diff --git a/src/lib/es6.d.ts b/src/lib/es6.d.ts
index 50238e94bb4f9..3e6ac3f756ce6 100644
--- a/src/lib/es6.d.ts
+++ b/src/lib/es6.d.ts
@@ -230,22 +230,22 @@ interface ArrayLike<T> {
 
 interface Array<T> {
     /** Iterator */
-    [Symbol.iterator] (): Iterator<T>;
+    [Symbol.iterator](): IterableIterator<T>;
 
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, T]>;
+    entries(): IterableIterator<[number, T]>;
 
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<T>;
+    values(): IterableIterator<T>;
 
     /** 
       * Returns the value of the first element in the array where predicate is true, and undefined 
@@ -329,7 +329,7 @@ interface ArrayConstructor {
 
 interface String {
     /** Iterator */
-    [Symbol.iterator] (): Iterator<string>;
+    [Symbol.iterator](): IterableIterator<string>;
 
     /**
       * Returns a nonnegative integer Number less than 1114112 (0x110000) that is the code point 
@@ -447,14 +447,19 @@ interface IteratorResult<T> {
 }
 
 interface Iterator<T> {
-    [Symbol.iterator](): Iterator<T>;
     next(): IteratorResult<T>;
+    return?(value?: any): IteratorResult<T>;
+    throw?(e?: any): IteratorResult<T>;
 }
 
 interface Iterable<T> {
     [Symbol.iterator](): Iterator<T>;
 }
 
+interface IterableIterator<T> extends Iterator<T> {
+    [Symbol.iterator](): IterableIterator<T>;
+}
+
 interface GeneratorFunction extends Function {
 
 }
@@ -470,10 +475,11 @@ interface GeneratorFunctionConstructor {
 }
 declare var GeneratorFunction: GeneratorFunctionConstructor;
 
-interface Generator<T> extends Iterator<T> {
+interface Generator<T> extends IterableIterator<T> {
     next(value?: any): IteratorResult<T>;
-    throw (exception: any): IteratorResult<T>;
-    return (value: T): IteratorResult<T>;
+    throw(exception: any): IteratorResult<T>;
+    return(value: T): IteratorResult<T>;
+    [Symbol.iterator](): Generator<T>;
     [Symbol.toStringTag]: string;
 }
 
@@ -641,15 +647,15 @@ interface RegExp {
 interface Map<K, V> {
     clear(): void;
     delete(key: K): boolean;
-    entries(): Iterator<[K, V]>;
+    entries(): IterableIterator<[K, V]>;
     forEach(callbackfn: (value: V, index: K, map: Map<K, V>) => void, thisArg?: any): void;
     get(key: K): V;
     has(key: K): boolean;
-    keys(): Iterator<K>;
+    keys(): IterableIterator<K>;
     set(key: K, value?: V): Map<K, V>;
     size: number;
-    values(): Iterator<V>;
-    [Symbol.iterator]():Iterator<[K,V]>;
+    values(): IterableIterator<V>;
+    [Symbol.iterator]():IterableIterator<[K,V]>;
     [Symbol.toStringTag]: string;
 }
 
@@ -680,13 +686,13 @@ interface Set<T> {
     add(value: T): Set<T>;
     clear(): void;
     delete(value: T): boolean;
-    entries(): Iterator<[T, T]>;
+    entries(): IterableIterator<[T, T]>;
     forEach(callbackfn: (value: T, index: T, set: Set<T>) => void, thisArg?: any): void;
     has(value: T): boolean;
-    keys(): Iterator<T>;
+    keys(): IterableIterator<T>;
     size: number;
-    values(): Iterator<T>;
-    [Symbol.iterator]():Iterator<T>;
+    values(): IterableIterator<T>;
+    [Symbol.iterator]():IterableIterator<T>;
     [Symbol.toStringTag]: string;
 }
 
@@ -917,7 +923,7 @@ interface Int8Array {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -997,7 +1003,7 @@ interface Int8Array {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -1134,10 +1140,10 @@ interface Int8Array {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Int8ArrayConstructor {
@@ -1207,7 +1213,7 @@ interface Uint8Array {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -1287,7 +1293,7 @@ interface Uint8Array {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -1424,10 +1430,10 @@ interface Uint8Array {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Uint8ArrayConstructor {
@@ -1497,7 +1503,7 @@ interface Uint8ClampedArray {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -1577,7 +1583,7 @@ interface Uint8ClampedArray {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -1714,10 +1720,10 @@ interface Uint8ClampedArray {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Uint8ClampedArrayConstructor {
@@ -1787,7 +1793,7 @@ interface Int16Array {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -1867,7 +1873,7 @@ interface Int16Array {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -2004,10 +2010,10 @@ interface Int16Array {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Int16ArrayConstructor {
@@ -2077,7 +2083,7 @@ interface Uint16Array {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -2157,7 +2163,7 @@ interface Uint16Array {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -2294,10 +2300,10 @@ interface Uint16Array {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Uint16ArrayConstructor {
@@ -2367,7 +2373,7 @@ interface Int32Array {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -2447,7 +2453,7 @@ interface Int32Array {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -2584,10 +2590,10 @@ interface Int32Array {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Int32ArrayConstructor {
@@ -2657,7 +2663,7 @@ interface Uint32Array {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -2737,7 +2743,7 @@ interface Uint32Array {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -2874,10 +2880,10 @@ interface Uint32Array {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Uint32ArrayConstructor {
@@ -2947,7 +2953,7 @@ interface Float32Array {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -3027,7 +3033,7 @@ interface Float32Array {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -3164,10 +3170,10 @@ interface Float32Array {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Float32ArrayConstructor {
@@ -3237,7 +3243,7 @@ interface Float64Array {
     /** 
       * Returns an array of key, value pairs for every entry in the array
       */
-    entries(): Iterator<[number, number]>;
+    entries(): IterableIterator<[number, number]>;
 
     /**
       * Determines whether all the members of an array satisfy the specified test.
@@ -3317,7 +3323,7 @@ interface Float64Array {
     /** 
       * Returns an list of keys in the array
       */
-    keys(): Iterator<number>;
+    keys(): IterableIterator<number>;
 
     /**
       * Returns the index of the last occurrence of a value in an array.
@@ -3454,10 +3460,10 @@ interface Float64Array {
     /** 
       * Returns an list of values in the array
       */
-    values(): Iterator<number>;
+    values(): IterableIterator<number>;
 
     [index: number]: number;
-    [Symbol.iterator] (): Iterator<number>;
+    [Symbol.iterator](): IterableIterator<number>;
 }
 
 interface Float64ArrayConstructor {
@@ -3516,7 +3522,7 @@ declare var Reflect: {
     construct(target: Function, argumentsList: ArrayLike<any>): any;
     defineProperty(target: any, propertyKey: PropertyKey, attributes: PropertyDescriptor): boolean;
     deleteProperty(target: any, propertyKey: PropertyKey): boolean;
-    enumerate(target: any): Iterator<any>;
+    enumerate(target: any): IterableIterator<any>;
     get(target: any, propertyKey: PropertyKey, receiver?: any): any;
     getOwnPropertyDescriptor(target: any, propertyKey: PropertyKey): PropertyDescriptor;
     getPrototypeOf(target: any): any;