Implement handling of arrow functions in the parser

src/preparser.cc

Index: src/preparser.cc
diff --git a/src/preparser.cc b/src/preparser.cc
index 459cb6ae8a3bd00491ff90b75a88d8b12869650b..29b5c2fe41c5ca4071a85a4ef9a28e38f0527205 100644
--- a/src/preparser.cc
+++ b/src/preparser.cc
@@ -136,13 +136,14 @@ PreParserExpression PreParserTraits::ParseFunctionLiteral(
     PreParserIdentifier name,
     Scanner::Location function_name_location,
     bool name_is_strict_reserved,
-    bool is_generator,
+    FunctionParsingMode parsing_mode,
+    PreParserExpression params_ast,
     int function_token_position,
     FunctionLiteral::FunctionType type,
     bool* ok) {
   return pre_parser_->ParseFunctionLiteral(
-      name, function_name_location, name_is_strict_reserved, is_generator,
-      function_token_position, type, ok);
+      name, function_name_location, name_is_strict_reserved, parsing_mode,
+      params_ast, function_token_position, type, ok);
 }
 
 
@@ -355,14 +356,17 @@ PreParser::Statement PreParser::ParseFunctionDeclaration(bool* ok) {
   //      '{' FunctionBody '}'
   Expect(Token::FUNCTION, CHECK_OK);
   int pos = position();
-  bool is_generator = allow_generators() && Check(Token::MUL);
+  FunctionParsingMode parsing_mode = (allow_generators() && Check(Token::MUL))
+      ? kGeneratorFunction
+      : kNormalFunction;
   bool is_strict_reserved = false;
   Identifier name = ParseIdentifierOrStrictReservedWord(
       &is_strict_reserved, CHECK_OK);
   ParseFunctionLiteral(name,
                        scanner()->location(),
                        is_strict_reserved,
-                       is_generator,
+                       parsing_mode,
+                       EmptyExpression(),
                        pos,
                        FunctionLiteral::DECLARATION,
                        CHECK_OK);
@@ -841,7 +845,8 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
     Identifier function_name,
     Scanner::Location function_name_location,
     bool name_is_strict_reserved,
-    bool is_generator,
+    FunctionParsingMode parsing_mode,
+    PreParserExpression params_ast,
     int function_token_pos,
     FunctionLiteral::FunctionType function_type,
     bool* ok) {
@@ -853,7 +858,7 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
   bool inside_with = scope_->inside_with();
   PreParserScope function_scope(scope_, FUNCTION_SCOPE);
   FunctionState function_state(&function_state_, &scope_, &function_scope);
-  function_state.set_is_generator(is_generator);
+  function_state.set_is_generator(parsing_mode == kGeneratorFunction);
   //  FormalParameterList ::
   //    '(' (Identifier)*[','] ')'
   Expect(Token::LPAREN, CHECK_OK);