From 86145611b0ad8c6ef6923f65f8a4fd39f07f69d7 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Mon, 23 Mar 2009 18:32:37 -0700
Subject: [PATCH] allow range on nil maps

R=ken
OCL=26663
CL=26663
---
 src/runtime/hashmap.c | 4 ++++
 test/map.go           | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/src/runtime/hashmap.c b/src/runtime/hashmap.c
index bb8dd7ba98..b3022ca149 100644
--- a/src/runtime/hashmap.c
+++ b/src/runtime/hashmap.c
@@ -870,6 +870,10 @@ sys·mapassign2(Hmap *h, ...)
 void
 sys·mapiterinit(Hmap *h, struct hash_iter *it)
 {
+	if(h == nil) {
+		it->data = nil;
+		return;
+	}
 	hash_iter_init(h, it);
 	it->data = hash_next(it);
 	if(debug) {
diff --git a/test/map.go b/test/map.go
index 085502bf52..95da48c75d 100644
--- a/test/map.go
+++ b/test/map.go
@@ -487,4 +487,10 @@ func main() {
 			fmt.Printf("update mipM[%d][%d] = %i\n", i, i, mipM[i][i]);
 		}
 	}
+	
+	// test range on nil map
+	var mnil map[string] int;
+	for x, y := range mnil {
+		panic("range mnil");
+	}
 }
-- 
2.48.1