[esnext] Fix various callsites to use is_resumable, not is_generator

Async functions are built out of generators, but the
SharedFunctionInfo returns false for is_generator. is_resumable is
the broader query. This patch fixes many parts of V8 to refer
to is_resumable as appropriate.

One incidental change is to remove a check for generators extending
classes. This is part of a general check for constructors being the
only thing which can extend classes, so it is removed here and the
error message for the general case is made more accurate.

BUG=v8:4483

Review-Url: https://codereview.chromium.org/1996943002
Cr-Commit-Position: refs/heads/master@{#36621}

src/compiler.cc

@@ -874,10 +874,11 @@ MaybeHandle<Code> GetBaselineCode(Handle<JSFunction> function) {
     return MaybeHandle<Code>();
   }
 
-  // TODO(4280): For now we do not switch generators to baseline code because
-  // there might be suspended activations stored in generator objects on the
-  // heap. We could eventually go directly to TurboFan in this case.
-  if (function->shared()->is_generator()) {
+  // TODO(4280): For now we do not switch generators or async functions to
+  // baseline code because there might be suspended activations stored in
+  // generator objects on the heap. We could eventually go directly to
+  // TurboFan in this case.
+  if (function->shared()->is_resumable()) {
     return MaybeHandle<Code>();
   }
 
@@ -1308,10 +1309,11 @@ bool Compiler::EnsureDeoptimizationSupport(CompilationInfo* info) {
     CompilationInfo unoptimized(info->parse_info(), info->closure());
     unoptimized.EnableDeoptimizationSupport();
 
-    // TODO(4280): For now we do not switch generators to baseline code because
-    // there might be suspended activations stored in generator objects on the
-    // heap. We could eventually go directly to TurboFan in this case.
-    if (shared->is_generator()) return false;
+    // TODO(4280): For now we do not switch generators or async functions to
+    // baseline code because there might be suspended activations stored in
+    // generator objects on the heap. We could eventually go directly to
+    // TurboFan in this case.
+    if (shared->is_resumable()) return false;
 
     // TODO(4280): For now we disable switching to baseline code in the presence
     // of interpreter activations of the given function. The reasons are:

src/debug/debug.cc

@@ -1325,7 +1325,7 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
     // smarter here and avoid the heap walk.
     HeapIterator iterator(isolate_->heap());
     HeapObject* obj;
-    bool include_generators = !is_interpreted && shared->is_generator();
+    bool find_resumables = !is_interpreted && shared->is_resumable();
 
     while ((obj = iterator.next())) {
       if (obj->IsJSFunction()) {
@@ -1336,7 +1336,9 @@ bool Debug::PrepareFunctionForBreakPoints(Handle<SharedFunctionInfo> shared) {
         }
         if (is_interpreted) continue;
         if (function->shared() == *shared) functions.Add(handle(function));
-      } else if (include_generators && obj->IsJSGeneratorObject()) {
+      } else if (find_resumables && obj->IsJSGeneratorObject()) {
+        // This case handles async functions as well, as they use generator
+        // objects for in-progress async function execution.
         JSGeneratorObject* generator_obj = JSGeneratorObject::cast(obj);
         if (!generator_obj->is_suspended()) continue;
         JSFunction* function = generator_obj->function();

src/debug/liveedit.cc

@@ -1680,7 +1680,7 @@ static const char* DropActivationsInActiveThreadImpl(Isolate* isolate,
     if (frame->is_java_script()) {
       SharedFunctionInfo* shared =
           JavaScriptFrame::cast(frame)->function()->shared();
-      if (shared->is_generator()) {
+      if (shared->is_resumable()) {
         non_droppable_frame_found = true;
         non_droppable_reason = LiveEdit::FUNCTION_BLOCKED_UNDER_GENERATOR;
         break;

