody(n.(*ir.Func))
 			fcount++
 		}
 	}
@@ -81,12 +92,12 @@ func TypecheckPackage() {
 	base.Timer.Start("fe", "typecheck", "externdcls")
 	for i, n := range Target.Externs {
 		if n.Op() == ir.ONAME {
-			Target.Externs[i] = typecheck(Target.Externs[i], ctxExpr)
+			Target.Externs[i] = Expr(Target.Externs[i])
 		}
 	}
 
 	// Phase 5: With all user code type-checked, it's now safe to verify map keys.
-	checkMapKeys()
+	CheckMapKeys()
 
 	// Phase 6: Decide how to capture closed variables.
 	// This needs to run before escape analysis,
@@ -97,28 +108,28 @@ func TypecheckPackage() {
 			n := n.(*ir.Func)
 			if n.OClosure != nil {
 				ir.CurFunc = n
-				capturevars(n)
+				CaptureVars(n)
 			}
 		}
 	}
-	capturevarscomplete = true
+	CaptureVarsComplete = true
 	ir.CurFunc = nil
 
 	if base.Debug.TypecheckInl != 0 {
 		// Typecheck imported function bodies if Debug.l > 1,
 		// otherwise lazily when used or re-exported.
-		TypecheckImports()
+		AllImportedBodies()
 	}
 }
 
-func TypecheckAssignExpr(n ir.Node) ir.Node { return typecheck(n, ctxExpr|ctxAssign) }
-func TypecheckExpr(n ir.Node) ir.Node       { return typecheck(n, ctxExpr) }
-func TypecheckStmt(n ir.Node) ir.Node       { return typecheck(n, ctxStmt) }
+func AssignExpr(n ir.Node) ir.Node { return check(n, ctxExpr|ctxAssign) }
+func Expr(n ir.Node) ir.Node       { return check(n, ctxExpr) }
+func Stmt(n ir.Node) ir.Node       { return check(n, ctxStmt) }
 
-func TypecheckExprs(exprs []ir.Node) { typecheckslice(exprs, ctxExpr) }
-func TypecheckStmts(stmts []ir.Node) { typecheckslice(stmts, ctxStmt) }
+func Exprs(exprs []ir.Node) { typecheckslice(exprs, ctxExpr) }
+func Stmts(stmts []ir.Node) { typecheckslice(stmts, ctxStmt) }
 
-func TypecheckCall(call *ir.CallExpr) {
+func Call(call *ir.CallExpr) {
 	t := call.X.Type()
 	if t == nil {
 		panic("misuse of Call")
@@ -127,21 +138,21 @@ func TypecheckCall(call *ir.CallExpr) {
 	if t.NumResults() > 0 {
 		ctx = ctxExpr | ctxMultiOK
 	}
-	if typecheck(call, ctx) != call {
+	if check(call, ctx) != call {
 		panic("bad typecheck")
 	}
 }
 
-func TypecheckCallee(n ir.Node) ir.Node {
-	return typecheck(n, ctxExpr|ctxCallee)
+func Callee(n ir.Node) ir.Node {
+	return check(n, ctxExpr|ctxCallee)
 }
 
-func TypecheckFuncBody(n *ir.Func) {
+func FuncBody(n *ir.Func) {
 	ir.CurFunc = n
 	decldepth = 1
 	errorsBefore := base.Errors()
-	typecheckslice(n.Body, ctxStmt)
-	checkreturn(n)
+	Stmts(n.Body)
+	CheckReturn(n)
 	if base.Errors() > errorsBefore {
 		n.Body.Set(nil) // type errors; do not compile
 	}
@@ -152,10 +163,10 @@ func TypecheckFuncBody(n *ir.Func) {
 
 var importlist []*ir.Func
 
-func TypecheckImports() {
+func AllImportedBodies() {
 	for _, n := range importlist {
 		if n.Inl != nil {
-			typecheckinl(n)
+			ImportedBody(n)
 		}
 	}
 }
@@ -221,8 +232,8 @@ const (
 
 var typecheckdefstack []ir.Node
 
-// resolve ONONAME to definition, if any.
-func resolve(n ir.Node) (res ir.Node) {
+// Resolve ONONAME to definition, if any.
+func Resolve(n ir.Node) (res ir.Node) {
 	if n == nil || n.Op() != ir.ONONAME {
 		return n
 	}
@@ -235,7 +246,7 @@ func resolve(n ir.Node) (res ir.Node) {
 	if sym := n.Sym(); sym.Pkg != types.LocalPkg {
 		// We might have an ir.Ident from oldname or importDot.
 		if id, ok := n.(*ir.Ident); ok {
-			if pkgName := dotImportRefs[id]; pkgName != nil {
+			if pkgName := DotImportRefs[id]; pkgName != nil {
 				pkgName.Used = true
 			}
 		}
@@ -266,7 +277,7 @@ func resolve(n ir.Node) (res ir.Node) {
 
 func typecheckslice(l []ir.Node, top int) {
 	for i := range l {
-		l[i] = typecheck(l[i], top)
+		l[i] = check(l[i], top)
 	}
 }
 
@@ -348,23 +359,23 @@ func cycleTrace(cycle []ir.Node) string {
 
 var typecheck_tcstack []ir.Node
 
-func typecheckFunc(fn *ir.Func) {
-	new := typecheck(fn, ctxStmt)
+func Func(fn *ir.Func) {
+	new := Stmt(fn)
 	if new != fn {
 		base.Fatalf("typecheck changed func")
 	}
 }
 
 func typecheckNtype(n ir.Ntype) ir.Ntype {
-	return typecheck(n, ctxType).(ir.Ntype)
+	return check(n, ctxType).(ir.Ntype)
 }
 
-// typecheck type checks node n.
-// The result of typecheck MUST be assigned back to n, e.g.
-// 	n.Left = typecheck(n.Left, top)
-func typecheck(n ir.Node, top int) (res ir.Node) {
+// check type checks node n.
+// The result of check MUST be assigned back to n, e.g.
+// 	n.Left = check(n.Left, top)
+func check(n ir.Node, top int) (res ir.Node) {
 	// cannot type check until all the source has been parsed
-	if !typecheckok {
+	if !TypecheckAllowed {
 		base.Fatalf("early typecheck")
 	}
 
