cmd/compile/internal/types2: use compiler version error when configured for compiler

Fixes #49368.

Change-Id: I7c7575ae8bb6271160747e3f1888b144c3ab24c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/361411
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>

src/cmd/compile/internal/types2/builtins.go

@@ -574,7 +574,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 	case _Add:
 		// unsafe.Add(ptr unsafe.Pointer, len IntegerType) unsafe.Pointer
 		if !check.allowVersion(check.pkg, 1, 17) {
-			check.error(call.Fun, "unsafe.Add requires go1.17 or later")
+			check.versionErrorf(call.Fun, "go1.17", "unsafe.Add")
 			return
 		}
 
@@ -700,7 +700,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 	case _Slice:
 		// unsafe.Slice(ptr *T, len IntegerType) []T
 		if !check.allowVersion(check.pkg, 1, 17) {
-			check.error(call.Fun, "unsafe.Slice requires go1.17 or later")
+			check.versionErrorf(call.Fun, "go1.17", "unsafe.Slice")
 			return
 		}
 

src/cmd/compile/internal/types2/call.go

@@ -16,7 +16,7 @@ import (
 // The operand x must be the evaluation of inst.X and its type must be a signature.
 func (check *Checker) funcInst(x *operand, inst *syntax.IndexExpr) {
 	if !check.allowVersion(check.pkg, 1, 18) {
-		check.softErrorf(inst.Pos(), "function instantiation requires go1.18 or later")
+		check.versionErrorf(inst.Pos(), "go1.18", "function instantiation")
 	}
 
 	xlist := unpackExpr(inst.Index)
@@ -363,9 +363,9 @@ func (check *Checker) arguments(call *syntax.CallExpr, sig *Signature, targs []T
 	if sig.TypeParams().Len() > 0 {
 		if !check.allowVersion(check.pkg, 1, 18) {
 			if iexpr, _ := call.Fun.(*syntax.IndexExpr); iexpr != nil {
-				check.softErrorf(iexpr.Pos(), "function instantiation requires go1.18 or later")
+				check.versionErrorf(iexpr.Pos(), "go1.18", "function instantiation")
 			} else {
-				check.softErrorf(call.Pos(), "implicit function instantiation requires go1.18 or later")
+				check.versionErrorf(call.Pos(), "go1.18", "implicit function instantiation")
 			}
 		}
 		// TODO(gri) provide position information for targs so we can feed

src/cmd/compile/internal/types2/conversions.go

@@ -7,6 +7,7 @@
 package types2
 
 import (
+	"fmt"
 	"go/constant"
 	"unicode"
 )
@@ -181,11 +182,9 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 					}
 					// check != nil
 					if cause != nil {
+						*cause = "conversion of slices to array pointers requires go1.17 or later"
 						if check.conf.CompilerErrorMessages {
-							// compiler error message assumes a -lang flag
+							*cause += fmt.Sprintf(" (-lang was set to %s; check go.mod)", check.conf.GoVersion)
-							*cause = "conversion of slices to array pointers only supported as of -lang=go1.17"
-						} else {
-							*cause = "conversion of slices to array pointers requires go1.17 or later"
 						}
 					}
 					return false

src/cmd/compile/internal/types2/decl.go

@@ -555,7 +555,7 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *Named
 		check.validType(obj.typ, nil)
 		// If typ is local, an error was already reported where typ is specified/defined.
 		if check.isImportedConstraint(rhs) && !check.allowVersion(check.pkg, 1, 18) {
-			check.errorf(tdecl.Type.Pos(), "using type constraint %s requires go1.18 or later", rhs)
+			check.versionErrorf(tdecl.Type.Pos(), "go1.18", "using type constraint %s", rhs)
 		}
 	}).describef(obj, "validType(%s)", obj.Name())
 
@@ -570,11 +570,7 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *Named
 	// alias declaration
 	if alias {
 		if !check.allowVersion(check.pkg, 1, 9) {
-			if check.conf.CompilerErrorMessages {
+			check.versionErrorf(tdecl, "go1.9", "type aliases")
-				check.error(tdecl, "type aliases only supported as of -lang=go1.9")
-			} else {
-				check.error(tdecl, "type aliases requires go1.9 or later")
-			}
 		}
 
 		obj.typ = Typ[Invalid]

src/cmd/compile/internal/types2/errors.go

@@ -230,6 +230,16 @@ func (check *Checker) softErrorf(at poser, format string, args ...interface{}) {
 	check.err(at, check.sprintf(format, args...), true)
 }
 
