gc: bug306

Fixes #1040.

R=ken2
CC=golang-dev
https://golang.org/cl/2132047

src/cmd/gc/print.c

@@ -192,7 +192,7 @@ exprfmt(Fmt *f, Node *n, int prec)
 			exprfmt(f, n->left, 0);
 		} else {
 			fmtprint(f, " ");
-			if(n->left->op == OTCHAN && n->left->etype == Crecv) {
+			if(n->left->op == OTCHAN && n->left->sym == S && n->left->etype == Crecv) {
 				fmtprint(f, "(");
 				exprfmt(f, n->left, 0);
 				fmtprint(f, ")");

src/cmd/gc/subr.c

@@ -1161,7 +1161,7 @@ Tpretty(Fmt *fp, Type *t)
 		case Csend:
 			return fmtprint(fp, "chan<- %T", t->type);
 		}
-		if(t->type != T && t->type->etype == TCHAN && t->type->chan == Crecv)
+		if(t->type != T && t->type->etype == TCHAN && t->type->sym == S && t->type->chan == Crecv)
 			return fmtprint(fp, "chan (%T)", t->type);
 		return fmtprint(fp, "chan %T", t->type);
 

test/fixedbugs/bug306.dir/p1.go

+// Copyright 2010 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 p1
+
+type T <-chan int
+var x = make(chan T)
+

test/fixedbugs/bug306.dir/p2.go

+// Copyright 2010 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 p2
+
+import _ "./p1"
+

test/fixedbugs/bug306.go

+// $G $D/$F.dir/p1.go && $G $D/$F.dir/p2.go
+
+// Copyright 2010 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.
+
+ignored