Move function length tracking from Scope to (Pre)?ParserFormalParameters.

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 <set>
 
 #include "src/accessors.h"
 #include "src/ast/ast.h"
@@ skipping 253 matching lines @@
   asm_function_ = false;
   force_eager_compilation_ = false;
   has_arguments_parameter_ = false;
   scope_uses_super_property_ = false;
   has_rest_ = false;
   receiver_ = nullptr;
   new_target_ = nullptr;
   function_ = nullptr;
   arguments_ = nullptr;
   this_function_ = nullptr;
-  arity_ = 0;
 }
 
 void Scope::SetDefaults() {
 #ifdef DEBUG
   scope_name_ = nullptr;
   already_resolved_ = false;
   needs_migration_ = false;
 #endif
   inner_scope_ = nullptr;
   sibling_ = nullptr;
@@ skipping 548 matching lines @@
   DCHECK(!is_optional || !is_rest);
   Variable* var;
   if (mode == TEMPORARY) {
     var = NewTemporary(name);
   } else {
     var =
         Declare(zone(), this, name, mode, NORMAL_VARIABLE, kCreatedInitialized);
     // TODO(wingo): Avoid O(n^2) check.
     *is_duplicate = IsDeclaredParameter(name);
   }
-  if (!is_optional && !is_rest && arity_ == params_.length()) {
-    ++arity_;
-  }
   has_rest_ = is_rest;
   params_.Add(var, zone());
   if (name == ast_value_factory->arguments_string()) {
     has_arguments_parameter_ = true;
   }
   return var;
 }
 
 Variable* Scope::DeclareLocal(const AstRawString* name, VariableMode mode,
                               InitializationFlag init_flag, VariableKind kind,
@@ skipping 1089 matching lines @@
   Variable* function =
       is_function_scope() ? AsDeclarationScope()->function_var() : nullptr;
   bool is_function_var_in_context =
       function != nullptr && function->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
          (is_function_var_in_context ? 1 : 0);
 }
 
 }  // namespace internal
 }  // namespace v8