Revert of [es6] Fix scoping for default parameters in arrow functions

src/parameter-initializer-rewriter.cc

-// Copyright 2015 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 "src/v8.h"
-
-#include "src/parameter-initializer-rewriter.h"
-
-#include "src/ast.h"
-#include "src/ast-expression-visitor.h"
-#include "src/scopes.h"
-
-namespace v8 {
-namespace internal {
-
-namespace {
-
-
-class Rewriter final : public AstExpressionVisitor {
- public:
-  Rewriter(uintptr_t stack_limit, Expression* initializer, Scope* old_scope,
-           Scope* new_scope)
-      : AstExpressionVisitor(stack_limit, initializer),
-        old_scope_(old_scope),
-        new_scope_(new_scope) {}
-
- private:
-  void VisitExpression(Expression* expr) override {}
-
-  void VisitFunctionLiteral(FunctionLiteral* expr) override;
-  void VisitClassLiteral(ClassLiteral* expr) override;
-  void VisitVariableProxy(VariableProxy* expr) override;
-
-  Scope* old_scope_;
-  Scope* new_scope_;
-};
-
-
-void Rewriter::VisitFunctionLiteral(FunctionLiteral* function_literal) {
-  function_literal->scope()->set_outer_scope(new_scope_);
-}
-
-
-void Rewriter::VisitClassLiteral(ClassLiteral* class_literal) {
-  class_literal->scope()->set_outer_scope(new_scope_);
-  if (class_literal->extends() != nullptr) {
-    Visit(class_literal->extends());
-  }
-  // No need to visit the constructor since it will have the class
-  // scope on its scope chain.
-  ZoneList<ObjectLiteralProperty*>* props = class_literal->properties();
-  for (int i = 0; i < props->length(); ++i) {
-    ObjectLiteralProperty* prop = props->at(i);
-    if (!prop->key()->IsLiteral()) {
-      Visit(prop->key());
-    }
-    // No need to visit the values, since all values are functions with
-    // the class scope on their scope chain.
-    DCHECK(prop->value()->IsFunctionLiteral());
-  }
-}
-
-
-void Rewriter::VisitVariableProxy(VariableProxy* proxy) {
-  DCHECK(!proxy->is_resolved());
-  if (old_scope_->RemoveUnresolved(proxy)) {
-    new_scope_->AddUnresolved(proxy);
-  }
-}
-
-
-}  // anonymous namespace
-
-
-void RewriteParameterInitializerScope(uintptr_t stack_limit,
-                                      Expression* initializer, Scope* old_scope,
-                                      Scope* new_scope) {
-  Rewriter rewriter(stack_limit, initializer, old_scope, new_scope);
-  rewriter.Run();
-}
-
-
-}  // namespace internal
-}  // namespace v8