diff --git a/lib/utils/map.js b/lib/utils/map.js
index f6070383..a436c27c 100644
--- a/lib/utils/map.js
+++ b/lib/utils/map.js
@@ -55,8 +55,6 @@ Map.prototype.values = function values() {
  */
 
 Map.prototype.get = function get(key) {
-  if (key === '__proto__')
-    return;
   return this.map[key];
 };
 
@@ -67,8 +65,6 @@ Map.prototype.get = function get(key) {
  */
 
 Map.prototype.has = function has(key) {
-  if (key === '__proto__')
-    return false;
   return this.map[key] !== undefined;
 };
 
@@ -84,9 +80,6 @@ Map.prototype.set = function set(key, value) {
 
   assert(value !== undefined);
 
-  if (key === '__proto__')
-    return;
-
   this.map[key] = value;
 
   if (item === undefined) {