src/factory.cc

@@ -1298,7 +1298,10 @@ Handle<JSFunction> Factory::NewFunction(Handle<String> name, Handle<Code> code,
   ElementsKind elements_kind =
       type == JS_ARRAY_TYPE ? FAST_SMI_ELEMENTS : FAST_HOLEY_SMI_ELEMENTS;
   Handle<Map> initial_map = NewMap(type, instance_size, elements_kind);
-  if (!function->shared()->is_generator()) {
+  // TODO(littledan): Why do we have this is_generator test when
+  // NewFunctionPrototype already handles finding an appropriately
+  // shared prototype?
+  if (!function->shared()->is_resumable()) {
     if (prototype->IsTheHole()) {
       prototype = NewFunctionPrototype(function);
     } else if (install_constructor) {
@@ -1327,11 +1330,12 @@ Handle<JSObject> Factory::NewFunctionPrototype(Handle<JSFunction> function) {
   // can be from a different context.
   Handle<Context> native_context(function->context()->native_context());
   Handle<Map> new_map;
-  if (function->shared()->is_generator()) {
-    // Generator prototypes can share maps since they don't have "constructor"
-    // properties.
+  if (function->shared()->is_resumable()) {
+    // Generator and async function prototypes can share maps since they
+    // don't have "constructor" properties.
     new_map = handle(native_context->generator_object_prototype_map());
   } else {
+    CHECK(!function->shared()->is_async());
     // Each function prototype gets a fresh map to avoid unwanted sharing of
     // maps between prototypes of different constructors.
     Handle<JSFunction> object_function(native_context->object_function());
@@ -1342,7 +1346,7 @@ Handle<JSObject> Factory::NewFunctionPrototype(Handle<JSFunction> function) {
   DCHECK(!new_map->is_prototype_map());
   Handle<JSObject> prototype = NewJSObjectFromMap(new_map);
 
-  if (!function->shared()->is_generator()) {
+  if (!function->shared()->is_resumable()) {
     JSObject::AddProperty(prototype, constructor_string(), function, DONT_ENUM);
   }
 

src/messages.h

@@ -121,10 +121,8 @@ class CallSite {
   T(DefineDisallowed, "Cannot define property:%, object is not extensible.")   \
   T(DetachedOperation, "Cannot perform % on a detached ArrayBuffer")           \
   T(DuplicateTemplateProperty, "Object template has duplicate property '%'")   \
-  T(ExtendsValueGenerator,                                                     \
-    "Class extends value % may not be a generator function")                   \
-  T(ExtendsValueNotFunction,                                                   \
-    "Class extends value % is not a function or null")                         \
+  T(ExtendsValueNotConstructor,                                                \
+    "Class extends value % is not a constructor or null")                      \
   T(FirstArgumentNotRegExp,                                                    \
     "First argument to % must not be a regular expression")                    \
   T(FunctionBind, "Bind must be called on a function")                         \

src/objects-printer.cc

@@ -876,6 +876,8 @@ void JSFunction::JSFunctionPrint(std::ostream& os) {  // NOLINT
      << shared()->internal_formal_parameter_count();
   if (shared()->is_generator()) {
     os << "\n   - generator";
+  } else if (shared()->is_async()) {
+    os << "\n   - async";
   }
   os << "\n - context = " << Brief(context());
   os << "\n - literals = " << Brief(literals());

src/runtime/runtime-classes.cc

@@ -94,13 +94,8 @@ static MaybeHandle<Object> DefineClass(Isolate* isolate,
     if (super_class->IsNull()) {
       prototype_parent = isolate->factory()->null_value();
     } else if (super_class->IsConstructor()) {
-      if (super_class->IsJSFunction() &&
-          Handle<JSFunction>::cast(super_class)->shared()->is_generator()) {
-        THROW_NEW_ERROR(
-            isolate,
-            NewTypeError(MessageTemplate::kExtendsValueGenerator, super_class),
-            Object);
-      }
+      DCHECK(!super_class->IsJSFunction() ||
+             !Handle<JSFunction>::cast(super_class)->shared()->is_resumable());
       ASSIGN_RETURN_ON_EXCEPTION(
           isolate, prototype_parent,
           Runtime::GetObjectProperty(isolate, super_class,
@@ -114,10 +109,10 @@ static MaybeHandle<Object> DefineClass(Isolate* isolate,
       }
       constructor_parent = super_class;
     } else {
-      THROW_NEW_ERROR(
-          isolate,
-          NewTypeError(MessageTemplate::kExtendsValueNotFunction, super_class),
-          Object);
+      THROW_NEW_ERROR(isolate,
+                      NewTypeError(MessageTemplate::kExtendsValueNotConstructor,
+                                   super_class),
+                      Object);
     }
   }
 

