From 49568445dc126bf84ebcb8d73eb7fcddcb12f4f5 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Wed, 6 Dec 2017 14:11:12 -0800
Subject: [PATCH] In createNodeArray, create a fresh array

---
 src/compiler/factory.ts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index dfc22e3183374..2722a3394fd0f 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -28,6 +28,8 @@ namespace ts {
             if (isNodeArray(elements)) {
                 return elements;
             }
+            // elements is a ReadonlyArray, so create a fresh array before adding properties.
+            elements = elements.slice();
         }
         else {
             elements = [];