From 44c6cf74cb9761f5471f1129a810c2f96f5f8deb Mon Sep 17 00:00:00 2001
From: Marcel Laverdet <marcel@laverdet.com>
Date: Tue, 5 May 2020 09:05:02 -0700
Subject: [PATCH] Fix `updateBinary` `operator` parameter (#38129)

* Fix `updateBinary` `operator` parameter

There is an issue in `updateBinary` where attempting to update
`operator` without updating `left` or `right` results in a silent no-op.

* Use defaulted parameter in `updateBinary`
---
 src/compiler/factoryPublic.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/compiler/factoryPublic.ts b/src/compiler/factoryPublic.ts
index e17cf3c5054..d78fdfc4dac 100644
--- a/src/compiler/factoryPublic.ts
+++ b/src/compiler/factoryPublic.ts
@@ -1411,10 +1411,11 @@ namespace ts {
         return node;
     }
 
-    export function updateBinary(node: BinaryExpression, left: Expression, right: Expression, operator?: BinaryOperator | BinaryOperatorToken) {
+    export function updateBinary(node: BinaryExpression, left: Expression, right: Expression, operator: BinaryOperator | BinaryOperatorToken = node.operatorToken) {
         return node.left !== left
             || node.right !== right
-            ? updateNode(createBinary(left, operator || node.operatorToken, right), node)
+            || node.operatorToken !== operator
+            ? updateNode(createBinary(left, operator, right), node)
             : node;
     }