@@ -385,7 +396,7 @@ func typecheck(n ir.Node, top int) (res ir.Node) {
 	}
 
 	// Resolve definition of name and value of iota lazily.
-	n = resolve(n)
+	n = Resolve(n)
 
 	// Skip typecheck if already done.
 	// But re-typecheck ONAME/OTYPE/OLITERAL/OPACK node in case context has changed.
@@ -504,7 +515,7 @@ func typecheck(n ir.Node, top int) (res ir.Node) {
 		}
 	}
 	if t != nil {
-		n = evalConst(n)
+		n = EvalConst(n)
 		t = n.Type()
 	}
 
@@ -555,7 +566,7 @@ func typecheck(n ir.Node, top int) (res ir.Node) {
 // 	n.Left = indexlit(n.Left)
 func indexlit(n ir.Node) ir.Node {
 	if n != nil && n.Type() != nil && n.Type().Kind() == types.TIDEAL {
-		return defaultlit(n, types.Types[types.TINT])
+		return DefaultLit(n, types.Types[types.TINT])
 	}
 	return n
 }
@@ -642,7 +653,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OTSLICE:
 		n := n.(*ir.SliceType)
-		n.Elem = typecheck(n.Elem, ctxType)
+		n.Elem = check(n.Elem, ctxType)
 		if n.Elem.Type() == nil {
 			return n
 		}
@@ -653,7 +664,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OTARRAY:
 		n := n.(*ir.ArrayType)
-		n.Elem = typecheck(n.Elem, ctxType)
+		n.Elem = check(n.Elem, ctxType)
 		if n.Elem.Type() == nil {
 			return n
 		}
@@ -664,7 +675,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			}
 			return n
 		}
-		n.Len = indexlit(typecheck(n.Len, ctxExpr))
+		n.Len = indexlit(Expr(n.Len))
 		size := n.Len
 		if ir.ConstType(size) != constant.Int {
 			switch {
@@ -697,8 +708,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OTMAP:
 		n := n.(*ir.MapType)
-		n.Key = typecheck(n.Key, ctxType)
-		n.Elem = typecheck(n.Elem, ctxType)
+		n.Key = check(n.Key, ctxType)
+		n.Elem = check(n.Elem, ctxType)
 		l := n.Key
 		r := n.Elem
 		if l.Type() == nil || r.Type() == nil {
@@ -716,7 +727,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OTCHAN:
 		n := n.(*ir.ChanType)
-		n.Elem = typecheck(n.Elem, ctxType)
+		n.Elem = check(n.Elem, ctxType)
 		l := n.Elem
 		if l.Type() == nil {
 			return n
@@ -729,7 +740,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OTSTRUCT:
 		n := n.(*ir.StructType)
-		n.SetOTYPE(tostruct(n.Fields))
+		n.SetOTYPE(NewStructType(n.Fields))
 		return n
 
 	case ir.OTINTER:
@@ -739,13 +750,13 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OTFUNC:
 		n := n.(*ir.FuncType)
-		n.SetOTYPE(functype(n.Recv, n.Params, n.Results))
+		n.SetOTYPE(NewFuncType(n.Recv, n.Params, n.Results))
 		return n
 
 	// type or expr
 	case ir.ODEREF:
 		n := n.(*ir.StarExpr)
-		n.X = typecheck(n.X, ctxExpr|ctxType)
+		n.X = check(n.X, ctxExpr|ctxType)
 		l := n.X
 		t := l.Type()
 		if t == nil {
@@ -806,8 +817,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			l, r = n.X, n.Y
 			setLR = func() { n.X = l; n.Y = r }
 		}
-		l = typecheck(l, ctxExpr)
-		r = typecheck(r, ctxExpr)
+		l = Expr(l)
+		r = Expr(r)
 		setLR()
 		if l.Type() == nil || r.Type() == nil {
 			n.SetType(nil)
@@ -826,7 +837,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			op = n.AsOp
 		}
 		if op == ir.OLSH || op == ir.ORSH {
-			r = defaultlit(r, types.Types[types.TUINT])
+			r = DefaultLit(r, types.Types[types.TUINT])
 			setLR()
 			t := r.Type()
 			if !t.IsInteger() {
@@ -1001,7 +1012,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 		if iscmp[n.Op()] {
 			t = types.UntypedBool
 			n.SetType(t)
-			if con := evalConst(n); con.Op() == ir.OLITERAL {
+			if con := EvalConst(n); con.Op() == ir.OLITERAL {
 				return con
 			}
 			l, r = defaultlit2(l, r, true)
@@ -1042,7 +1053,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OBITNOT, ir.ONEG, ir.ONOT, ir.OPLUS:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		l := n.X
 		t := l.Type()
 		if t == nil {
@@ -1061,7 +1072,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 	// exprs
 	case ir.OADDR:
 		n := n.(*ir.AddrExpr)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		if n.X.Type() == nil {
 			n.SetType(nil)
 			return n
@@ -1080,7 +1091,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 					base.Fatalf("found non-orig name node %v", r) // TODO(mdempsky): What does this mean?
 				}
 				r.Name().SetAddrtaken(true)
-				if r.Name().IsClosureVar() && !capturevarscomplete {
+				if r.Name().IsClosureVar() && !CaptureVarsComplete {
 					// Mark the original variable as Addrtaken so that capturevars
 					// knows not to pass it by value.
 					// But if the capturevars phase is complete, don't touch it,
@@ -1088,7 +1099,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 					r.Name().Defn.Name().SetAddrtaken(true)
 				}
 			}
-			n.X = defaultlit(n.X, nil)
+			n.X = DefaultLit(n.X, nil)
 			if n.X.Type() == nil {
 				n.SetType(nil)
 				return n
@@ -1104,7 +1115,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 	case ir.OXDOT, ir.ODOT:
 		n := n.(*ir.SelectorExpr)
 		if n.Op() == ir.OXDOT {
-			n = adddot(n)
+			n = AddImplicitDots(n)
 			n.SetOp(ir.ODOT)
 			if n.X == nil {
 				n.SetType(nil)
@@ -1112,9 +1123,9 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			}
 		}
 
-		n.X = typecheck(n.X, ctxExpr|ctxType)
+		n.X = check(n.X, ctxExpr|ctxType)
 
