Separate Scope into DeclarationScope and Scope

src/parsing/parser.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/parsing/parser.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/ast/ast.h"
@@ skipping 202 matching lines @@
                                             bool call_super, int pos,
                                             int end_pos,
                                             LanguageMode language_mode) {
   int materialized_literal_count = -1;
   int expected_property_count = -1;
   int parameter_count = 0;
   if (name == nullptr) name = ast_value_factory()->empty_string();
 
   FunctionKind kind = call_super ? FunctionKind::kDefaultSubclassConstructor
                                  : FunctionKind::kDefaultBaseConstructor;
-  Scope* function_scope = NewFunctionScope(kind);
+  DeclarationScope* function_scope = NewFunctionScope(kind);
   SetLanguageMode(function_scope,
                   static_cast<LanguageMode>(language_mode | STRICT));
   // Set start and end position to the same value
   function_scope->set_start_position(pos);
   function_scope->set_end_position(pos);
   ZoneList<Statement*>* body = NULL;
 
   {
     FunctionState function_state(&function_state_, &scope_state_,
                                  function_scope, kind);
@@ skipping 711 matching lines @@
   DCHECK_NULL(scope_state_);
   DCHECK_NULL(target_stack_);
 
   Mode parsing_mode = FLAG_lazy && allow_lazy() ? PARSE_LAZILY : PARSE_EAGERLY;
   if (allow_natives() || extension_ != NULL) parsing_mode = PARSE_EAGERLY;
 
   FunctionLiteral* result = NULL;
   {
     // TODO(wingo): Add an outer SCRIPT_SCOPE corresponding to the native
     // context, which will have the "this" binding for script scopes.
-    Scope* scope = NewScriptScope();
+    DeclarationScope* scope = NewScriptScope();
     info->set_script_scope(scope);
+    Scope* inner = scope;
     if (!info->context().is_null() && !info->context()->IsNativeContext()) {
-      scope = Scope::DeserializeScopeChain(info->isolate(), zone(),
+      // If we're compiling for eval, this isn't necessarily a declaration
+      // scope.
+      inner = Scope::DeserializeScopeChain(info->isolate(), zone(),
                                            *info->context(), scope,
                                            ast_value_factory());
       // The Scope is backed up by ScopeInfo (which is in the V8 heap); this
       // means the Parser cannot operate independent of the V8 heap. Tell the
       // string table to internalize strings and values right after they're
       // created. This kind of parsing can only be done in the main thread.
       DCHECK(parsing_on_main_thread_);
       ast_value_factory()->Internalize(info->isolate());
     }
-    original_scope_ = scope;
+    original_scope_ = inner;
     if (info->is_eval()) {
-      if (!scope->is_script_scope() || is_strict(info->language_mode())) {
+      if (!inner->is_script_scope() || is_strict(info->language_mode())) {
         parsing_mode = PARSE_EAGERLY;
       }
-      scope = NewScopeWithParent(scope, EVAL_SCOPE);
+      inner = NewEvalScope(inner);
     } else if (info->is_module()) {
-      scope = NewScopeWithParent(scope, MODULE_SCOPE);
+      inner = NewModuleScope(inner);
     }
 
+    scope = inner->AsDeclarationScope();
+
     scope->set_start_position(0);
 
     // Enter 'scope' with the given parsing mode.
     ParsingModeScope parsing_mode_scope(this, parsing_mode);
     FunctionState function_state(&function_state_, &scope_state_, scope,
                                  kNormalFunction);
 
     ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(16, zone());
     bool ok = true;
     int beg_pos = scanner()->location().beg_pos;
     parsing_module_ = info->is_module();
     if (parsing_module_) {
       ParseModuleItemList(body, &ok);
       ok = ok &&
-           module()->Validate(this->scope(), &pending_error_handler_, zone());
+           module()->Validate(this->scope()->AsDeclarationScope(),
+                              &pending_error_handler_, zone());
     } else {
       // Don't count the mode in the use counters--give the program a chance
       // to enable script-wide strict mode below.
       this->scope()->SetLanguageMode(info->language_mode());
       ParseStatementList(body, Token::EOS, &ok);
     }
 
