Partial revert of rest parameter desugaring.

src/ast/scopes.cc

 // Copyright 2012 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/ast/scopes.h"
 
 #include "src/accessors.h"
 #include "src/ast/scopeinfo.h"
 #include "src/bootstrapper.h"
 #include "src/messages.h"
@@ skipping 187 matching lines @@
   force_eager_compilation_ = false;
   force_context_allocation_ = (outer_scope != NULL && !is_function_scope())
       ? outer_scope->has_forced_context_allocation() : false;
   num_var_or_const_ = 0;
   num_stack_slots_ = 0;
   num_heap_slots_ = 0;
   num_global_slots_ = 0;
   arity_ = 0;
   has_simple_parameters_ = true;
   rest_parameter_ = NULL;
+  rest_index_ = -1;
   scope_info_ = scope_info;
   start_position_ = RelocInfo::kNoPosition;
   end_position_ = RelocInfo::kNoPosition;
   if (!scope_info.is_null()) {
     scope_calls_eval_ = scope_info->CallsEval();
     language_mode_ = scope_info->language_mode();
     is_declaration_scope_ = scope_info->is_declaration_scope();
     function_kind_ = scope_info->function_kind();
   }
 }
@@ skipping 296 matching lines @@
                              kCreatedInitialized);
     // TODO(wingo): Avoid O(n^2) check.
     *is_duplicate = IsDeclaredParameter(name);
   }
   if (!is_optional && !is_rest && arity_ == params_.length()) {
     ++arity_;
   }
   if (is_rest) {
     DCHECK_NULL(rest_parameter_);
     rest_parameter_ = var;
+    rest_index_ = num_parameters();
   }
   params_.Add(var, zone());
   return var;
 }
 
 
 Variable* Scope::DeclareLocal(const AstRawString* name, VariableMode mode,
                               InitializationFlag init_flag, Variable::Kind kind,
                               MaybeAssignedFlag maybe_assigned_flag,
                               int declaration_group_start) {
@@ skipping 1140 matching lines @@
       function_ != NULL && function_->proxy()->var()->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS - num_global_slots() -
          (is_function_var_in_context ? 1 : 0);
 }
 
 
 int Scope::ContextGlobalCount() const { return num_global_slots(); }
 
 }  // namespace internal
 }  // namespace v8