Merge pull request #12434 from Microsoft/Fix12377

Add special handeling for function and array in Object.freeze

Author: mhegazy

src/lib/es5.d.ts

@@ -176,6 +176,18 @@ interface ObjectConstructor {
       */
     seal<T>(o: T): T;
 
+    /**
+      * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
+      * @param o Object on which to lock the attributes.
+      */
+    freeze<T>(a: T[]): ReadonlyArray<T>;
+
+    /**
+      * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
+      * @param o Object on which to lock the attributes.
+      */
+    freeze<T extends Function>(f: T): T;
+
     /**
       * Prevents the modification of existing property attributes and values, and prevents the addition of new properties.
       * @param o Object on which to lock the attributes.

tests/baselines/reference/objectFreeze.errors.txt

@@ -0,0 +1,22 @@
+tests/cases/compiler/objectFreeze.ts(9,1): error TS2542: Index signature in type 'ReadonlyArray<number>' only permits reading.
+tests/cases/compiler/objectFreeze.ts(12,3): error TS2540: Cannot assign to 'b' because it is a constant or a read-only property.
+
+
+==== tests/cases/compiler/objectFreeze.ts (2 errors) ====
+    const f = Object.freeze(function foo(a: number, b: string) { return false; });
+    f(1, "") === false;
+    
+    class C { constructor(a: number) { } }
+    const c = Object.freeze(C);
+    new c(1);
+    
+    const a = Object.freeze([1, 2, 3]);
+    a[0] = a[2].toString();
+    ~~~~
+!!! error TS2542: Index signature in type 'ReadonlyArray<number>' only permits reading.
+    
+    const o = Object.freeze({ a: 1, b: "string" });
+    o.b = o.a.toString();
+      ~
+!!! error TS2540: Cannot assign to 'b' because it is a constant or a read-only property.
+    

tests/baselines/reference/objectFreeze.js

@@ -0,0 +1,29 @@
+//// [objectFreeze.ts]
+const f = Object.freeze(function foo(a: number, b: string) { return false; });
+f(1, "") === false;
+
+class C { constructor(a: number) { } }
+const c = Object.freeze(C);
+new c(1);
+
+const a = Object.freeze([1, 2, 3]);
+a[0] = a[2].toString();
+
+const o = Object.freeze({ a: 1, b: "string" });
+o.b = o.a.toString();
+
+
+//// [objectFreeze.js]
+var f = Object.freeze(function foo(a, b) { return false; });
+f(1, "") === false;
+var C = (function () {
+    function C(a) {
+    }
+    return C;
+}());
+var c = Object.freeze(C);
+new c(1);
+var a = Object.freeze([1, 2, 3]);
+a[0] = a[2].toString();
+var o = Object.freeze({ a: 1, b: "string" });
+o.b = o.a.toString();

tests/cases/compiler/objectFreeze.ts

@@ -0,0 +1,12 @@
+const f = Object.freeze(function foo(a: number, b: string) { return false; });
+f(1, "") === false;
+
+class C { constructor(a: number) { } }
+const c = Object.freeze(C);
+new c(1);
+
+const a = Object.freeze([1, 2, 3]);
+a[0] = a[2].toString();
+
+const o = Object.freeze({ a: 1, b: "string" });
+o.b = o.a.toString();