gc: more graceful errors during struct definition

Fixes #2110.

R=ken2
CC=golang-dev
https://golang.org/cl/4823060

src/cmd/gc/dcl.c

@@ -746,10 +746,8 @@ stotype(NodeList *l, int et, Type **t, int funarg)
 			} else {
 				typecheck(&n->right, Etype);
 				n->type = n->right->type;
-				if(n->type == T) {
-					*t0 = T;
-					return t0;
-				}
+				if(n->type == T)
+					continue;
 				if(left != N)
 					left->type = n->type;
 				n->right = N;

test/fixedbugs/bug365.go

+// errchk $G $D/$F.go
+
+// 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.
+
+// check that compiler doesn't stop reading struct def
+// after first unknown type.
+
+// Fixes issue 2110.
+
+package main
+
+type S struct {
+	err os.Error  // ERROR "undefined"
+	Num int
+}
+
+func main() {
+	s := S{}
+	_ = s.Num  // no error here please
+}