From 53372903c70e93704cc32dc229d8d83a03bcc457 Mon Sep 17 00:00:00 2001
From: Rob Pike <r@golang.org>
Date: Mon, 23 Apr 2012 12:07:02 +1000
Subject: [PATCH] reflect: document and test TypeOf(nil) Fixes #3549.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/6107047
---
 src/pkg/reflect/all_test.go | 5 +++++
 src/pkg/reflect/type.go     | 1 +
 2 files changed, 6 insertions(+)

diff --git a/src/pkg/reflect/all_test.go b/src/pkg/reflect/all_test.go
index 6bb0613981..e331405635 100644
--- a/src/pkg/reflect/all_test.go
+++ b/src/pkg/reflect/all_test.go
@@ -638,6 +638,7 @@ var (
 
 var deepEqualTests = []DeepEqualTest{
 	// Equalities
+	{nil, nil, true},
 	{1, 1, true},
 	{int32(1), int32(1), true},
 	{0.5, 0.5, true},
@@ -696,6 +697,10 @@ func TestDeepEqual(t *testing.T) {
 }
 
 func TestTypeOf(t *testing.T) {
+	// Special case for nil
+	if typ := TypeOf(nil); typ != nil {
+		t.Errorf("expected nil type for nil value; got %v", typ)
+	}
 	for _, test := range deepEqualTests {
 		v := ValueOf(test.a)
 		if !v.IsValid() {
diff --git a/src/pkg/reflect/type.go b/src/pkg/reflect/type.go
index 64550b8f6c..060bde3aff 100644
--- a/src/pkg/reflect/type.go
+++ b/src/pkg/reflect/type.go
@@ -940,6 +940,7 @@ func toType(p *runtimeType) Type {
 }
 
 // TypeOf returns the reflection Type of the value in the interface{}.
+// TypeOf(nil) returns nil.
 func TypeOf(i interface{}) Type {
 	eface := *(*emptyInterface)(unsafe.Pointer(&i))
 	return toType(eface.typ)