diff --git a/src/reflect/value.go b/src/reflect/value.go
index 025d8618a..c58d70840 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -846,7 +846,7 @@ func (v Value) MapRange() *MapIter {
 		panic(&ValueError{Method: "MapRange", Kind: v.Kind()})
 	}
 
-	keyType := v.typecode.Key().(*rawType)
+	keyType := v.typecode.key()
 	isKeyStoredAsInterface := keyType.Kind() != String && !keyType.isBinary()
 
 	return &MapIter{