-		n.X = defaultlit(n.X, nil)
+		n.X = DefaultLit(n.X, nil)
 
 		t := n.X.Type()
 		if t == nil {
@@ -1177,8 +1188,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.ODOTTYPE:
 		n := n.(*ir.TypeAssertExpr)
-		n.X = typecheck(n.X, ctxExpr)
-		n.X = defaultlit(n.X, nil)
+		n.X = Expr(n.X)
+		n.X = DefaultLit(n.X, nil)
 		l := n.X
 		t := l.Type()
 		if t == nil {
@@ -1192,7 +1203,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 		}
 
 		if n.Ntype != nil {
-			n.Ntype = typecheck(n.Ntype, ctxType)
+			n.Ntype = check(n.Ntype, ctxType)
 			n.SetType(n.Ntype.Type())
 			n.Ntype = nil
 			if n.Type() == nil {
@@ -1223,11 +1234,11 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OINDEX:
 		n := n.(*ir.IndexExpr)
-		n.X = typecheck(n.X, ctxExpr)
-		n.X = defaultlit(n.X, nil)
+		n.X = Expr(n.X)
+		n.X = DefaultLit(n.X, nil)
 		n.X = implicitstar(n.X)
 		l := n.X
-		n.Index = typecheck(n.Index, ctxExpr)
+		n.Index = Expr(n.Index)
 		r := n.Index
 		t := l.Type()
 		if t == nil || r.Type() == nil {
@@ -1273,7 +1284,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			}
 
 		case types.TMAP:
-			n.Index = assignconv(n.Index, t.Key(), "map index")
+			n.Index = AssignConv(n.Index, t.Key(), "map index")
 			n.SetType(t.Elem())
 			n.SetOp(ir.OINDEXMAP)
 			n.Assigned = false
@@ -1282,8 +1293,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.ORECV:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
-		n.X = defaultlit(n.X, nil)
+		n.X = Expr(n.X)
+		n.X = DefaultLit(n.X, nil)
 		l := n.X
 		t := l.Type()
 		if t == nil {
@@ -1307,9 +1318,9 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OSEND:
 		n := n.(*ir.SendStmt)
-		n.Chan = typecheck(n.Chan, ctxExpr)
-		n.Value = typecheck(n.Value, ctxExpr)
-		n.Chan = defaultlit(n.Chan, nil)
+		n.Chan = Expr(n.Chan)
+		n.Value = Expr(n.Value)
+		n.Chan = DefaultLit(n.Chan, nil)
 		t := n.Chan.Type()
 		if t == nil {
 			return n
@@ -1324,7 +1335,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			return n
 		}
 
-		n.Value = assignconv(n.Value, t.Elem(), "send")
+		n.Value = AssignConv(n.Value, t.Elem(), "send")
 		if n.Value.Type() == nil {
 			return n
 		}
@@ -1353,11 +1364,11 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			base.Fatalf("expected 2 params (len, cap) for OSLICEHEADER, got %d", x)
 		}
 
-		n.Ptr = typecheck(n.Ptr, ctxExpr)
-		l := typecheck(n.LenCap[0], ctxExpr)
-		c := typecheck(n.LenCap[1], ctxExpr)
-		l = defaultlit(l, types.Types[types.TINT])
-		c = defaultlit(c, types.Types[types.TINT])
+		n.Ptr = Expr(n.Ptr)
+		l := Expr(n.LenCap[0])
+		c := Expr(n.LenCap[1])
+		l = DefaultLit(l, types.Types[types.TINT])
+		c = DefaultLit(c, types.Types[types.TINT])
 
 		if ir.IsConst(l, constant.Int) && ir.Int64Val(l) < 0 {
 			base.Fatalf("len for OSLICEHEADER must be non-negative")
@@ -1399,10 +1410,10 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			base.Fatalf("missing slice argument to copy for OMAKESLICECOPY")
 		}
 
-		n.Len = typecheck(n.Len, ctxExpr)
-		n.Cap = typecheck(n.Cap, ctxExpr)
+		n.Len = Expr(n.Len)
+		n.Cap = Expr(n.Cap)
 
-		n.Len = defaultlit(n.Len, types.Types[types.TINT])
+		n.Len = DefaultLit(n.Len, types.Types[types.TINT])
 
 		if !n.Len.Type().IsInteger() && n.Type().Kind() != types.TIDEAL {
 			base.Errorf("non-integer len argument in OMAKESLICECOPY")
@@ -1420,13 +1431,13 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OSLICE, ir.OSLICE3:
 		n := n.(*ir.SliceExpr)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		low, high, max := n.SliceBounds()
 		hasmax := n.Op().IsSlice3()
-		low = typecheck(low, ctxExpr)
-		high = typecheck(high, ctxExpr)
-		max = typecheck(max, ctxExpr)
-		n.X = defaultlit(n.X, nil)
+		low = Expr(low)
+		high = Expr(high)
+		max = Expr(max)
+		n.X = DefaultLit(n.X, nil)
 		low = indexlit(low)
 		high = indexlit(high)
 		max = indexlit(max)
@@ -1443,9 +1454,9 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 				return n
 			}
 
-			addr := nodAddr(n.X)
+			addr := NodAddr(n.X)
 			addr.SetImplicit(true)
-			n.X = typecheck(addr, ctxExpr)
+			n.X = Expr(addr)
 			l = n.X
 		}
 		t := l.Type()
@@ -1500,8 +1511,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 		if top == ctxStmt {
 			n.Use = ir.CallUseStmt
 		}
-		typecheckslice(n.Init(), ctxStmt) // imported rewritten f(g()) calls (#30907)
-		n.X = typecheck(n.X, ctxExpr|ctxType|ctxCallee)
+		Stmts(n.Init()) // imported rewritten f(g()) calls (#30907)
+		n.X = check(n.X, ctxExpr|ctxType|ctxCallee)
 		if n.X.Diag() {
 			n.SetDiag(true)
 		}
@@ -1523,7 +1534,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 				n.SetOp(l.BuiltinOp)
 				n.X = nil
 				n.SetTypecheck(0) // re-typechecking new op is OK, not a loop
-				return typecheck(n, top)
+				return check(n, top)
 
 			case ir.OCAP, ir.OCLOSE, ir.OIMAG, ir.OLEN, ir.OPANIC, ir.OREAL:
 				typecheckargs(n)
@@ -1535,7 +1546,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 					return n
 				}
 				u := ir.NewUnaryExpr(n.Pos(), l.BuiltinOp, arg)
-				return typecheck(ir.InitExpr(n.Init(), u), top) // typecheckargs can add to old.Init
+				return check(ir.InitExpr(n.Init(), u), top) // typecheckargs can add to old.Init
 
 			case ir.OCOMPLEX, ir.OCOPY:
 				typecheckargs(n)
@@ -1545,12 +1556,12 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 					return n
 				}
 				b := ir.NewBinaryExpr(n.Pos(), l.BuiltinOp, arg1, arg2)
-				return typecheck(ir.InitExpr(n.Init(), b), top) // typecheckargs can add to old.Init
+				return check(ir.InitExpr(n.Init(), b), top) // typecheckargs can add to old.Init
 			}
 			panic("unreachable")
 		}
 
