gc: top-level closure bug

Fixes #2055.

R=ken2
CC=golang-dev
https://golang.org/cl/4816059
diff --git a/test/fixedbugs/bug355.go b/test/fixedbugs/bug355.go
new file mode 100644
index 0000000..a9cf016
--- /dev/null
+++ b/test/fixedbugs/bug355.go
@@ -0,0 +1,18 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// 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.
+
+package main
+
+var f = func() int {
+	type S int
+	return 42
+}
+
+func main() {
+	if f() != 42 {
+		panic("BUG: bug355")
+	}
+}