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 1/2] 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;

From 0ca078b345a7e95dff602292df2f55a99cb64b85 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 11 Jun 2019 09:25:23 -0700
Subject: [PATCH 2/2] Accept new baselines

---
 tests/baselines/reference/constAssertions.js    | 4 ++--
 tests/baselines/reference/constAssertions.types | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/baselines/reference/constAssertions.js b/tests/baselines/reference/constAssertions.js
index 9f173987d22..21369cb3423 100644
--- a/tests/baselines/reference/constAssertions.js
+++ b/tests/baselines/reference/constAssertions.js
@@ -200,8 +200,8 @@ declare let p4: readonly [readonly [readonly [readonly [10]]]];
 declare let x1: {
     readonly x: 10;
     readonly y: readonly [20, 30];
-    z: {
-        a: {
+    readonly z: {
+        readonly a: {
             readonly b: 42;
         };
     };
diff --git a/tests/baselines/reference/constAssertions.types b/tests/baselines/reference/constAssertions.types
index b1f90df15f0..b02988aea1b 100644
--- a/tests/baselines/reference/constAssertions.types
+++ b/tests/baselines/reference/constAssertions.types
@@ -281,7 +281,7 @@ let p4 = [[[[10]]]] as const;
 >10 : 10
 
 let x1 = { x: 10, y: [20, 30], z: { a: { b: 42 } } } as const;
->x1 : { readonly x: 10; readonly y: readonly [20, 30]; z: { a: { readonly b: 42; }; }; }
+>x1 : { readonly x: 10; readonly y: readonly [20, 30]; readonly z: { readonly a: { readonly b: 42; }; }; }
 >{ x: 10, y: [20, 30], z: { a: { b: 42 } } } as const : { readonly x: 10; readonly y: readonly [20, 30]; readonly z: { readonly a: { readonly b: 42; }; }; }
 >{ x: 10, y: [20, 30], z: { a: { b: 42 } } } : { readonly x: 10; readonly y: readonly [20, 30]; readonly z: { readonly a: { readonly b: 42; }; }; }
 >x : 10