-		n.X = defaultlit(n.X, nil)
+		n.X = DefaultLit(n.X, nil)
 		l = n.X
 		if l.Op() == ir.OTYPE {
 			if n.IsDDD {
@@ -1653,8 +1664,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OCAP, ir.OLEN:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
-		n.X = defaultlit(n.X, nil)
+		n.X = Expr(n.X)
+		n.X = DefaultLit(n.X, nil)
 		n.X = implicitstar(n.X)
 		l := n.X
 		t := l.Type()
@@ -1680,7 +1691,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OREAL, ir.OIMAG:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		l := n.X
 		t := l.Type()
 		if t == nil {
@@ -1705,8 +1716,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OCOMPLEX:
 		n := n.(*ir.BinaryExpr)
-		l := typecheck(n.X, ctxExpr)
-		r := typecheck(n.Y, ctxExpr)
+		l := Expr(n.X)
+		r := Expr(n.Y)
 		if l.Type() == nil || r.Type() == nil {
 			n.SetType(nil)
 			return n
@@ -1746,8 +1757,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OCLOSE:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
-		n.X = defaultlit(n.X, nil)
+		n.X = Expr(n.X)
+		n.X = DefaultLit(n.X, nil)
 		l := n.X
 		t := l.Type()
 		if t == nil {
@@ -1797,7 +1808,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			return n
 		}
 
-		args[1] = assignconv(r, l.Type().Key(), "delete")
+		args[1] = AssignConv(r, l.Type().Key(), "delete")
 		return n
 
 	case ir.OAPPEND:
@@ -1843,11 +1854,11 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			}
 
 			if t.Elem().IsKind(types.TUINT8) && args[1].Type().IsString() {
-				args[1] = defaultlit(args[1], types.Types[types.TSTRING])
+				args[1] = DefaultLit(args[1], types.Types[types.TSTRING])
 				return n
 			}
 
-			args[1] = assignconv(args[1], t.Underlying(), "append")
+			args[1] = AssignConv(args[1], t.Underlying(), "append")
 			return n
 		}
 
@@ -1856,7 +1867,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			if n.Type() == nil {
 				continue
 			}
-			as[i] = assignconv(n, t.Elem(), "append")
+			as[i] = AssignConv(n, t.Elem(), "append")
 			types.CheckSize(as[i].Type()) // ensure width is calculated for backend
 		}
 		return n
@@ -1864,10 +1875,10 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 	case ir.OCOPY:
 		n := n.(*ir.BinaryExpr)
 		n.SetType(types.Types[types.TINT])
-		n.X = typecheck(n.X, ctxExpr)
-		n.X = defaultlit(n.X, nil)
-		n.Y = typecheck(n.Y, ctxExpr)
-		n.Y = defaultlit(n.Y, nil)
+		n.X = Expr(n.X)
+		n.X = DefaultLit(n.X, nil)
+		n.Y = Expr(n.Y)
+		n.Y = DefaultLit(n.Y, nil)
 		if n.X.Type() == nil || n.Y.Type() == nil {
 			n.SetType(nil)
 			return n
@@ -1905,7 +1916,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 	case ir.OCONV:
 		n := n.(*ir.ConvExpr)
 		types.CheckSize(n.Type()) // ensure width is calculated for backend
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		n.X = convlit1(n.X, n.Type(), true, nil)
 		t := n.X.Type()
 		if t == nil || n.Type() == nil {
@@ -1958,7 +1969,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 		n.Args.Set(nil)
 		l := args[0]
-		l = typecheck(l, ctxType)
+		l = check(l, ctxType)
 		t := l.Type()
 		if t == nil {
 			n.SetType(nil)
@@ -1982,12 +1993,12 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 			l = args[i]
 			i++
-			l = typecheck(l, ctxExpr)
+			l = Expr(l)
 			var r ir.Node
 			if i < len(args) {
 				r = args[i]
 				i++
-				r = typecheck(r, ctxExpr)
+				r = Expr(r)
 			}
 
 			if l.Type() == nil || (r != nil && r.Type() == nil) {
@@ -2009,8 +2020,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			if i < len(args) {
 				l = args[i]
 				i++
-				l = typecheck(l, ctxExpr)
-				l = defaultlit(l, types.Types[types.TINT])
+				l = Expr(l)
+				l = DefaultLit(l, types.Types[types.TINT])
 				if l.Type() == nil {
 					n.SetType(nil)
 					return n
@@ -2030,8 +2041,8 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			if i < len(args) {
 				l = args[i]
 				i++
-				l = typecheck(l, ctxExpr)
-				l = defaultlit(l, types.Types[types.TINT])
+				l = Expr(l)
+				l = DefaultLit(l, types.Types[types.TINT])
 				if l.Type() == nil {
 					n.SetType(nil)
 					return n
@@ -2063,7 +2074,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 			base.Fatalf("missing argument to new")
 		}
 		l := n.X
-		l = typecheck(l, ctxType)
+		l = check(l, ctxType)
 		t := l.Type()
 		if t == nil {
 			n.SetType(nil)
@@ -2080,17 +2091,17 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 		for i1, n1 := range ls {
 			// Special case for print: int constant is int64, not int.
 			if ir.IsConst(n1, constant.Int) {
-				ls[i1] = defaultlit(ls[i1], types.Types[types.TINT64])
+				ls[i1] = DefaultLit(ls[i1], types.Types[types.TINT64])
 			} else {
-				ls[i1] = defaultlit(ls[i1], nil)
+				ls[i1] = DefaultLit(ls[i1], nil)
 			}
 		}
 		return n
 
 	case ir.OPANIC:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
-		n.X = defaultlit(n.X, types.Types[types.TINTER])
+		n.X = Expr(n.X)
+		n.X = DefaultLit(n.X, types.Types[types.TINTER])
 		if n.X.Type() == nil {
 			n.SetType(nil)
 			return n
@@ -2118,7 +2129,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OITAB:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		t := n.X.Type()
 		if t == nil {
 			n.SetType(nil)
@@ -2139,7 +2150,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OSPTR:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		t := n.X.Type()
 		if t == nil {
 			n.SetType(nil)
@@ -2160,13 +2171,13 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OCFUNC:
 		n := n.(*ir.UnaryExpr)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		n.SetType(types.Types[types.TUINTPTR])
 		return n
 
 	case ir.OCONVNOP:
 		n := n.(*ir.ConvExpr)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		return n
 
