From 1d3ca9236e93c8e0ba3cd7f14b758fc2c791ad34 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9my=20Oudompheng?= <oudomphe@phare.normalesup.org>
Date: Thu, 16 Feb 2012 23:42:19 +0100
Subject: [PATCH] cmd/gc: correctly typecheck expression lists in returns.

Invalid return statements were accidentally compiling or
triggering internal errors.
Fixes #3044.

R=golang-dev, rsc
CC=golang-dev, remy
https://golang.org/cl/5673074
---
 src/cmd/gc/typecheck.c   |  5 ++++-
 test/fixedbugs/bug418.go | 22 ++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 test/fixedbugs/bug418.go

diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index b791c9e2672..5bb386d8e50 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -1410,7 +1410,10 @@ reswitch:
 
 	case ORETURN:
 		ok |= Etop;
-		typechecklist(n->list, Erv | Efnstruct);
+		if(count(n->list) == 1)
+			typechecklist(n->list, Erv | Efnstruct);
+		else
+			typechecklist(n->list, Erv);
 		if(curfn == N) {
 			yyerror("return outside function");
 			goto error;
diff --git a/test/fixedbugs/bug418.go b/test/fixedbugs/bug418.go
new file mode 100644
index 00000000000..c7b758feb3b
--- /dev/null
+++ b/test/fixedbugs/bug418.go
@@ -0,0 +1,22 @@
+// errchk $G $D/$F.go
+
+// Copyright 2012 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 3044.
+// Multiple valued expressions in return lists.
+
+package p
+
+func Two() (a, b int)
+
+// F used to compile.
+func F() (x interface{}, y int) {
+	return Two(), 0 // ERROR "single-value context"
+}
+
+// Recursive used to trigger an internal compiler error.
+func Recursive() (x interface{}, y int) {
+	return Recursive(), 0 // ERROR "single-value context"
+}