     // The parser will peek but not consume EOS.  Our scope logically goes all
     // the way to the EOS, though.
     scope->set_end_position(scanner()->peek_location().beg_pos);
 
     if (ok && is_strict(language_mode())) {
       CheckStrictOctalLiteral(beg_pos, scanner()->location().end_pos, &ok);
       CheckDecimalLiteralWithLeadingZero(use_counts_, beg_pos,
                                          scanner()->location().end_pos);
     }
     if (ok && is_sloppy(language_mode())) {
       // TODO(littledan): Function bindings on the global object that modify
       // pre-existing bindings should be made writable, enumerable and
       // nonconfigurable if possible, whereas this code will leave attributes
       // unchanged if the property already exists.
       InsertSloppyBlockFunctionVarBindings(scope, nullptr, &ok);
     }
     if (ok) {
-      CheckConflictingVarDeclarations(this->scope(), &ok);
+      CheckConflictingVarDeclarations(scope, &ok);
     }
 
     if (ok && info->parse_restriction() == ONLY_SINGLE_FUNCTION_LITERAL) {
       if (body->length() != 1 ||
           !body->at(0)->IsExpressionStatement() ||
           !body->at(0)->AsExpressionStatement()->
               expression()->IsFunctionLiteral()) {
         ReportMessage(MessageTemplate::kSingleFunctionLiteral);
         ok = false;
       }
     }
 
     if (ok) {
       ParserTraits::RewriteDestructuringAssignments();
       result = factory()->NewScriptOrEvalFunctionLiteral(
-          this->scope(), body, function_state.materialized_literal_count(),
+          scope, body, function_state.materialized_literal_count(),
           function_state.expected_property_count());
     }
   }
 
   // Make sure the target stack is empty.
   DCHECK(target_stack_ == NULL);
 
   return result;
 }
 
@@ skipping 67 matching lines @@
   const AstRawString* raw_name = ast_value_factory()->GetString(name);
   fni_->PushEnclosingName(raw_name);
 
   ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
 
   // Place holder for the result.
   FunctionLiteral* result = nullptr;
 
   {
     // Parse the function literal.
-    Scope* scope = NewScriptScope();
-    info->set_script_scope(scope);
+    DeclarationScope* script_scope = NewScriptScope();
+    Scope* scope = script_scope;
+    info->set_script_scope(script_scope);
     if (!info->context().is_null()) {
       // Ok to use Isolate here, since lazy function parsing is only done in the
       // main thread.
       DCHECK(parsing_on_main_thread_);
       scope = Scope::DeserializeScopeChain(isolate, zone(), *info->context(),
                                            scope, ast_value_factory());
     }
     original_scope_ = scope;
     FunctionState function_state(&function_state_, &scope_state_, scope,
                                  shared_info->kind());
@@ skipping 12 matching lines @@
           CHECK(stack_overflow());
           return nullptr;
         }
         if (!(peek_any_identifier() || peek() == Token::LPAREN)) {
           CHECK(stack_overflow());
           return nullptr;
         }
       }
 
       // TODO(adamk): We should construct this scope from the ScopeInfo.
-      Scope* scope = NewFunctionScope(FunctionKind::kArrowFunction);
+      DeclarationScope* scope = NewFunctionScope(FunctionKind::kArrowFunction);
 
       // These two bits only need to be explicitly set because we're
       // not passing the ScopeInfo to the Scope constructor.
       // TODO(adamk): Remove these calls once the above NewScope call
       // passes the ScopeInfo.
       if (shared_info->scope_info()->CallsEval()) {
         scope->RecordEvalCall();
       }
       SetLanguageMode(scope, shared_info->language_mode());
 