test/cctest/interpreter/bytecode_expectations/ForOf.golden

@@ -91,7 +91,7 @@ bytecodes: [
                 B(TestEqualStrict), R(12),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(128),
                 B(Star), R(12),
                 B(LdaConstant), U8(8),
                 B(Star), R(13),
@@ -236,7 +236,7 @@ bytecodes: [
                 B(TestEqualStrict), R(13),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(128),
                 B(Star), R(13),
                 B(LdaConstant), U8(8),
                 B(Star), R(14),
@@ -393,7 +393,7 @@ bytecodes: [
                 B(TestEqualStrict), R(12),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(128),
                 B(Star), R(12),
                 B(LdaConstant), U8(8),
                 B(Star), R(13),
@@ -540,7 +540,7 @@ bytecodes: [
                 B(TestEqualStrict), R(11),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(128),
                 B(Star), R(11),
                 B(LdaConstant), U8(10),
                 B(Star), R(12),

test/cctest/interpreter/bytecode_expectations/Generators.golden

@@ -480,7 +480,7 @@ bytecodes: [
                 B(TestEqualStrict), R(10),
                 B(JumpIfFalse), U8(4),
                 B(Jump), U8(18),
-                B(Wide), B(LdaSmi), U16(129),
+                B(Wide), B(LdaSmi), U16(128),
                 B(Star), R(10),
                 B(LdaConstant), U8(14),
                 B(Star), R(11),

test/mjsunit/debug-generator-break-on-stack.js

+// Copyright 2016 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: --expose-debug-as debug
+
+var Debug = debug.Debug;
+
+var break_count = 0;
+var exception = null;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    break_count++;
+    var line = exec_state.frame(0).sourceLineText();
+    print(line);
+    assertTrue(line.indexOf(`B${break_count}`) > 0);
+  } catch (e) {
+    exception = e;
+  }
+}
+
+
+function* g() {
+  setbreaks();
+  yield 1;  // B1
+}
+
+function* f() {
+  yield* g();
+  return 2;  // B2
+}
+
+function setbreaks() {
+  Debug.setListener(listener);
+  Debug.setBreakPoint(g, 2);
+  Debug.setBreakPoint(f, 2);
+}
+
+for (let _ of f()) { }
+
+assertEquals(2, break_count);
+assertNull(exception);
+
+Debug.setListener(null);

test/mjsunit/debug-generator-break.js

+// Copyright 2016 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: --expose-debug-as debug
+
+var Debug = debug.Debug;
+
+var break_count = 0;
+var exception = null;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    break_count++;
+    var line = exec_state.frame(0).sourceLineText();
+    assertTrue(line.indexOf(`B${break_count}`) > 0);
+  } catch (e) {
+    exception = e;
+  }
+}
+
+Debug.setListener(listener);
+
+function* g() {
+  yield 1;
+}
+
+function* f() {
+  yield* g();                    // B1
+  assertEquals(2, break_count);  // B2
+  return 1;                      // B3
+}
+
+Debug.setBreakPoint(f, 1);
+Debug.setBreakPoint(f, 2);
+Debug.setBreakPoint(f, 3);
+
+for (let _ of f()) { }
+
+assertEquals(3, break_count);
+assertNull(exception);
+
+Debug.setListener(null);

test/mjsunit/harmony/async-await-basic.js

@@ -345,3 +345,6 @@ assertEquals("async x => { return x }", (async x => { return x }).toString());
 class AsyncMethod { async foo() { } }
 assertEquals("async foo() { }", Function.prototype.toString.call(AsyncMethod.prototype.foo));
 assertEquals("async foo() { }", Function.prototype.toString.call({async foo() { }}.foo));
+
+// Async functions are not constructible
+assertThrows(() => class extends (async function() {}) {}, TypeError);

