From 3a1fb1bea6c489771630af95e56882bc4a2386ae Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 11 Jun 2019 09:25:00 -0700
Subject: [PATCH] Properly preserve CheckFlags.Readonly when widening
 properties

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index ff2360d57a0..2e7c89f235a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -14630,7 +14630,7 @@ namespace ts {
         }
 
         function createSymbolWithType(source: Symbol, type: Type | undefined) {
-            const symbol = createSymbol(source.flags, source.escapedName);
+            const symbol = createSymbol(source.flags, source.escapedName, getCheckFlags(source) & CheckFlags.Readonly);
             symbol.declarations = source.declarations;
             symbol.parent = source.parent;
             symbol.type = type;