Revert of Rewrite scopes of non-simple default arguments (patchset #5 id:80001...

Revert of Rewrite scopes of non-simple default arguments (patchset #5 id:80001 of https://codereview.chromium.org/2077283004/ )

Reason for revert:
Seems to close tree (but it could be an infra issue)

Original issue's description:
> Rewrite scopes of non-simple default arguments
>
> Default parameters have additional declaration block scopes inserted
> around them when something in the function scope calls eval. This
> patch sets the parent scope of the expressions introduced due to
> those defaults to the new block scope.
>
> R=adamk
> BUG=chromium:616386
>
> Committed: https://crrev.com/0e14baf712955a1993f742647bb2adc293702b80
> Cr-Commit-Position: refs/heads/master@{#37198}

TBR=adamk@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:616386

Review-Url: https://codereview.chromium.org/2081323006
Cr-Commit-Position: refs/heads/master@{#37201}

src/parsing/parameter-initializer-rewriter.cc

@@ -90,10 +90,6 @@ void Rewriter::VisitVariableProxy(VariableProxy* proxy) {
   if (proxy->is_resolved()) {
     Variable* var = proxy->var();
     if (var->mode() != TEMPORARY) return;
-    // For rewriting inside the same ClosureScope (e.g., putting default
-    // parameter values in their own inner scope in certain cases), refrain
-    // from invalidly moving temporaries to a block scope.
-    if (var->scope()->ClosureScope() == new_scope_->ClosureScope()) return;
     int index = old_scope_->RemoveTemporary(var);
     if (index >= 0) {
       temps_.push_back(std::make_pair(var, index));

src/parsing/parser.cc

@@ -4614,12 +4614,6 @@ Block* Parser::BuildParameterInitializationBlock(
       param_block = factory()->NewBlock(NULL, 8, true, RelocInfo::kNoPosition);
       param_block->set_scope(param_scope);
       descriptor.hoist_scope = scope_;
-      // Pass the appropriate scope in so that PatternRewriter can appropriately
-      // rewrite inner initializers of the pattern to param_scope
-      descriptor.scope = param_scope;
-      // Rewrite the outer initializer to point to param_scope
-      RewriteParameterInitializerScope(stack_limit(), initial_value, scope_,
-                                       param_scope);
     }
 
     {

src/parsing/pattern-rewriter.cc

@@ -677,29 +677,9 @@ void Parser::PatternRewriter::VisitAssignment(Assignment* node) {
                                       RelocInfo::kNoPosition);
   }
 
-  // Two cases for scope rewriting the scope of default parameters:
-  // - Eagerly parsed arrow functions are initially parsed as having
-  //   initializers in the enclosing scope, but when the arrow is encountered,
-  //   need to be in the scope of the function.
-  // - When an extra declaration scope needs to be inserted to account for
-  //   a sloppy eval in a default parameter or function body, the initializer
-  //   needs to be in that new inner scope which was added after initial
-  //   parsing.
-  // Each of these cases can be handled by rewriting the contents of the
-  // initializer to the current scope. The source scope is typically the outer
-  // scope when one case occurs; when both cases occur, both scopes need to
-  // be included as the outer scope. (Both rewritings still need to be done
-  // to account for lazily parsed arrow functions which hit the second case.)
-  // TODO(littledan): Remove the outer_scope parameter of
-  //                  RewriteParameterInitializerScope
   if (IsBindingContext() &&
       descriptor_->declaration_kind == DeclarationDescriptor::PARAMETER &&
-      (scope()->is_arrow_scope() || scope()->is_block_scope())) {
-    if (scope()->outer_scope()->is_arrow_scope() && scope()->is_block_scope()) {
-      RewriteParameterInitializerScope(parser_->stack_limit(), initializer,
-                                       scope()->outer_scope()->outer_scope(),
-                                       scope());
-    }
+      scope()->is_arrow_scope()) {
     RewriteParameterInitializerScope(parser_->stack_limit(), initializer,
                                      scope()->outer_scope(), scope());
   }

test/mjsunit/regress/regress-616386.js

-// Copyright 2016 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.
-
-// Flags: --no-lazy
-
-assertEquals(0, ((y = (function(a2) { bbbb = a2 }), bbbb = eval('1')) => {y(0); return bbbb})())
-assertEquals(0, (({y = (function(a2) { bbbb = a2 }), bbbb = eval('1')} = {}) => {y(0); return bbbb})())
-assertEquals(0, (function (y = (function(a2) { bbbb = a2 }), bbbb = eval('1')) {y(0); return bbbb})())
-assertEquals(0, (function ({y = (function(a2) { bbbb = a2 }), bbbb = eval('1')} = {}) {y(0); return bbbb})())