test/mjsunit/harmony/debug-async-break-on-stack.js

+// Copyright 2016 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: --expose-debug-as debug
+// Flags: --harmony-async-await --allow-natives-syntax
+
+var Debug = debug.Debug;
+
+function assertEqualsAsync(expected, run, msg) {
+  var actual;
+  var hadValue = false;
+  var hadError = false;
+  var promise = run();
+
+  if (typeof promise !== "object" || typeof promise.then !== "function") {
+    throw new MjsUnitAssertionError(
+        "Expected " + run.toString() +
+        " to return a Promise, but it returned " + promise);
+  }
+
+  promise.then(function(value) { hadValue = true; actual = value; },
+               function(error) { hadError = true; actual = error; });
+
+  assertFalse(hadValue || hadError);
+
+  %RunMicrotasks();
+
+  if (hadError) throw actual;
+
+  assertTrue(
+      hadValue, "Expected '" + run.toString() + "' to produce a value");
+
+  assertEquals(expected, actual, msg);
+}
+
+var break_count = 0;
+var exception = null;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    break_count++;
+    var line = exec_state.frame(0).sourceLineText();
+    print(line);
+    assertTrue(line.indexOf(`B${break_count}`) > 0);
+  } catch (e) {
+    exception = e;
+  }
+}
+
+
+async function g() {
+  setbreaks();
+  throw 1;  // B1
+}
+
+async function f() {
+  try {
+    await g();
+  } catch (e) {}
+  return 2;  // B2
+}
+
+function setbreaks() {
+  Debug.setListener(listener);
+  Debug.setBreakPoint(g, 2);
+  Debug.setBreakPoint(f, 4);
+}
+
+f();
+
+%RunMicrotasks();
+
+assertEqualsAsync(2, async () => break_count);
+assertEqualsAsync(null, async () => exception);
+
+Debug.setListener(null);

test/mjsunit/harmony/debug-async-break.js

+// Copyright 2016 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: --expose-debug-as debug
+// Flags: --harmony-async-await --allow-natives-syntax
+
+var Debug = debug.Debug;
+
+function assertEqualsAsync(expected, run, msg) {
+  var actual;
+  var hadValue = false;
+  var hadError = false;
+  var promise = run();
+
+  if (typeof promise !== "object" || typeof promise.then !== "function") {
+    throw new MjsUnitAssertionError(
+        "Expected " + run.toString() +
+        " to return a Promise, but it returned " + promise);
+  }
+
+  promise.then(function(value) { hadValue = true; actual = value; },
+               function(error) { hadError = true; actual = error; });
+
+  assertFalse(hadValue || hadError);
+
+  %RunMicrotasks();
+
+  if (hadError) throw actual;
+
+  assertTrue(
+      hadValue, "Expected '" + run.toString() + "' to produce a value");
+
+  assertEquals(expected, actual, msg);
+}
+
+var break_count = 0;
+var exception = null;
+
+function listener(event, exec_state, event_data, data) {
+  if (event != Debug.DebugEvent.Break) return;
+  try {
+    break_count++;
+    var line = exec_state.frame(0).sourceLineText();
+    assertTrue(line.indexOf(`B${break_count}`) > 0);
+  } catch (e) {
+    exception = e;
+  }
+}
+
+Debug.setListener(listener);
+
+async function g() {
+  throw 1;
+}
+
+async function f() {
+  try {
+    await g();                   // B1
+  } catch (e) {}
+  assertEquals(2, break_count);  // B2
+  return 1;                      // B3
+}
+
+Debug.setBreakPoint(f, 2);
+Debug.setBreakPoint(f, 4);
+Debug.setBreakPoint(f, 5);
+
+f();
+
+%RunMicrotasks();
+
+assertEqualsAsync(3, async () => break_count);
+assertEqualsAsync(null, async () => exception);
+
+Debug.setListener(null);

