go/types, types2: improve error message for init without body

Change-Id: I8a684965e88e0e33a6ff33a16e08d136e3267f7e
Reviewed-on: https://go-review.googlesource.com/c/go/+/663636
TryBot-Bypass: Mark Freeman <mark@golang.org>
Auto-Submit: Mark Freeman <mark@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>

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

@@ -436,10 +436,8 @@ func (check *Checker) collectObjects() {
 					if name == "init" {
 						obj.parent = pkg.scope
 						check.recordDef(s.Name, obj)
-						// init functions must have a body
 						if s.Body == nil {
-							// TODO(gri) make this error message consistent with the others above
-							check.softErrorf(obj.pos, MissingInitBody, "missing function body")
+							check.softErrorf(obj.pos, MissingInitBody, "func init must have a body")
 						}
 					} else {
 						check.declare(pkg.scope, s.Name, obj, nopos)

src/go/internal/srcimporter/srcimporter_test.go

@@ -192,7 +192,7 @@ func TestIssue20855(t *testing.T) {
 	testenv.MustHaveSource(t)
 
 	pkg, err := importer.ImportFrom("go/internal/srcimporter/testdata/issue20855", ".", 0)
-	if err == nil || !strings.Contains(err.Error(), "missing function body") {
+	if err == nil || !strings.Contains(err.Error(), "func init must have a body") {
 		t.Fatalf("got unexpected or no error: %v", err)
 	}
 	if pkg == nil {

src/go/internal/srcimporter/testdata/issue20855/issue20855.go

@@ -4,4 +4,4 @@
 
 package issue20855
 
-func init() // "missing function body" is a soft error
+func init() // "func init must have a body" is a soft error

src/go/types/resolver.go

@@ -425,10 +425,8 @@ func (check *Checker) collectObjects() {
 						// don't declare init functions in the package scope - they are invisible
 						obj.parent = pkg.scope
 						check.recordDef(d.decl.Name, obj)
-						// init functions must have a body
 						if d.decl.Body == nil {
-							// TODO(gri) make this error message consistent with the others above
-							check.softErrorf(obj, MissingInitBody, "missing function body")
+							check.softErrorf(obj, MissingInitBody, "func init must have a body")
 						}
 					} else {
 						check.declare(pkg.scope, d.decl.Name, obj, nopos)

src/internal/types/testdata/check/decls0.go

@@ -43,7 +43,7 @@ type init /* ERROR "cannot declare init" */ struct{}
 var _, init /* ERROR "cannot declare init" */ int
 
 func init() {}
-func init /* ERROR "missing function body" */ ()
+func init /* ERROR "func init must have a body" */ ()
 
 func _() { const init = 0 }
 func _() { type init int }

test/fixedbugs/issue3705.go

@@ -6,4 +6,4 @@
 
 package p
 
-func init() // ERROR "missing function body|cannot declare init"
+func init() // ERROR "func init must have a body|cannot declare init"