 	// statements
@@ -2195,7 +2206,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OBLOCK:
 		n := n.(*ir.BlockStmt)
-		typecheckslice(n.List, ctxStmt)
+		Stmts(n.List)
 		return n
 
 	case ir.OLABEL:
@@ -2210,7 +2221,7 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.ODEFER, ir.OGO:
 		n := n.(*ir.GoDeferStmt)
-		n.Call = typecheck(n.Call, ctxStmt|ctxExpr)
+		n.Call = check(n.Call, ctxStmt|ctxExpr)
 		if !n.Call.Diag() {
 			checkdefergo(n)
 		}
@@ -2218,37 +2229,37 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.OFOR, ir.OFORUNTIL:
 		n := n.(*ir.ForStmt)
-		typecheckslice(n.Init(), ctxStmt)
+		Stmts(n.Init())
 		decldepth++
-		n.Cond = typecheck(n.Cond, ctxExpr)
-		n.Cond = defaultlit(n.Cond, nil)
+		n.Cond = Expr(n.Cond)
+		n.Cond = DefaultLit(n.Cond, nil)
 		if n.Cond != nil {
 			t := n.Cond.Type()
 			if t != nil && !t.IsBoolean() {
 				base.Errorf("non-bool %L used as for condition", n.Cond)
 			}
 		}
-		n.Post = typecheck(n.Post, ctxStmt)
+		n.Post = Stmt(n.Post)
 		if n.Op() == ir.OFORUNTIL {
-			typecheckslice(n.Late, ctxStmt)
+			Stmts(n.Late)
 		}
-		typecheckslice(n.Body, ctxStmt)
+		Stmts(n.Body)
 		decldepth--
 		return n
 
 	case ir.OIF:
 		n := n.(*ir.IfStmt)
-		typecheckslice(n.Init(), ctxStmt)
-		n.Cond = typecheck(n.Cond, ctxExpr)
-		n.Cond = defaultlit(n.Cond, nil)
+		Stmts(n.Init())
+		n.Cond = Expr(n.Cond)
+		n.Cond = DefaultLit(n.Cond, nil)
 		if n.Cond != nil {
 			t := n.Cond.Type()
 			if t != nil && !t.IsBoolean() {
 				base.Errorf("non-bool %L used as if condition", n.Cond)
 			}
 		}
-		typecheckslice(n.Body, ctxStmt)
-		typecheckslice(n.Else, ctxStmt)
+		Stmts(n.Body)
+		Stmts(n.Else)
 		return n
 
 	case ir.ORETURN:
@@ -2294,12 +2305,12 @@ func typecheck1(n ir.Node, top int) (res ir.Node) {
 
 	case ir.ODCLCONST:
 		n := n.(*ir.Decl)
-		n.X = typecheck(n.X, ctxExpr)
+		n.X = Expr(n.X)
 		return n
 
 	case ir.ODCLTYPE:
 		n := n.(*ir.Decl)
-		n.X = typecheck(n.X, ctxType)
+		n.X = check(n.X, ctxType)
 		types.CheckSize(n.X.Type())
 		return n
 	}
@@ -2317,14 +2328,14 @@ func typecheckargs(n ir.Node) {
 	case *ir.CallExpr:
 		list = n.Args
 		if n.IsDDD {
-			typecheckslice(list, ctxExpr)
+			Exprs(list)
 			return
 		}
 	case *ir.ReturnStmt:
 		list = n.Results
 	}
 	if len(list) != 1 {
-		typecheckslice(list, ctxExpr)
+		Exprs(list)
 		return
 	}
 
@@ -2351,11 +2362,11 @@ func typecheckargs(n ir.Node) {
 	// will reassociate them later when it's appropriate.
 	static := ir.CurFunc == nil
 	if static {
-		ir.CurFunc = initTodo
+		ir.CurFunc = InitTodoFunc
 	}
 	list = nil
 	for _, f := range t.FieldSlice() {
-		t := temp(f.Type)
+		t := Temp(f.Type)
 		as.PtrInit().Append(ir.NewDecl(base.Pos, ir.ODCL, t))
 		as.Lhs.Append(t)
 		list = append(list, t)
@@ -2371,7 +2382,7 @@ func typecheckargs(n ir.Node) {
 		n.Results.Set(list)
 	}
 
-	n.PtrInit().Append(typecheck(as, ctxStmt))
+	n.PtrInit().Append(Stmt(as))
 }
 
 func checksliceindex(l ir.Node, r ir.Node, tp *types.Type) bool {
@@ -2483,7 +2494,7 @@ func implicitstar(n ir.Node) ir.Node {
 	}
 	star := ir.NewStarExpr(base.Pos, n)
 	star.SetImplicit(true)
-	return typecheck(star, ctxExpr)
+	return Expr(star)
 }
 
 func needOneArg(n *ir.CallExpr, f string, args ...interface{}) (ir.Node, bool) {
@@ -2563,7 +2574,7 @@ func typecheckMethodExpr(n *ir.SelectorExpr) (res ir.Node) {
 			n.SetType(nil)
 			return n
 		}
-		expandmeth(mt)
+		CalcMethods(mt)
 		ms = mt.AllMethods()
 