test/webkit/class-syntax-extends-expected.txt

@@ -23,8 +23,8 @@ PASS x.prototype.__proto__ is Base.prototype
 PASS Object.getPrototypeOf(x.prototype) is Base.prototype
 PASS x = class extends null { constructor() { } }; x.__proto__ is Function.prototype
 PASS x.__proto__ is Function.prototype
-PASS x = class extends 3 { constructor() { } }; x.__proto__ threw exception TypeError: Class extends value 3 is not a function or null.
-PASS x = class extends "abc" { constructor() { } }; x.__proto__ threw exception TypeError: Class extends value abc is not a function or null.
+PASS x = class extends 3 { constructor() { } }; x.__proto__ threw exception TypeError: Class extends value 3 is not a constructor or null.
+PASS x = class extends "abc" { constructor() { } }; x.__proto__ threw exception TypeError: Class extends value abc is not a constructor or null.
 PASS baseWithBadPrototype = function () {}; baseWithBadPrototype.prototype = 3; new baseWithBadPrototype did not throw exception.
 PASS x = class extends baseWithBadPrototype { constructor() { } } threw exception TypeError: Class extends value does not have valid prototype property 3.
 PASS baseWithBadPrototype.prototype = "abc" did not throw exception.
@@ -32,8 +32,8 @@ PASS x = class extends baseWithBadPrototype { constructor() { } } threw exceptio
 PASS baseWithBadPrototype.prototype = null; x = class extends baseWithBadPrototype { constructor() { } } did not throw exception.
 PASS x = 1; c = class extends ++x { constructor() { } }; threw exception SyntaxError: Unexpected token ++.
 PASS x = 1; c = class extends x++ { constructor() { } }; threw exception SyntaxError: Unexpected token ++.
-PASS x = 1; c = class extends (++x) { constructor() { } }; threw exception TypeError: Class extends value 2 is not a function or null.
-PASS x = 1; c = class extends (x++) { constructor() { } }; threw exception TypeError: Class extends value 1 is not a function or null.
+PASS x = 1; c = class extends (++x) { constructor() { } }; threw exception TypeError: Class extends value 2 is not a constructor or null.
+PASS x = 1; c = class extends (x++) { constructor() { } }; threw exception TypeError: Class extends value 1 is not a constructor or null.
 PASS x = 1; try { c = class extends (++x) { constructor() { } } } catch (e) { }; x is 2
 PASS x = 1; try { c = class extends (x++) { constructor() { } } } catch (e) { }; x is 2
 PASS namespace = {}; namespace.A = class { }; namespace.B = class extends namespace.A { } did not throw exception.
@@ -47,17 +47,17 @@ PASS namespace = {}; namespace.A = class { constructor() { } }; function getClas
 PASS namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends (false||null||namespace.A) { constructor() { } } did not throw exception.
 PASS namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends false||null||namespace.A { constructor() { } } threw exception SyntaxError: Unexpected token ||.
 PASS x = 1; namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends (x++, namespace.A) { constructor() { } }; did not throw exception.
-PASS x = 1; namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends (namespace.A, x++) { constructor() { } }; threw exception TypeError: Class extends value 1 is not a function or null.
-PASS namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends new namespace.A { constructor() { } } threw exception TypeError: Class extends value [object Object] is not a function or null.
-PASS namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends new namespace.A() { constructor() { } } threw exception TypeError: Class extends value [object Object] is not a function or null.
+PASS x = 1; namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends (namespace.A, x++) { constructor() { } }; threw exception TypeError: Class extends value 1 is not a constructor or null.
+PASS namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends new namespace.A { constructor() { } } threw exception TypeError: Class extends value [object Object] is not a constructor or null.
+PASS namespace = {}; namespace.A = class { constructor() { } }; namespace.B = class extends new namespace.A() { constructor() { } } threw exception TypeError: Class extends value [object Object] is not a constructor or null.
 PASS x = 1; namespace = {}; namespace.A = class { constructor() { } }; try { namespace.B = class extends (x++, namespace.A) { constructor() { } } } catch (e) { } x is 2
 PASS x = 1; namespace = {}; namespace.A = class { constructor() { } }; try { namespace.B = class extends (namespace.A, x++) { constructor() { } } } catch (e) { } x is 2
 PASS Object.getPrototypeOf((class { constructor () { } }).prototype) is Object.prototype
 PASS Object.getPrototypeOf((class extends null { constructor () { super(); } }).prototype) is null
-PASS new (class extends undefined { constructor () { this } }) threw exception TypeError: Class extends value undefined is not a function or null.
-PASS new (class extends undefined { constructor () { super(); } }) threw exception TypeError: Class extends value undefined is not a function or null.
-PASS x = {}; new (class extends undefined { constructor () { return x; } }) threw exception TypeError: Class extends value undefined is not a function or null.
-PASS y = 12; new (class extends undefined { constructor () { return y; } }) threw exception TypeError: Class extends value undefined is not a function or null.
+PASS new (class extends undefined { constructor () { this } }) threw exception TypeError: Class extends value undefined is not a constructor or null.
+PASS new (class extends undefined { constructor () { super(); } }) threw exception TypeError: Class extends value undefined is not a constructor or null.
+PASS x = {}; new (class extends undefined { constructor () { return x; } }) threw exception TypeError: Class extends value undefined is not a constructor or null.
+PASS y = 12; new (class extends undefined { constructor () { return y; } }) threw exception TypeError: Class extends value undefined is not a constructor or null.
 PASS class x {}; new (class extends null { constructor () { return new x; } }) instanceof x is true
 PASS new (class extends null { constructor () { this; } }) threw exception ReferenceError: this is not defined.
 PASS new (class extends null { constructor () { super(); } }) threw exception TypeError: super is not a constructor.

