cmd/gc: fix segfault in isgoconst.

Variables declared with 'var' have no sym->def.

Fixes #7794.

LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/88360043

diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index 28d0725d33d948f991bd42b37eaf92b7ba738ddf..f356c4f59a3edf4a961fe27e122810ad3334d054 100644 (file)
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -1594,7 +1594,7 @@ isgoconst(Node *n)
 
        case ONAME:
                l = n->sym->def;
-               if(l->op == OLITERAL && n->val.ctype != CTNIL)
+               if(l && l->op == OLITERAL && n->val.ctype != CTNIL)
                        return 1;
                break;
        

diff --git a/test/fixedbugs/issue7794.go b/test/fixedbugs/issue7794.go
new file mode 100644 (file)
index 0000000..1e303bd
--- /dev/null
+++ b/test/fixedbugs/issue7794.go
@@ -0,0 +1,12 @@
+// compile
+
+// Copyright 2014 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
+
+func main() {
+       var a [10]int
+       const ca = len(a)
+}