cmd/gc: fix wrong interaction between inlining and embedded builtins.

The patch makes the compile user an ordinary package-local
symbol for the name of embedded fields of builtin type.

This is incompatible with the fix delivered for issue 2687
(revision 3c060add43fb) but fixes it in a different way, because
the explicit symbol on the field makes the typechecker able to
find it in lookdot.

Fixes #3552.

R=lvd, rsc, daniel.morsing
CC=golang-dev
https://golang.org/cl/6866047

src/cmd/gc/dcl.c

@@ -1013,6 +1013,9 @@ embedded(Sym *s)
 
 	if(exportname(name))
 		n = newname(lookup(name));
+	else if(s->pkg == builtinpkg && importpkg != nil)
+		// The name of embedded builtins during imports belongs to importpkg.
+		n = newname(pkglookup(name, importpkg));
 	else
 		n = newname(pkglookup(name, s->pkg));
 	n = nod(ODCLFIELD, n, oldname(s));

src/cmd/gc/fmt.c

@@ -1082,7 +1082,6 @@ exprfmt(Fmt *f, Node *n, int prec)
 {
 	int nprec;
 	NodeList *l;
-	Type *t;
 
 	while(n && n->implicit && (n->op == OIND || n->op == OADDR))
 		n = n->left;
@@ -1208,14 +1207,6 @@ exprfmt(Fmt *f, Node *n, int prec)
 			else
 				fmtprint(f, "(%T{", n->type);
 			for(l=n->list; l; l=l->next) {
-				// another special case: if n->left is an embedded field of builtin type,
-				// it needs to be non-qualified.  Can't figure that out in %S, so do it here
-				if(l->n->left->type->embedded) {
-					t = l->n->left->type->type;
-					if(t->sym == S)
-						t = t->type;
-					fmtprint(f, " %hhS:%N", t->sym, l->n->right);
-				} else
 				fmtprint(f, " %hhS:%N", l->n->left->sym, l->n->right);
 
 				if(l->next)

test/bugs/bug434.go → test/fixedbugs/issue3552.go

-// $G $D/$F.dir/one.go && $G $D/$F.dir/two.go || echo BUG:bug434
-
-// NOTE: This test is not run by 'run.go' and so not run by all.bash.
-// To run this test you must use the ./run shell script.
+// compiledir
 
 // Copyright 2011 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.
 
+// Issue 3552: cross-package inlining misbehaves when
+// referencing embedded builtins.
+
 package ignored

test/run.go

@@ -710,5 +710,4 @@ var skipOkay = map[string]bool{
 	"fixedbugs/bug385_64.go": true, // arch-specific errors.
 	"fixedbugs/bug429.go":    true,
 	"bugs/bug395.go":         true,
-	"bugs/bug434.go":          true,
 }