diff --git a/src/cmd/compile/internal/typecheck/dcl.go b/src/cmd/compile/internal/typecheck/dcl.go
index d1eec6d322..45e7a695ab 100644
--- a/src/cmd/compile/internal/typecheck/dcl.go
+++ b/src/cmd/compile/internal/typecheck/dcl.go
@@ -70,8 +70,6 @@ func Declare(n *ir.Name, ctxt ir.Class) {
 		n.SetFrameOffset(0)
 	}
 
-	s.Block = types.Block
-	s.Lastlineno = base.Pos
 	s.Def = n
 	n.Class = ctxt
 	if ctxt == ir.PFUNC {
diff --git a/src/cmd/compile/internal/typecheck/syms.go b/src/cmd/compile/internal/typecheck/syms.go
index ed3aaecc5a..6c2e84680b 100644
--- a/src/cmd/compile/internal/typecheck/syms.go
+++ b/src/cmd/compile/internal/typecheck/syms.go
@@ -67,7 +67,6 @@ func Lookup(name string) *types.Sym {
 // but does not make them visible to user code.
 func InitRuntime() {
 	base.Timer.Start("fe", "loadsys")
-	types.Block = 1
 
 	typs := runtimeTypes()
 	for _, d := range &runtimeDecls {
diff --git a/src/cmd/compile/internal/typecheck/universe.go b/src/cmd/compile/internal/typecheck/universe.go
index 204c31b758..a49bf5793e 100644
--- a/src/cmd/compile/internal/typecheck/universe.go
+++ b/src/cmd/compile/internal/typecheck/universe.go
@@ -91,14 +91,12 @@ func InitUniverse() {
 
 	s = Lookup("_")
 	types.BlankSym = s
-	s.Block = -100
 	s.Def = NewName(s)
 	ir.AsNode(s.Def).SetType(types.Types[types.TBLANK])
 	ir.BlankNode = ir.AsNode(s.Def)
 	ir.BlankNode.SetTypecheck(1)
 
 	s = types.BuiltinPkg.Lookup("_")
-	s.Block = -100
 	s.Def = NewName(s)
 	ir.AsNode(s.Def).SetType(types.Types[types.TBLANK])
 
@@ -222,6 +220,5 @@ func DeclareUniverse() {
 		}
 
 		s1.Def = s.Def
-		s1.Block = s.Block
 	}
 }
diff --git a/src/cmd/compile/internal/types/scope.go b/src/cmd/compile/internal/types/scope.go
index d7c454f379..e577b7aa53 100644
--- a/src/cmd/compile/internal/types/scope.go
+++ b/src/cmd/compile/internal/types/scope.go
@@ -6,21 +6,15 @@ package types
 
 import (
 	"cmd/compile/internal/base"
-	"cmd/internal/src"
 )
 
 // Declaration stack & operations
 
-var blockgen int32 = 1 // max block number
-var Block int32 = 1    // current block number
-
 // A dsym stores a symbol's shadowed declaration so that it can be
 // restored once the block scope ends.
 type dsym struct {
-	sym        *Sym // sym == nil indicates stack mark
-	def        Object
-	block      int32
-	lastlineno src.XPos // last declaration for diagnostic
+	sym *Sym // sym == nil indicates stack mark
+	def Object
 }
 
 // dclstack maintains a stack of shadowed symbol declarations so that
@@ -31,10 +25,8 @@ var dclstack []dsym
 // it can be shadowed by a new declaration within a nested block scope.
 func Pushdcl(s *Sym) {
 	dclstack = append(dclstack, dsym{
-		sym:        s,
-		def:        s.Def,
-		block:      s.Block,
-		lastlineno: s.Lastlineno,
+		sym: s,
+		def: s.Def,
 	})
 }
 
@@ -46,14 +38,11 @@ func Popdcl() {
 		s := d.sym
 		if s == nil {
 			// pop stack mark
-			Block = d.block
 			dclstack = dclstack[:i-1]
 			return
 		}
 
 		s.Def = d.def
-		s.Block = d.block
-		s.Lastlineno = d.lastlineno
 
 		// Clear dead pointer fields.
 		d.sym = nil
@@ -65,11 +54,8 @@ func Popdcl() {
 // Markdcl records the start of a new block scope for declarations.
 func Markdcl() {
 	dclstack = append(dclstack, dsym{
-		sym:   nil, // stack mark
-		block: Block,
+		sym: nil, // stack mark
 	})
-	blockgen++
-	Block = blockgen
 }
 
 func isDclstackValid() bool {
diff --git a/src/cmd/compile/internal/types/sizeof_test.go b/src/cmd/compile/internal/types/sizeof_test.go
index d37c173058..0c46077dfa 100644
--- a/src/cmd/compile/internal/types/sizeof_test.go
+++ b/src/cmd/compile/internal/types/sizeof_test.go
@@ -20,7 +20,7 @@ func TestSizeof(t *testing.T) {
 		_32bit uintptr     // size on 32bit platforms
 		_64bit uintptr     // size on 64bit platforms
 	}{
-		{Sym{}, 44, 72},
+		{Sym{}, 32, 64},
 		{Type{}, 64, 112},
 		{Map{}, 20, 40},
 		{Forward{}, 20, 32},
diff --git a/src/cmd/compile/internal/types/sym.go b/src/cmd/compile/internal/types/sym.go
index fb642f52f8..927ebc453a 100644
--- a/src/cmd/compile/internal/types/sym.go
+++ b/src/cmd/compile/internal/types/sym.go
@@ -7,7 +7,6 @@ package types
 import (
 	"cmd/compile/internal/base"
 	"cmd/internal/obj"
-	"cmd/internal/src"
 	"unicode"
 	"unicode/utf8"
 )
@@ -32,14 +31,15 @@ type Sym struct {
 	Pkg  *Pkg
 	Name string // object name
 
-	// Def, Block, and Lastlineno are saved and restored by Pushdcl/Popdcl.
-
 	// The unique ONAME, OTYPE, OPACK, or OLITERAL node that this symbol is
 	// bound to within the current scope. (Most parts of the compiler should
 	// prefer passing the Node directly, rather than relying on this field.)
-	Def        Object
-	Block      int32    // blocknumber to catch redeclaration
-	Lastlineno src.XPos // last declaration for diagnostic
+	//
+	// Def is saved and restored by Pushdcl/Popdcl.
+	//
+	// Deprecated: New code should avoid depending on Sym.Def. Add
+	// mdempsky@ as a reviewer for any CLs involving Sym.Def.
+	Def Object
 
 	flags bitset8
 }