+func (check *Checker) versionErrorf(at poser, goVersion string, format string, args ...interface{}) {
+	msg := check.sprintf(format, args...)
+	if check.conf.CompilerErrorMessages {
+		msg = fmt.Sprintf("%s requires %s or later (-lang was set to %s; check go.mod)", msg, goVersion, check.conf.GoVersion)
+	} else {
+		msg = fmt.Sprintf("%s requires %s or later", msg, goVersion)
+	}
+	check.err(at, msg, true)
+}
+
 // posFor reports the left (= start) position of at.
 func posFor(at poser) syntax.Pos {
 	switch x := at.(type) {

src/cmd/compile/internal/types2/expr.go

@@ -869,7 +869,7 @@ func (check *Checker) shift(x, y *operand, e syntax.Expr, op syntax.Operator) {
 		x.mode = invalid
 		return
 	} else if !allUnsigned(y.typ) && !check.allowVersion(check.pkg, 1, 13) {
-		check.errorf(y, invalidOp+"signed shift count %s requires go1.13 or later", y)
+		check.versionErrorf(y, "go1.13", invalidOp+"signed shift count %s", y)
 		x.mode = invalid
 		return
 	}

src/cmd/compile/internal/types2/typeset.go

@@ -271,7 +271,7 @@ func computeInterfaceTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *_
 			tset := computeInterfaceTypeSet(check, pos, u)
 			// If typ is local, an error was already reported where typ is specified/defined.
 			if check != nil && check.isImportedConstraint(typ) && !check.allowVersion(check.pkg, 1, 18) {
-				check.errorf(pos, "embedding constraint interface %s requires go1.18 or later", typ)
+				check.versionErrorf(pos, "go1.18", "embedding constraint interface %s", typ)
 				continue
 			}
 			if tset.comparable {
@@ -283,7 +283,7 @@ func computeInterfaceTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *_
 			terms = tset.terms
 		case *Union:
 			if check != nil && !check.allowVersion(check.pkg, 1, 18) {
-				check.errorf(pos, "embedding interface element %s requires go1.18 or later", u)
+				check.versionErrorf(pos, "go1.18", "embedding interface element %s", u)
 				continue
 			}
 			tset := computeUnionTypeSet(check, pos, u)
@@ -300,7 +300,7 @@ func computeInterfaceTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *_
 				continue
 			}
 			if check != nil && !check.allowVersion(check.pkg, 1, 18) {
-				check.errorf(pos, "embedding non-interface type %s requires go1.18 or later", typ)
+				check.versionErrorf(pos, "go1.18", "embedding non-interface type %s", typ)
 				continue
 			}
 			terms = termlist{{false, typ}}

src/cmd/compile/internal/types2/typexpr.go

@@ -264,7 +264,7 @@ func (check *Checker) typInternal(e0 syntax.Expr, def *Named) (T Type) {
 
 	case *syntax.IndexExpr:
 		if !check.allowVersion(check.pkg, 1, 18) {
-			check.softErrorf(e.Pos(), "type instantiation requires go1.18 or later")
+			check.versionErrorf(e.Pos(), "go1.18", "type instantiation")
 		}
 		return check.instantiatedType(e.X, unpackExpr(e.Index), def)
 

src/cmd/compile/internal/types2/version.go

@@ -21,7 +21,7 @@ func (check *Checker) langCompat(lit *syntax.BasicLit) {
 	}
 	// len(s) > 2
 	if strings.Contains(s, "_") {
-		check.error(lit, "underscores in numeric literals requires go1.13 or later")
+		check.versionErrorf(lit, "go1.13", "underscores in numeric literals")
 		return
 	}
 	if s[0] != '0' {
@@ -29,15 +29,15 @@ func (check *Checker) langCompat(lit *syntax.BasicLit) {
 	}
 	radix := s[1]
 	if radix == 'b' || radix == 'B' {
-		check.error(lit, "binary literals requires go1.13 or later")
+		check.versionErrorf(lit, "go1.13", "binary literals")
 		return
 	}
 	if radix == 'o' || radix == 'O' {
-		check.error(lit, "0o/0O-style octal literals requires go1.13 or later")
+		check.versionErrorf(lit, "go1.13", "0o/0O-style octal literals")
 		return
 	}
 	if lit.Kind != syntax.IntLit && (radix == 'x' || radix == 'X') {
-		check.error(lit, "hexadecimal floating-point literals requires go1.13 or later")
+		check.versionErrorf(lit, "go1.13", "hexadecimal floating-point literals")
 	}
 }
 

src/cmd/go/testdata/script/mod_edit_go.txt

@@ -2,7 +2,7 @@
 
 env GO111MODULE=on
 ! go build
-stderr 'type aliases only supported as of'
+stderr ' type aliases requires'
 go mod edit -go=1.9
 grep 'go 1.9' go.mod
 go build
@@ -11,7 +11,7 @@ go build
 # the cached 1.9 build. (https://golang.org/issue/37804)
 go mod edit -go=1.8
 ! go build
-stderr 'type aliases only supported as of'
+stderr 'type aliases requires'
 
 
 -- go.mod --

test/fixedbugs/issue49368.go

@@ -0,0 +1,11 @@
+// errorcheck -lang=go1.17
+
+// Copyright 2021 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 p
+
+type _ interface {
+	int // ERROR "embedding non-interface type int requires go1\.18 or later \(-lang was set to go1\.17; check go.mod\)"
+}