From 85ce3c724167f82793c0c2be0edf611c70cede49 Mon Sep 17 00:00:00 2001
From: Daniel Morsing <daniel.morsing@gmail.com>
Date: Fri, 31 Aug 2012 13:02:29 -0400
Subject: [PATCH] cmd/gc: mark broken type declarations as broken.

This fixes a spurious 'invalid recursive type' error, and stops the compiler from emitting errors on uses of the invalid type.

Fixes #3766.

R=golang-dev, dave, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6443100
---
 src/cmd/gc/typecheck.c   |  1 +
 test/fixedbugs/bug451.go | 35 ++++-------------------------------
 2 files changed, 5 insertions(+), 31 deletions(-)

diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 0335fe0c32..f21f07faaa 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -2715,6 +2715,7 @@ typecheckdeftype(Node *n)
 	typecheck(&n->ntype, Etype);
 	if((t = n->ntype->type) == T) {
 		n->diag = 1;
+		n->type = T;
 		goto ret;
 	}
 	if(n->type == T) {
diff --git a/test/fixedbugs/bug451.go b/test/fixedbugs/bug451.go
index d2e4a0b44a..82182af9b9 100644
--- a/test/fixedbugs/bug451.go
+++ b/test/fixedbugs/bug451.go
@@ -1,38 +1,11 @@
-// run
+// errorcheck
 
-// Copyright 2012 The Go Authors.  All rights reserved.
+// 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 3835: 8g tries to optimize arithmetic involving integer
-// constants, but can run out of registers in the process.
-
 package main
 
-var a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, A, B, C, D, E, F, G int
-
-func foo() int {
-	return a + 1 + b + 2 + c + 3 + d + 4 + e + 5 + f + 6 + g + 7 + h + 8 + i + 9 + j + 10 +
-		k + 1 + l + 2 + m + 3 + n + 4 + o + 5 + p + 6 + q + 7 + r + 8 + s + 9 + t + 10 +
-		u + 1 + v + 2 + w + 3 + x + 4 + y + 5 + z + 6 + A + 7 + B + 8 + C + 9 + D + 10 +
-		E + 1 + F + 2 + G + 3
-}
-
-func bar() int8 {
-	var (
-		W int16
-		X int32
-		Y int32
-		Z int32
-	)
-	return int8(W+int16(X+3)+3) * int8(Y+3+Z*3)
-}
+type T x.T // ERROR "undefined"
 
-func main() {
-	if foo() == 0 {
-		panic("foo")
-	}
-	if bar() == 0 {
-		panic("bar")
-	}
-}
+// bogus "invalid recursive type"
-- 
2.48.1