diff --git a/lib/lib.core.es6.d.ts b/lib/lib.core.es6.d.ts
index 6d6a68559f8..fd115497f8a 100644
--- a/lib/lib.core.es6.d.ts
+++ b/lib/lib.core.es6.d.ts
@@ -3965,34 +3965,7 @@ interface ObjectConstructor {
       * Copy the values of all of the enumerable own properties from one or more source objects to a 
       * target object. Returns the target object.
       * @param target The target object to copy to.
-      * @param source The source object from which to copy properties.
-      */
-    assign<T, U>(target: T, source: U): T & U;
-
-    /**
-      * Copy the values of all of the enumerable own properties from one or more source objects to a 
-      * target object. Returns the target object.
-      * @param target The target object to copy to.
-      * @param source1 The first source object from which to copy properties.
-      * @param source2 The second source object from which to copy properties.
-      */
-    assign<T, U, V>(target: T, source1: U, source2: V): T & U & V;
-
-    /**
-      * Copy the values of all of the enumerable own properties from one or more source objects to a 
-      * target object. Returns the target object.
-      * @param target The target object to copy to.
-      * @param source1 The first source object from which to copy properties.
-      * @param source2 The second source object from which to copy properties.
-      * @param source3 The third source object from which to copy properties.
-      */
-    assign<T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W;
-
-    /**
-      * Copy the values of all of the enumerable own properties from one or more source objects to a 
-      * target object. Returns the target object.
-      * @param target The target object to copy to.
-      * @param sources One or more source objects from which to copy properties
+      * @param sources One or more source objects to copy properties from.
       */
     assign(target: any, ...sources: any[]): any;
 
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 4cdca78aa71..47662c26b42 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -2864,6 +2864,13 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                     }
                     else {
                         emit(node.left);
+                        // Add indentation before emit the operator if the operator is on different line
+                        // For example:
+                        //      3
+                        //      + 2;
+                        //   emitted as
+                        //      3
+                        //          + 2;
                         let indentedBeforeOperator = indentIfOnDifferentLines(node, node.left, node.operatorToken, node.operatorToken.kind !== SyntaxKind.CommaToken ? " " : undefined);
                         write(tokenToString(node.operatorToken.kind));
                         let indentedAfterOperator = indentIfOnDifferentLines(node, node.operatorToken, node.right, " ");