From 524b7c9954303353b7108a60e87455e70e2c00ed Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Fri, 14 Sep 2018 10:47:29 -0700
Subject: [PATCH] Fix resulting issues in compiler

---
 src/services/utilities.ts | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 40a9936b605..926e50b1e96 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -1648,17 +1648,21 @@ namespace ts {
      * WARNING: This is an expensive operation and is only intended to be used in refactorings
      * and code fixes (because those are triggered by explicit user actions).
      */
-    export function getSynthesizedDeepClone<T extends Node | undefined>(node: T, includeTrivia = true): T {
+    export function getSynthesizedDeepClone<T extends Node>(node: T, includeTrivia?: boolean): T;
+    export function getSynthesizedDeepClone<T extends Node>(node: T | undefined, includeTrivia?: boolean): T | undefined;
+    export function getSynthesizedDeepClone<T extends Node>(node: T | undefined, includeTrivia = true): T | undefined {
         const clone = node && getSynthesizedDeepCloneWorker(node as NonNullable<T>);
         if (clone && !includeTrivia) suppressLeadingAndTrailingTrivia(clone);
         return clone;
     }
 
-    export function getSynthesizedDeepCloneWithRenames<T extends Node | undefined>(node: T, includeTrivia = true, renameMap?: Map<Identifier>, checker?: TypeChecker, callback?: (originalNode: Node, clone: Node) => any): T {
+    export function getSynthesizedDeepCloneWithRenames<T extends Node>(node: T, includeTrivia?: boolean, renameMap?: Map<Identifier>, checker?: TypeChecker, callback?: (originalNode: Node, clone: Node) => any): T;
+    export function getSynthesizedDeepCloneWithRenames<T extends Node>(node: T | undefined, includeTrivia?: boolean, renameMap?: Map<Identifier>, checker?: TypeChecker, callback?: (originalNode: Node, clone: Node) => any): T | undefined;
+    export function getSynthesizedDeepCloneWithRenames<T extends Node>(node: T | undefined, includeTrivia = true, renameMap?: Map<Identifier>, checker?: TypeChecker, callback?: (originalNode: Node, clone: Node) => any): T | undefined {
 
         let clone;
-        if (node && isIdentifier(node!) && renameMap && checker) {
-            const symbol = checker.getSymbolAtLocation(node!);
+        if (node && isIdentifier(node) && renameMap && checker) {
+            const symbol = checker.getSymbolAtLocation(node);
             const renameInfo = symbol && renameMap.get(String(getSymbolId(symbol)));
 
             if (renameInfo) {
@@ -1667,11 +1671,11 @@ namespace ts {
         }
 
         if (!clone) {
-            clone = node && getSynthesizedDeepCloneWorker(node as NonNullable<T>, renameMap, checker, callback);
+            clone = node && getSynthesizedDeepCloneWorker(node, renameMap, checker, callback);
         }
 
         if (clone && !includeTrivia) suppressLeadingAndTrailingTrivia(clone);
-        if (callback && node) callback(node!, clone);
+        if (callback && node && clone) callback(node, clone);
 
         return clone as T;
     }