 		// The method expression T.m requires a wrapper when T
@@ -2599,7 +2610,7 @@ func typecheckMethodExpr(n *ir.SelectorExpr) (res ir.Node) {
 	}
 
 	me := ir.NewMethodExpr(n.Pos(), n.X.Type(), m)
-	me.SetType(methodfunc(m.Type, n.X.Type()))
+	me.SetType(NewMethodType(m.Type, n.X.Type()))
 	f := NewName(ir.MethodSym(t, m.Sym))
 	f.Class_ = ir.PFUNC
 	f.SetType(me.Type())
@@ -2654,7 +2665,7 @@ func lookdot(n *ir.SelectorExpr, t *types.Type, dostrcmp int) *types.Field {
 			if n.X.Type().IsPtr() {
 				star := ir.NewStarExpr(base.Pos, n.X)
 				star.SetImplicit(true)
-				n.X = typecheck(star, ctxExpr)
+				n.X = Expr(star)
 			}
 
 			n.SetOp(ir.ODOTINTER)
@@ -2674,13 +2685,13 @@ func lookdot(n *ir.SelectorExpr, t *types.Type, dostrcmp int) *types.Field {
 		if !types.Identical(rcvr, tt) {
 			if rcvr.IsPtr() && types.Identical(rcvr.Elem(), tt) {
 				checklvalue(n.X, "call pointer method on")
-				addr := nodAddr(n.X)
+				addr := NodAddr(n.X)
 				addr.SetImplicit(true)
-				n.X = typecheck(addr, ctxType|ctxExpr)
+				n.X = check(addr, ctxType|ctxExpr)
 			} else if tt.IsPtr() && (!rcvr.IsPtr() || rcvr.IsPtr() && rcvr.Elem().NotInHeap()) && types.Identical(tt.Elem(), rcvr) {
 				star := ir.NewStarExpr(base.Pos, n.X)
 				star.SetImplicit(true)
-				n.X = typecheck(star, ctxType|ctxExpr)
+				n.X = check(star, ctxType|ctxExpr)
 			} else if tt.IsPtr() && tt.Elem().IsPtr() && types.Identical(derefall(tt), derefall(rcvr)) {
 				base.Errorf("calling method %v with receiver %L requires explicit dereference", n.Sel, n.X)
 				for tt.IsPtr() {
@@ -2690,7 +2701,7 @@ func lookdot(n *ir.SelectorExpr, t *types.Type, dostrcmp int) *types.Field {
 					}
 					star := ir.NewStarExpr(base.Pos, n.X)
 					star.SetImplicit(true)
-					n.X = typecheck(star, ctxType|ctxExpr)
+					n.X = check(star, ctxType|ctxExpr)
 					tt = tt.Elem()
 				}
 			} else {
@@ -2967,7 +2978,7 @@ func pushtype(nn ir.Node, t *types.Type) ir.Node {
 		// For *T, return &T{...}.
 		n.Ntype = ir.TypeNode(t.Elem())
 
-		addr := nodAddrAt(n.Pos(), n)
+		addr := NodAddrAt(n.Pos(), n)
 		addr.SetImplicit(true)
 		return addr
 	}
@@ -2999,7 +3010,7 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 
 	// Need to handle [...]T arrays specially.
 	if array, ok := n.Ntype.(*ir.ArrayType); ok && array.Elem != nil && array.Len == nil {
-		array.Elem = typecheck(array.Elem, ctxType)
+		array.Elem = check(array.Elem, ctxType)
 		elemType := array.Elem.Type()
 		if elemType == nil {
 			n.SetType(nil)
@@ -3012,7 +3023,7 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 		return n
 	}
 
-	n.Ntype = ir.Node(typecheck(n.Ntype, ctxType)).(ir.Ntype)
+	n.Ntype = ir.Node(check(n.Ntype, ctxType)).(ir.Ntype)
 	t := n.Ntype.Type()
 	if t == nil {
 		n.SetType(nil)
@@ -3041,7 +3052,7 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 		for i3, l := range n.List {
 			ir.SetPos(l)
 			if l.Op() != ir.OKEY {
-				n.List[i3] = typecheck(l, ctxExpr)
+				n.List[i3] = Expr(l)
 				base.Errorf("missing key in map literal")
 				continue
 			}
@@ -3049,14 +3060,14 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 
 			r := l.Key
 			r = pushtype(r, t.Key())
-			r = typecheck(r, ctxExpr)
-			l.Key = assignconv(r, t.Key(), "map key")
+			r = Expr(r)
+			l.Key = AssignConv(r, t.Key(), "map key")
 			cs.add(base.Pos, l.Key, "key", "map literal")
 
 			r = l.Value
 			r = pushtype(r, t.Elem())
-			r = typecheck(r, ctxExpr)
-			l.Value = assignconv(r, t.Elem(), "map value")
+			r = Expr(r)
+			l.Value = AssignConv(r, t.Elem(), "map value")
 		}
 
 		n.SetOp(ir.OMAPLIT)
@@ -3072,7 +3083,7 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 			ls := n.List
 			for i, n1 := range ls {
 				ir.SetPos(n1)
-				n1 = typecheck(n1, ctxExpr)
+				n1 = Expr(n1)
 				ls[i] = n1
 				if i >= t.NumFields() {
 					if !errored {
@@ -3088,7 +3099,7 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 					base.Errorf("implicit assignment of unexported field '%s' in %v literal", s.Name, t)
 				}
 				// No pushtype allowed here. Must name fields for that.
-				n1 = assignconv(n1, f.Type, "field value")
+				n1 = AssignConv(n1, f.Type, "field value")
 				sk := ir.NewStructKeyExpr(base.Pos, f.Sym, n1)
 				sk.Offset = f.Offset
 				ls[i] = sk
@@ -3112,8 +3123,8 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 					// package, because of import dot. Redirect to correct sym
 					// before we do the lookup.
 					s := key.Sym()
-					if id, ok := key.(*ir.Ident); ok && dotImportRefs[id] != nil {
-						s = lookup(s.Name)
+					if id, ok := key.(*ir.Ident); ok && DotImportRefs[id] != nil {
+						s = Lookup(s.Name)
 					}
 
 					// An OXDOT uses the Sym field to hold
@@ -3134,7 +3145,7 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 						base.Errorf("mixture of field:value and value initializers")
 						errored = true
 					}
-					ls[i] = typecheck(ls[i], ctxExpr)
+					ls[i] = Expr(ls[i])
 					continue
 				}
 				l := l.(*ir.StructKeyExpr)
@@ -3170,8 +3181,8 @@ func typecheckcomplit(n *ir.CompLitExpr) (res ir.Node) {
 				l.Offset = f.Offset
 
 				// No pushtype allowed here. Tried and rejected.
-				l.Value = typecheck(l.Value, ctxExpr)
-				l.Value = assignconv(l.Value, f.Type, "field value")
+				l.Value = Expr(l.Value)
+				l.Value = AssignConv(l.Value, f.Type, "field value")
 			}
 		}
 
