diff --git a/src/lib/es6.d.ts b/src/lib/es6.d.ts
index 44e5e49f984..f5d6b06bc47 100644
--- a/src/lib/es6.d.ts
+++ b/src/lib/es6.d.ts
@@ -819,7 +819,6 @@ interface MapConstructor {
 declare var Map: MapConstructor;
 
 interface WeakMap<K, V> {
-    clear(): void;
     delete(key: K): boolean;
     get(key: K): V;
     has(key: K): boolean;
@@ -859,7 +858,6 @@ declare var Set: SetConstructor;
 
 interface WeakSet<T> {
     add(value: T): WeakSet<T>;
-    clear(): void;
     delete(value: T): boolean;
     has(value: T): boolean;
     [Symbol.toStringTag]: "WeakSet";