new classes: special construct stub for derived classs and TDZ for `this`.

src/preparser.cc

 // Copyright 2011 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.
 
 #include <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 986 matching lines @@
     ReportMessageAt(class_name_location, "strict_eval_arguments");
     *ok = false;
     return EmptyExpression();
   }
 
   PreParserScope scope = NewScope(scope_, BLOCK_SCOPE);
   BlockState block_state(&scope_, &scope);
   scope_->SetStrictMode(STRICT);
   scope_->SetScopeName(name);
 
-  if (Check(Token::EXTENDS)) {
-    ParseLeftHandSideExpression(CHECK_OK);
-  }
+  bool has_extends = Check(Token::EXTENDS);
+  if (has_extends) ParseLeftHandSideExpression(CHECK_OK);

[rossberg, 2015/02/03 15:52:42]

Actually, I just realised that you need to put braces around this, or the
CHECK_OK macro will screw you over. 8-}

[Dmitry Lomov (no reviews), 2015/02/03 15:59:13]

Good catch, done.

 
   ClassLiteralChecker checker(this);
   bool has_seen_constructor = false;
 
   Expect(Token::LBRACE, CHECK_OK);
   while (peek() != Token::RBRACE) {
     if (Check(Token::SEMICOLON)) continue;
     const bool in_class = true;
     const bool is_static = false;
     bool is_computed_name = false;  // Classes do not care about computed
                                     // property names here.
-    ParsePropertyDefinition(&checker, in_class, is_static, &is_computed_name,
-                            &has_seen_constructor, CHECK_OK);
+    ParsePropertyDefinition(&checker, in_class, has_extends, is_static,
+                            &is_computed_name, &has_seen_constructor, CHECK_OK);
   }
 
   Expect(Token::RBRACE, CHECK_OK);
 
   return Expression::Default();
 }
 
 
 PreParser::Expression PreParser::ParseV8Intrinsic(bool* ok) {
   // CallRuntime ::
   //   '%' Identifier Arguments
   Expect(Token::MOD, CHECK_OK);
   if (!allow_natives()) {
     *ok = false;
     return Expression::Default();
   }
   // Allow "eval" or "arguments" for backward compatibility.
   ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
   ParseArguments(ok);
 
   return Expression::Default();
 }
 
 #undef CHECK_OK
 
 
 } }  // v8::internal