From 6e0b39e39976a59d9df2bfceffbb90ec76032707 Mon Sep 17 00:00:00 2001
From: Ron Buckton <ron.buckton@microsoft.com>
Date: Tue, 23 Apr 2019 21:27:06 -0500
Subject: [PATCH] Update src/compiler/visitor.ts

Co-Authored-By: Kingwl <kingwenlu@gmail.com>
---
 src/compiler/visitor.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 16880972b69..c5cb3f87fc5 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -269,7 +269,7 @@ namespace ts {
                     nodesVisitor((<PropertyDeclaration>node).modifiers, visitor, isModifier),
                     visitNode((<PropertyDeclaration>node).name, visitor, isPropertyName),
                     // QuestionToken and ExclamationToken is uniqued in Property Declaration and the signature of 'updateProperty' is that too
-                    (visitNode((<PropertyDeclaration>node).questionToken, tokenVisitor, isToken), visitNode((<PropertyDeclaration>node).exclamationToken, tokenVisitor, isToken)),
+                    visitNode((<PropertyDeclaration>node).questionToken || (<PropertyDeclaration>node).exclamationToken, tokenVisitor, isToken),
                     visitNode((<PropertyDeclaration>node).type, visitor, isTypeNode),
                     visitNode((<PropertyDeclaration>node).initializer, visitor, isExpression));