[strong] class objects created in strong mode are frozen

test/mjsunit/strong/class-object-frozen.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --strong-mode
+
+"use strict";
+
+function getClass() {
+  class Foo {
+    static get bar() { return 0 }
+  }
+  return Foo;
+}
+
+function getClassExpr() {
+  return (class { static get bar() { return 0 } });
+}
+
+function getClassStrong() {
+  "use strong";
+  class Foo {
+    static get bar() { return 0 }
+  }
+  return Foo;
+}
+
+function getClassExprStrong() {
+  "use strong";
+  return (class { static get bar() { return 0 } });
+}
+
+function addProperty(o) {
+  o.baz = 1;
+}
+
+function convertPropertyToData(o) {
+  assertTrue(o.hasOwnProperty("bar"));
+  Object.defineProperty(o, "bar", { value: 1 });
+}
+
+assertDoesNotThrow(function(){addProperty(getClass())});
+assertDoesNotThrow(function(){convertPropertyToData(getClass())});
+assertDoesNotThrow(function(){addProperty(getClassExpr())});
+assertDoesNotThrow(function(){convertPropertyToData(getClassExpr())});
+
+assertThrows(function(){addProperty(getClassStrong())}, TypeError);
+assertThrows(function(){convertPropertyToData(getClassStrong())}, TypeError);
+assertThrows(function(){addProperty(getClassExprStrong())}, TypeError);
+assertThrows(function(){convertPropertyToData(getClassExprStrong())},
+             TypeError);
+
+// Check strong classes don't freeze their parents.
+(function() {
+  "use strong";
+  let parent = getClass();
+
+  class Foo extends parent {
+    static get bar() { return 0 }
+  }
+
+  assertThrows(function(){addProperty(Foo)}, TypeError);
+  assertThrows(function(){convertPropertyToData(Foo)}, TypeError);
+  assertDoesNotThrow(function(){addProperty(parent)});
+  assertDoesNotThrow(function(){convertPropertyToData(parent)});
+})();
+
+// Check strong classes don't freeze their children.
+(function() {
+  let parent = getClassStrong();
+
+  class Foo extends parent {
+    static get bar() { return 0 }
+  }
+
+  assertThrows(function(){addProperty(parent)}, TypeError);
+  assertThrows(function(){convertPropertyToData(parent)}, TypeError);
+  assertDoesNotThrow(function(){addProperty(Foo)});
+  assertDoesNotThrow(function(){convertPropertyToData(Foo)});
+})();