@@ -3201,8 +3212,8 @@ func typecheckarraylit(elemType *types.Type, bound int64, elts []ir.Node, ctx st
 		var kv *ir.KeyExpr
 		if elt.Op() == ir.OKEY {
 			elt := elt.(*ir.KeyExpr)
-			elt.Key = typecheck(elt.Key, ctxExpr)
-			key = indexconst(elt.Key)
+			elt.Key = Expr(elt.Key)
+			key = IndexConst(elt.Key)
 			if key < 0 {
 				if !elt.Key.Diag() {
 					if key == -2 {
@@ -3219,8 +3230,8 @@ func typecheckarraylit(elemType *types.Type, bound int64, elts []ir.Node, ctx st
 		}
 
 		r = pushtype(r, elemType)
-		r = typecheck(r, ctxExpr)
-		r = assignconv(r, elemType, ctx)
+		r = Expr(r)
+		r = AssignConv(r, elemType, ctx)
 		if kv != nil {
 			kv.Value = r
 		} else {
@@ -3328,15 +3339,15 @@ func typecheckas(n *ir.AssignStmt) {
 	// if the variable has a type (ntype) then typechecking
 	// will not look at defn, so it is okay (and desirable,
 	// so that the conversion below happens).
-	n.X = resolve(n.X)
+	n.X = Resolve(n.X)
 
 	if !ir.DeclaredBy(n.X, n) || n.X.Name().Ntype != nil {
-		n.X = typecheck(n.X, ctxExpr|ctxAssign)
+		n.X = AssignExpr(n.X)
 	}
 
 	// Use ctxMultiOK so we can emit an "N variables but M values" error
 	// to be consistent with typecheckas2 (#26616).
-	n.Y = typecheck(n.Y, ctxExpr|ctxMultiOK)
+	n.Y = check(n.Y, ctxExpr|ctxMultiOK)
 	checkassign(n, n.X)
 	if n.Y != nil && n.Y.Type() != nil {
 		if n.Y.Type().IsFuncArgStruct() {
@@ -3345,12 +3356,12 @@ func typecheckas(n *ir.AssignStmt) {
 			// to indicate failed typechecking.
 			n.Y.SetType(nil)
 		} else if n.X.Type() != nil {
-			n.Y = assignconv(n.Y, n.X.Type(), "assignment")
+			n.Y = AssignConv(n.Y, n.X.Type(), "assignment")
 		}
 	}
 
 	if ir.DeclaredBy(n.X, n) && n.X.Name().Ntype == nil {
-		n.Y = defaultlit(n.Y, nil)
+		n.Y = DefaultLit(n.Y, nil)
 		n.X.SetType(n.Y.Type())
 	}
 
@@ -3360,7 +3371,7 @@ func typecheckas(n *ir.AssignStmt) {
 	n.SetTypecheck(1)
 
 	if n.X.Typecheck() == 0 {
-		n.X = typecheck(n.X, ctxExpr|ctxAssign)
+		n.X = AssignExpr(n.X)
 	}
 	if !ir.IsBlank(n.X) {
 		types.CheckSize(n.X.Type()) // ensure width is calculated for backend
@@ -3382,20 +3393,20 @@ func typecheckas2(n *ir.AssignListStmt) {
 	ls := n.Lhs
 	for i1, n1 := range ls {
 		// delicate little dance.
-		n1 = resolve(n1)
+		n1 = Resolve(n1)
 		ls[i1] = n1
 
 		if !ir.DeclaredBy(n1, n) || n1.Name().Ntype != nil {
-			ls[i1] = typecheck(ls[i1], ctxExpr|ctxAssign)
+			ls[i1] = AssignExpr(ls[i1])
 		}
 	}
 
 	cl := len(n.Lhs)
 	cr := len(n.Rhs)
 	if cl > 1 && cr == 1 {
-		n.Rhs[0] = typecheck(n.Rhs[0], ctxExpr|ctxMultiOK)
+		n.Rhs[0] = check(n.Rhs[0], ctxExpr|ctxMultiOK)
 	} else {
-		typecheckslice(n.Rhs, ctxExpr)
+		Exprs(n.Rhs)
 	}
 	checkassignlist(n, n.Lhs)
 
@@ -3408,10 +3419,10 @@ func typecheckas2(n *ir.AssignListStmt) {
 		for il, nl := range ls {
 			nr := rs[il]
 			if nl.Type() != nil && nr.Type() != nil {
-				rs[il] = assignconv(nr, nl.Type(), "assignment")
+				rs[il] = AssignConv(nr, nl.Type(), "assignment")
 			}
 			if ir.DeclaredBy(nl, n) && nl.Name().Ntype == nil {
-				rs[il] = defaultlit(rs[il], nil)
+				rs[il] = DefaultLit(rs[il], nil)
 				nl.SetType(rs[il].Type())
 			}
 		}
@@ -3500,7 +3511,7 @@ out:
 	ls = n.Lhs
 	for i1, n1 := range ls {
 		if n1.Typecheck() == 0 {
-			ls[i1] = typecheck(ls[i1], ctxExpr|ctxAssign)
+			ls[i1] = AssignExpr(ls[i1])
 		}
 	}
 }
@@ -3519,7 +3530,7 @@ func typecheckfunc(n *ir.Func) {
 		}
 	}
 
-	n.Nname = typecheck(n.Nname, ctxExpr|ctxAssign).(*ir.Name)
+	n.Nname = AssignExpr(n.Nname).(*ir.Name)
 	t := n.Nname.Type()
 	if t == nil {
 		return
@@ -3533,7 +3544,7 @@ func typecheckfunc(n *ir.Func) {
 		}
 
 		n.Nname.SetSym(ir.MethodSym(rcvr.Type, n.Shortname))
-		declare(n.Nname, ir.PFUNC)
+		Declare(n.Nname, ir.PFUNC)
 	}
 
 	if base.Ctxt.Flag_dynlink && !inimport && n.Nname != nil {
@@ -3557,12 +3568,12 @@ func stringtoruneslit(n *ir.ConvExpr) ir.Node {
 
 	nn := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(n.Type()).(ir.Ntype), nil)
 	nn.List.Set(l)
-	return typecheck(nn, ctxExpr)
+	return Expr(nn)
 }
 
 var mapqueue []*ir.MapType
 
-func checkMapKeys() {
+func CheckMapKeys() {
 	for _, n := range mapqueue {
 		k := n.Type().MapType().Key
 		if !k.Broke() && !types.IsComparable(k) {
@@ -3668,7 +3679,7 @@ func typecheckdef(n ir.Node) {
 			base.ErrorfAt(n.Pos(), "xxx")
 		}
 
