From c5bb50c9dcbcfe6bc9ecb178ec8fc5e71e55e04b Mon Sep 17 00:00:00 2001
From: Ken Thompson <ken@golang.org>
Date: Tue, 17 Jun 2008 18:07:40 -0700
Subject: [PATCH] assign nil to interface

SVN=123256
---
 src/cmd/6g/gen.c  |  2 +-
 src/cmd/gc/walk.c | 11 +++++------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/cmd/6g/gen.c b/src/cmd/6g/gen.c
index e1b596f1ab..b6120d7755 100644
--- a/src/cmd/6g/gen.c
+++ b/src/cmd/6g/gen.c
@@ -729,7 +729,7 @@ cgen_as(Node *nl, Node *nr, int op)
 	if(tl == T)
 		return;
 
-	if(nr == N) {
+	if(nr == N || isnil(nr)) {
 		if(isfat(tl)) {
 			/* clear a fat object */
 			if(debug['g'])
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index c40cabd8f4..16f0c2ce3e 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -43,9 +43,8 @@ loop:
 	if(n->op != ONAME)
 		dynlineno = n->lineno;	// for diagnostics
 
-	if(debug['w'] > 1 && top == Etop)
-		if(n->op != OLIST)
-			dump("walk-before", n);
+	if(debug['w'] > 1 && top == Etop && n->op != OLIST)
+		dump("walk-before", n);
 
 	t = T;
 	et = Txxx;
@@ -218,7 +217,6 @@ loop:
 
 		walktype(l, Elv);
 		walktype(r, Erv);
-
 		if(l == N || l->type == T)
 			goto ret;
 
@@ -233,6 +231,7 @@ loop:
 			}
 			goto ret;
 		}
+
 		l = ascompatee(n->op, &n->left, &n->right);
 		if(l != N)
 			*n = *reorder3(l);
@@ -662,8 +661,8 @@ badt:
 	goto ret;
 
 ret:
-	if(debug['w'] && top == Etop)
-		dump("walk-after", n);
+	if(debug['w'] && top == Etop && n != N)
+		dump("walk", n);
 
 	ullmancalc(n);
 	dynlineno = lno;