test/webkit/class-syntax-extends.js

@@ -58,8 +58,8 @@ shouldBe('x.prototype.__proto__', 'Base.prototype');
 shouldBe('Object.getPrototypeOf(x.prototype)', 'Base.prototype');
 shouldBe('x = class extends null { constructor() { } }; x.__proto__', 'Function.prototype');
 shouldBe('x.__proto__', 'Function.prototype');
-shouldThrow('x = class extends 3 { constructor() { } }; x.__proto__', '"TypeError: Class extends value 3 is not a function or null"');
-shouldThrow('x = class extends "abc" { constructor() { } }; x.__proto__', '"TypeError: Class extends value abc is not a function or null"');
+shouldThrow('x = class extends 3 { constructor() { } }; x.__proto__', '"TypeError: Class extends value 3 is not a constructor or null"');
+shouldThrow('x = class extends "abc" { constructor() { } }; x.__proto__', '"TypeError: Class extends value abc is not a constructor or null"');
 shouldNotThrow('baseWithBadPrototype = function () {}; baseWithBadPrototype.prototype = 3; new baseWithBadPrototype');
 shouldThrow('x = class extends baseWithBadPrototype { constructor() { } }', '"TypeError: Class extends value does not have valid prototype property 3"');
 shouldNotThrow('baseWithBadPrototype.prototype = "abc"');
@@ -92,10 +92,10 @@ shouldBe('x = 1; namespace = {}; namespace.A = class { constructor() { } }; try
 
 shouldBe('Object.getPrototypeOf((class { constructor () { } }).prototype)', 'Object.prototype');
 shouldBe('Object.getPrototypeOf((class extends null { constructor () { super(); } }).prototype)', 'null');
-shouldThrow('new (class extends undefined { constructor () { this } })', '"TypeError: Class extends value undefined is not a function or null"');
-shouldThrow('new (class extends undefined { constructor () { super(); } })', '"TypeError: Class extends value undefined is not a function or null"');
-shouldThrow('x = {}; new (class extends undefined { constructor () { return x; } })', '"TypeError: Class extends value undefined is not a function or null"');
-shouldThrow('y = 12; new (class extends undefined { constructor () { return y; } })', '"TypeError: Class extends value undefined is not a function or null"');
+shouldThrow('new (class extends undefined { constructor () { this } })', '"TypeError: Class extends value undefined is not a constructor or null"');
+shouldThrow('new (class extends undefined { constructor () { super(); } })', '"TypeError: Class extends value undefined is not a constructor or null"');
+shouldThrow('x = {}; new (class extends undefined { constructor () { return x; } })', '"TypeError: Class extends value undefined is not a constructor or null"');
+shouldThrow('y = 12; new (class extends undefined { constructor () { return y; } })', '"TypeError: Class extends value undefined is not a constructor or null"');
 shouldBeTrue ('class x {}; new (class extends null { constructor () { return new x; } }) instanceof x');
 shouldThrow('new (class extends null { constructor () { this; } })', '"ReferenceError: this is not defined"');
 shouldThrow('new (class extends null { constructor () { super(); } })', '"TypeError: super is not a constructor"');