-		e = typecheck(e, ctxExpr)
+		e = Expr(e)
 		if e.Type() == nil {
 			goto ret
 		}
@@ -3734,12 +3745,12 @@ func typecheckdef(n ir.Node) {
 		}
 
 		if n.Name().Defn.Op() == ir.ONAME {
-			n.Name().Defn = typecheck(n.Name().Defn, ctxExpr)
+			n.Name().Defn = Expr(n.Name().Defn)
 			n.SetType(n.Name().Defn.Type())
 			break
 		}
 
-		n.Name().Defn = typecheck(n.Name().Defn, ctxStmt) // fills in n.Type
+		n.Name().Defn = Stmt(n.Name().Defn) // fills in n.Type
 
 	case ir.OTYPE:
 		n := n.(*ir.Name)
@@ -3808,7 +3819,7 @@ func checkmake(t *types.Type, arg string, np *ir.Node) bool {
 	// are the same as for index expressions. Factor the code better;
 	// for instance, indexlit might be called here and incorporate some
 	// of the bounds checks done for make.
-	n = defaultlit(n, types.Types[types.TINT])
+	n = DefaultLit(n, types.Types[types.TINT])
 	*np = n
 
 	return true
@@ -3973,8 +3984,8 @@ func isTermNode(n ir.Node) bool {
 	return false
 }
 
-// checkreturn makes sure that fn terminates appropriately.
-func checkreturn(fn *ir.Func) {
+// CheckReturn makes sure that fn terminates appropriately.
+func CheckReturn(fn *ir.Func) {
 	if fn.Type().NumResults() != 0 && len(fn.Body) != 0 {
 		markBreak(fn)
 		if !isTermNodes(fn.Body) {
@@ -4145,3 +4156,25 @@ func curpkg() *types.Pkg {
 	}
 	return fnpkg(fn.Nname)
 }
+
+func Conv(n ir.Node, t *types.Type) ir.Node {
+	if types.Identical(n.Type(), t) {
+		return n
+	}
+	n = ir.NewConvExpr(base.Pos, ir.OCONV, nil, n)
+	n.SetType(t)
+	n = Expr(n)
+	return n
+}
+
+// ConvNop converts node n to type t using the OCONVNOP op
+// and typechecks the result with ctxExpr.
+func ConvNop(n ir.Node, t *types.Type) ir.Node {
+	if types.Identical(n.Type(), t) {
+		return n
+	}
+	n = ir.NewConvExpr(base.Pos, ir.OCONVNOP, nil, n)
+	n.SetType(t)
+	n = Expr(n)
+	return n
+}
diff --git a/src/cmd/compile/internal/gc/universe.go b/src/cmd/compile/internal/typecheck/universe.go
similarity index 93%
rename from src/cmd/compile/internal/gc/universe.go
rename to src/cmd/compile/internal/typecheck/universe.go
index 5d59fdbbc5..fc8e962e28 100644
--- a/src/cmd/compile/internal/gc/universe.go
+++ b/src/cmd/compile/internal/typecheck/universe.go
@@ -2,16 +2,31 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// TODO(gri) This file should probably become part of package types.
-
-package gc
+package typecheck
 
 import (
+	"go/constant"
+
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/types"
 	"cmd/internal/src"
-	"go/constant"
+)
+
+var (
+	okfor [ir.OEND][]bool
+	iscmp [ir.OEND]bool
+)
+
+var (
+	okforeq    [types.NTYPE]bool
+	okforadd   [types.NTYPE]bool
+	okforand   [types.NTYPE]bool
+	okfornone  [types.NTYPE]bool
+	okforbool  [types.NTYPE]bool
+	okforcap   [types.NTYPE]bool
+	okforlen   [types.NTYPE]bool
+	okforarith [types.NTYPE]bool
 )
 
 var basicTypes = [...]struct {
@@ -169,7 +184,7 @@ func initUniverse() {
 	s = types.BuiltinPkg.Lookup("false")
 	s.Def = ir.NewConstAt(src.NoXPos, s, types.UntypedBool, constant.MakeBool(false))
 
-	s = lookup("_")
+	s = Lookup("_")
 	types.BlankSym = s
 	s.Block = -100
 	s.Def = NewName(s)
@@ -186,7 +201,7 @@ func initUniverse() {
 
 	types.Types[types.TNIL] = types.New(types.TNIL)
 	s = types.BuiltinPkg.Lookup("nil")
-	nnil := nodnil()
+	nnil := NodNil()
 	nnil.(*ir.NilExpr).SetSym(s)
 	s.Def = nnil
 
@@ -317,12 +332,12 @@ func makeErrorInterface() *types.Type {
 	sig := types.NewSignature(types.NoPkg, fakeRecvField(), nil, []*types.Field{
 		types.NewField(src.NoXPos, nil, types.Types[types.TSTRING]),
 	})
-	method := types.NewField(src.NoXPos, lookup("Error"), sig)
+	method := types.NewField(src.NoXPos, Lookup("Error"), sig)
 	return types.NewInterface(types.NoPkg, []*types.Field{method})
 }
 
-// finishUniverse makes the universe block visible within the current package.
-func finishUniverse() {
+// declareUniverse makes the universe block visible within the current package.
+func declareUniverse() {
 	// Operationally, this is similar to a dot import of builtinpkg, except
 	// that we silently skip symbols that are already declared in the
 	// package block rather than emitting a redeclared symbol error.
@@ -331,7 +346,7 @@ func finishUniverse() {
 		if s.Def == nil {
 			continue
 		}
-		s1 := lookup(s.Name)
+		s1 := Lookup(s.Name)
 		if s1.Def != nil {
 			continue
 		}
@@ -340,7 +355,7 @@ func finishUniverse() {
 		s1.Block = s.Block
 	}
 
-	ir.RegFP = NewName(lookup(".fp"))
+	ir.RegFP = NewName(Lookup(".fp"))
 	ir.RegFP.SetType(types.Types[types.TINT32])
 	ir.RegFP.Class_ = ir.PPARAM
 	ir.RegFP.SetUsed(true)