gc: fix zero-length struct eval

Fixes #2232.

R=ken2
CC=golang-dev
https://golang.org/cl/4960054

1 files changed, 34 insertions, 0 deletions

diff --git a/test/struct0.go b/test/struct0.go
new file mode 100644
index 0000000000..2398c4117d
--- /dev/null
+++ b/test/struct0.go
@@ -0,0 +1,34 @@
+// $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.
+
+// zero length structs.
+// used to not be evaluated.
+// issue 2232.
+
+package main
+
+func recv(c chan interface{}) struct{} {
+	return (<-c).(struct{})
+}
+
+var m = make(map[interface{}]int)
+
+func recv1(c chan interface{}) {
+	defer rec()
+	m[(<-c).(struct{})] = 0
+}
+
+func rec() {
+	recover()
+}
+
+func main() {
+	c := make(chan interface{})
+	go recv(c)
+	c <- struct{}{}
+	go recv1(c)
+	c <- struct{}{}
+}