Revert "Implement handling of arrow functions in the parser"

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 37e265aa4a059e7530186a301ec9a48ad7b49b1e..3542b4c32409f82fa8079ce729747bc5662d5582 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -718,7 +718,6 @@ Parser::Parser(CompilationInfo* info)
   set_allow_lazy(false);  // Must be explicitly enabled.
   set_allow_generators(FLAG_harmony_generators);
   set_allow_for_of(FLAG_harmony_iteration);
-  set_allow_arrow_functions(FLAG_harmony_arrow_functions);
   set_allow_harmony_numeric_literals(FLAG_harmony_numeric_literals);
   for (int feature = 0; feature < v8::Isolate::kUseCounterFeatureCount;
        ++feature) {
@@ -3272,57 +3271,6 @@ Handle<FixedArray> CompileTimeValue::GetElements(Handle<FixedArray> value) {
 }
 
 
-bool CheckAndCollectArrowParameter(ParserTraits* traits,
-                                   Collector<VariableProxy*>* collector,
-                                   Expression* expression) {
-  // Case for empty parameter lists:
-  //   () => ...
-  if (expression == NULL) return true;
-
-  // Too many parentheses around expression:
-  //   (( ... )) => ...
-  if (expression->parenthesization_level() > 1) return false;
-
-  // Case for a single parameter:
-  //   (foo) => ...
-  //   foo => ...
-  if (expression->IsVariableProxy()) {
-    if (expression->AsVariableProxy()->is_this()) return false;
-
-    const AstRawString* raw_name = expression->AsVariableProxy()->raw_name();
-    if (traits->IsEvalOrArguments(raw_name) ||
-        traits->IsFutureStrictReserved(raw_name))
-      return false;
-
-    collector->Add(expression->AsVariableProxy());
-    return true;
-  }
-
-  // Case for more than one parameter:
-  //   (foo, bar [, ...]) => ...
-  if (expression->IsBinaryOperation()) {
-    BinaryOperation* binop = expression->AsBinaryOperation();
-    if (binop->op() != Token::COMMA || binop->left()->is_parenthesized() ||
-        binop->right()->is_parenthesized())
-      return false;
-
-    return CheckAndCollectArrowParameter(traits, collector, binop->left()) &&
-           CheckAndCollectArrowParameter(traits, collector, binop->right());
-  }
-
-  // Any other kind of expression is not a valid parameter list.
-  return false;
-}
-
-
-Vector<VariableProxy*> ParserTraits::ParameterListFromExpression(
-    Expression* expression, bool* ok) {
-  Collector<VariableProxy*> collector;
-  *ok = CheckAndCollectArrowParameter(this, &collector, expression);
-  return collector.ToVector();
-}
-
-
 FunctionLiteral* Parser::ParseFunctionLiteral(
     const AstRawString* function_name,
     Scanner::Location function_name_location,
@@ -3732,7 +3680,6 @@ PreParser::PreParseResult Parser::ParseLazyFunctionBodyWithPreParser(
     reusable_preparser_->set_allow_lazy(true);
     reusable_preparser_->set_allow_generators(allow_generators());
     reusable_preparser_->set_allow_for_of(allow_for_of());
-    reusable_preparser_->set_allow_arrow_functions(allow_arrow_functions());
     reusable_preparser_->set_allow_harmony_numeric_literals(
         allow_harmony_numeric_literals());
   }