Merge pull request #31858 from microsoft/fixReadonlyPropertyWidening

Fix readonly property widening

Author: ahejlsberg

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;

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;
         };
     };

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