cmd/gc: add missing typecheck for walk-generated constants.

Fixes issue 6131.

R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://codereview.appspot.com/12800045

Committer: Russ Cox <rsc@golang.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/test/fixedbugs/issue6131.go b/test/fixedbugs/issue6131.go
new file mode 100644
index 000000000..817e4a877
--- /dev/null
+++ b/test/fixedbugs/issue6131.go
@@ -0,0 +1,20 @@
+// compile
+
+// Copyright 2013 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 6131: missing typecheck after reducing
+// n%1 == 0 to a constant value.
+
+package main
+
+func isGood(n int) bool {
+	return n%1 == 0
+}
+
+func main() {
+	if !isGood(256) {
+		panic("!isGood")
+	}
+}