diff --git a/src/compiler/visitor.ts b/src/compiler/visitor.ts
index 0d4d0d9482d..0cb3b269105 100644
--- a/src/compiler/visitor.ts
+++ b/src/compiler/visitor.ts
@@ -268,7 +268,8 @@ namespace ts {
                     nodesVisitor((<PropertyDeclaration>node).decorators, visitor, isDecorator),
                     nodesVisitor((<PropertyDeclaration>node).modifiers, visitor, isModifier),
                     visitNode((<PropertyDeclaration>node).name, visitor, isPropertyName),
-                    visitNode((<PropertyDeclaration>node).questionToken, tokenVisitor, isToken),
+                    // QuestionToken and ExclamationToken is uniqued in Property Declaration and the signature of 'updateProperty' is that too
+                    visitNode((<PropertyDeclaration>node).questionToken || (<PropertyDeclaration>node).exclamationToken, tokenVisitor, isToken),
                     visitNode((<PropertyDeclaration>node).type, visitor, isTypeNode),
                     visitNode((<PropertyDeclaration>node).initializer, visitor, isExpression));