cmd/compile/internal/types2: mention go.mod file when using undeclared any

Use the existing versionErrorf mechanism to report use of undeclared
any and comparable.

Also, port versionErrorf mechanism to go/types and use it in this
case as well.

Adjust tests as needed.

For #52880.

Change-Id: I6a646f16a849692ee0cb57e362d5f3d77e2c25f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/407896
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>

src/cmd/compile/internal/types2/testdata/fixedbugs/issue46090.go

@@ -8,4 +8,4 @@
 
 package p
 
-type _ comparable // ERROR undeclared
+type _ comparable // ERROR predeclared comparable

src/cmd/compile/internal/types2/testdata/fixedbugs/issue47818.go

@@ -10,13 +10,15 @@
 
 package p
 
-type T[P /* ERROR type parameter requires go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ] struct{}
+type T[P /* ERROR type parameter requires go1\.18 or later */ any /* ERROR predeclared any requires go1\.18 or later */] struct{}
 
 // for init (and main, but we're not in package main) we should only get one error
-func init[P /* ERROR func init must have no type parameters */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ]()   {}
-func main[P /* ERROR type parameter requires go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ]() {}
+func init[P /* ERROR func init must have no type parameters */ any /* ERROR predeclared any requires go1\.18 or later */]() {
+}
+func main[P /* ERROR type parameter requires go1\.18 or later */ any /* ERROR predeclared any requires go1\.18 or later */]() {
+}
 
-func f[P /* ERROR type parameter requires go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ](x P) {
+func f[P /* ERROR type parameter requires go1\.18 or later */ any /* ERROR predeclared any requires go1\.18 or later */](x P) {
 	var _ T[ /* ERROR type instantiation requires go1\.18 or later */ int]
 	var _ (T[ /* ERROR type instantiation requires go1\.18 or later */ int])
 	_ = T[ /* ERROR type instantiation requires go1\.18 or later */ int]{}
@@ -30,11 +32,11 @@ func (T[ /* ERROR type instantiation requires go1\.18 or later */ P]) g(x int) {
 }
 
 type C1 interface {
-	comparable // ERROR undeclared name: comparable \(requires version go1\.18 or later\)
+	comparable // ERROR predeclared comparable requires go1\.18 or later
 }
 
 type C2 interface {
-	comparable // ERROR undeclared name: comparable \(requires version go1\.18 or later\)
+	comparable // ERROR predeclared comparable requires go1\.18 or later
 	int        // ERROR embedding non-interface type int requires go1\.18 or later
 	~ /* ERROR embedding interface element ~int requires go1\.18 or later */ int
 	int /* ERROR embedding interface element int\|~string requires go1\.18 or later */ | ~string
@@ -47,12 +49,12 @@ type _ interface {
 }
 
 type (
-	_ comparable // ERROR undeclared name: comparable \(requires version go1\.18 or later\)
+	_ comparable // ERROR predeclared comparable requires go1\.18 or later
 	// errors for these were reported with their declaration
 	_ C1
 	_ C2
 
-	_ = comparable // ERROR undeclared name: comparable \(requires version go1\.18 or later\)
+	_ = comparable // ERROR predeclared comparable requires go1\.18 or later
 	// errors for these were reported with their declaration
 	_ = C1
 	_ = C2

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

@@ -46,7 +46,7 @@ func (check *Checker) ident(x *operand, e *syntax.Name, def *Named, wantType boo
 		return
 	case universeAny, universeComparable:
 		if !check.allowVersion(check.pkg, 1, 18) {
-			check.errorf(e, "undeclared name: %s (requires version go1.18 or later)", e.Value)
+			check.versionErrorf(e, "go1.18", "predeclared %s", e.Value)
 			return // avoid follow-on errors
 		}
 	}

src/go/types/errors.go

@@ -277,6 +277,17 @@ func (check *Checker) softErrorf(at positioner, code errorCode, format string, a
 	check.report(err)
 }
 
+func (check *Checker) versionErrorf(at positioner, code errorCode, goVersion string, format string, args ...interface{}) {
+	msg := check.sprintf(format, args...)
+	var err *error_
+	if compilerErrorMessages {
+		err = newErrorf(at, code, "%s requires %s or later (-lang was set to %s; check go.mod)", msg, goVersion, check.conf.GoVersion)
+	} else {
+		err = newErrorf(at, code, "%s requires %s or later", msg, goVersion)
+	}
+	check.report(err)
+}
+
 func (check *Checker) invalidAST(at positioner, format string, args ...any) {
 	check.errorf(at, 0, "invalid AST: "+format, args...)
 }

src/go/types/testdata/fixedbugs/issue46090.go

@@ -8,4 +8,4 @@
 
 package p
 
-type _ comparable // ERROR undeclared
+type _ comparable // ERROR predeclared comparable

src/go/types/testdata/fixedbugs/issue47818.go

@@ -10,13 +10,13 @@
 
 package p
 
-type T[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ] struct{}
+type T[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR predeclared any requires go1\.18 or later */ ] struct{}
 
 // for init (and main, but we're not in package main) we should only get one error
-func init[P /* ERROR func init must have no type parameters */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ]()   {}
-func main[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ]() {}
+func init[P /* ERROR func init must have no type parameters */ any /* ERROR predeclared any requires go1\.18 or later */ ]()   {}
+func main[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR predeclared any requires go1\.18 or later */ ]() {}
 
-func f[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ](x P) {
+func f[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR predeclared any requires go1\.18 or later */ ](x P) {
 	var _ T[ /* ERROR type instantiation requires go1\.18 or later */ int]
 	var _ (T[ /* ERROR type instantiation requires go1\.18 or later */ int])
 	_ = T[ /* ERROR type instantiation requires go1\.18 or later */ int]{}
@@ -30,11 +30,11 @@ func (T[ /* ERROR type instantiation requires go1\.18 or later */ P]) g(x int) {
 }
 
 type C1 interface {
-	comparable // ERROR undeclared name: comparable \(requires version go1\.18 or later\)
+	comparable // ERROR predeclared comparable requires go1\.18 or later
 }
 
 type C2 interface {
-	comparable // ERROR undeclared name: comparable \(requires version go1\.18 or later\)
+	comparable // ERROR predeclared comparable requires go1\.18 or later
 	int        // ERROR embedding non-interface type int requires go1\.18 or later
 	~ /* ERROR embedding interface element ~int requires go1\.18 or later */ int
 	int /* ERROR embedding interface element int\|~string requires go1\.18 or later */ | ~string
@@ -47,12 +47,12 @@ type _ interface {
 }
 
 type (
-	_ comparable // ERROR undeclared name: comparable \(requires version go1\.18 or later\)
+	_ comparable // ERROR predeclared comparable requires go1\.18 or later
 	// errors for these were reported with their declaration
 	_ C1
 	_ C2
 
-	_ = comparable // ERROR undeclared name: comparable \(requires version go1\.18 or later\)
+	_ = comparable // ERROR predeclared comparable requires go1\.18 or later
 	// errors for these were reported with their declaration
 	_ = C1
 	_ = C2

src/go/types/typexpr.go

@@ -43,7 +43,7 @@ func (check *Checker) ident(x *operand, e *ast.Ident, def *Named, wantType bool)
 		return
 	case universeAny, universeComparable:
 		if !check.allowVersion(check.pkg, 1, 18) {
-			check.errorf(e, _UndeclaredName, "undeclared name: %s (requires version go1.18 or later)", e.Name)
+			check.versionErrorf(e, _UndeclaredName, "go1.18", "predeclared %s", e.Name)
 			return // avoid follow-on errors
 		}
 	}