From: Rémy Oudompheng <oudomphe@phare.normalesup.org>
Date: Wed, 7 Nov 2012 22:09:01 +0000 (+0100)
Subject: cmd/gc: fix internal compiler error with broken structs.
X-Git-Tag: go1.1rc2~1929
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c208a3a263648a5f2a363b3af801a9d1522be03b;p=gostls13.git

cmd/gc: fix internal compiler error with broken structs.

Fixes #4359.

R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6834043
---

diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 35c99c858c..9b42772393 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -443,7 +443,7 @@ reswitch:
 		ok |= Etype;
 		n->op = OTYPE;
 		n->type = tostruct(n->list);
-		if(n->type == T)
+		if(n->type == T || n->type->broke)
 			goto error;
 		n->list = nil;
 		break;
diff --git a/test/fixedbugs/issue4359.go b/test/fixedbugs/issue4359.go
new file mode 100644
index 0000000000..b5adb4010b
--- /dev/null
+++ b/test/fixedbugs/issue4359.go
@@ -0,0 +1,19 @@
+// errorcheck
+
+// 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 4359: wrong handling of broken struct fields
+// causes "internal compiler error: lookdot badwidth".
+
+package main
+
+type T struct {
+	x T1 // ERROR "undefined"
+}
+
+func f() {
+	var t *T
+	_ = t.x
+}