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

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index ec9832111aa9306ccf124ebc62237cd091fbcf1a..d7bd891df8b231b9c9e72d7aab047f31f6ac7604 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -263,11 +263,16 @@ void Parser::SetCachedData() {
 }
 
 
-Scope* Parser::NewScope(Scope* parent, ScopeType scope_type) {
+Scope* Parser::NewScope(Scope* parent, ScopeType scope_type,
+                        FunctionKind kind) {
   DCHECK(ast_value_factory());
+  DCHECK((scope_type == FUNCTION_SCOPE && IsValidFunctionKind(kind)) ||
+         kind == kNormalFunction);
   Scope* result =
       new (zone()) Scope(parent, scope_type, ast_value_factory(), zone());
-  result->Initialize();
+  bool uninitialized_this =
+      FLAG_experimental_classes && IsSubclassConstructor(kind);
+  result->Initialize(uninitialized_this);
   return result;
 }
 
@@ -280,7 +285,8 @@ FunctionLiteral* Parser::DefaultConstructor(bool call_super, Scope* scope,
   int parameter_count = 0;
   const AstRawString* name = ast_value_factory()->empty_string();
 
-  Scope* function_scope = NewScope(scope, FUNCTION_SCOPE);
+  Scope* function_scope =
+      NewScope(scope, FUNCTION_SCOPE, FunctionKind::kDefaultConstructor);
   function_scope->SetStrictMode(STRICT);
   // Set start and end position to the same value
   function_scope->set_start_position(pos);
@@ -3608,11 +3614,11 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
   Scope* original_declaration_scope = original_scope_->DeclarationScope();
   Scope* scope =
       function_type == FunctionLiteral::DECLARATION &&
-      (!allow_harmony_scoping() || strict_mode() == SLOPPY) &&
-      (original_scope_ == original_declaration_scope ||
-       declaration_scope != original_declaration_scope)
-          ? NewScope(declaration_scope, FUNCTION_SCOPE)
-          : NewScope(scope_, FUNCTION_SCOPE);
+              (!allow_harmony_scoping() || strict_mode() == SLOPPY) &&
+              (original_scope_ == original_declaration_scope ||
+               declaration_scope != original_declaration_scope)
+          ? NewScope(declaration_scope, FUNCTION_SCOPE, kind)
+          : NewScope(scope_, FUNCTION_SCOPE, kind);
   ZoneList<Statement*>* body = NULL;
   int materialized_literal_count = -1;
   int expected_property_count = -1;
@@ -4012,6 +4018,7 @@ ClassLiteral* Parser::ParseClassLiteral(const AstRawString* name,
   bool has_seen_constructor = false;
 
   Expect(Token::LBRACE, CHECK_OK);
+  const bool has_extends = extends != nullptr;
   while (peek() != Token::RBRACE) {
     if (Check(Token::SEMICOLON)) continue;
     if (fni_ != NULL) fni_->Enter();
@@ -4019,9 +4026,9 @@ ClassLiteral* Parser::ParseClassLiteral(const AstRawString* name,
     const bool is_static = false;
     bool is_computed_name = false;  // Classes do not care about computed
                                     // property names here.
-    ObjectLiteral::Property* property =
-        ParsePropertyDefinition(NULL, in_class, is_static, &is_computed_name,
-                                &has_seen_constructor, CHECK_OK);
+    ObjectLiteral::Property* property = ParsePropertyDefinition(
+        nullptr, in_class, has_extends, is_static, &is_computed_name,
+        &has_seen_constructor, CHECK_OK);
 
     if (has_seen_constructor && constructor == NULL) {
       constructor = GetPropertyValue(property)->AsFunctionLiteral();