@@ skipping 761 matching lines @@
 
 
 VariableProxy* Parser::NewUnresolved(const AstRawString* name,
                                      VariableMode mode) {
   // If we are inside a function, a declaration of a 'var' variable is a
   // truly local variable, and the scope of the variable is always the function
   // scope.
   // Let/const variables are always added to the immediately enclosing scope.
   Scope* scope = IsLexicalVariableMode(mode)
                      ? this->scope()
-                     : this->scope()->DeclarationScope();
+                     : this->scope()->GetDeclarationScope();
   return scope->NewUnresolved(factory(), name, Variable::NORMAL,
                               scanner()->location().beg_pos,
                               scanner()->location().end_pos);
 }
 
 
 void Parser::DeclareImport(const AstRawString* local_name, int pos, bool* ok) {
   DCHECK_NOT_NULL(local_name);
   VariableProxy* proxy = NewUnresolved(local_name, IMPORT);
   Declaration* declaration =
       factory()->NewVariableDeclaration(proxy, IMPORT, scope(), pos);
   Declare(declaration, DeclarationDescriptor::NORMAL, true, CHECK_OK_VOID);
 }
 
 
 Variable* Parser::Declare(Declaration* declaration,
                           DeclarationDescriptor::Kind declaration_kind,
                           bool resolve, bool* ok, Scope* scope) {
   VariableProxy* proxy = declaration->proxy();
   DCHECK(proxy->raw_name() != NULL);
   const AstRawString* name = proxy->raw_name();
   VariableMode mode = declaration->mode();
   DCHECK(IsDeclaredVariableMode(mode) && mode != CONST_LEGACY);
   bool is_function_declaration = declaration->IsFunctionDeclaration();
   if (scope == nullptr) scope = this->scope();
   Scope* declaration_scope =
-      IsLexicalVariableMode(mode) ? scope : scope->DeclarationScope();
+      IsLexicalVariableMode(mode) ? scope : scope->GetDeclarationScope();
   Variable* var = NULL;
 
   // If a suitable scope exists, then we can statically declare this
   // variable and also set its mode. In any case, a Declaration node
   // will be added to the scope so that the declaration can be added
   // to the corresponding activation frame at runtime if necessary.
   // For instance, var declarations inside a sloppy eval scope need
   // to be added to the calling function context. Similarly, strict
   // mode eval scope and lexical eval bindings do not leak variable
   // declarations to the caller's scope so we declare all locals, too.
@@ skipping 21 matching lines @@
       if (is_sloppy(language_mode()) && is_function_declaration &&
           var->is_function()) {
         DCHECK(IsLexicalVariableMode(mode) &&
                IsLexicalVariableMode(var->mode()));
         // If the duplication is allowed, then the var will show up
         // in the SloppyBlockFunctionMap and the new FunctionKind
         // will be a permitted duplicate.
         FunctionKind function_kind =
             declaration->AsFunctionDeclaration()->fun()->kind();
         duplicate_allowed =
-            scope->DeclarationScope()->sloppy_block_function_map()->Lookup(
+            scope->GetDeclarationScope()->sloppy_block_function_map()->Lookup(
                 const_cast<AstRawString*>(name), name->hash()) != nullptr &&
             !IsAsyncFunction(function_kind) &&
             !(allow_harmony_restrictive_generators() &&
               IsGeneratorFunction(function_kind));
       }
       if (duplicate_allowed) {
         ++use_counts_[v8::Isolate::kSloppyModeBlockScopedFunctionRedefinition];
       } else {
         // The name was declared in this scope before; check for conflicting
         // re-declarations. We have a conflict if either of the declarations
@@ skipping 106 matching lines @@
       Expect(Token::COMMA, CHECK_OK);
     }
   }
   Expect(Token::RPAREN, CHECK_OK);
   Expect(Token::SEMICOLON, CHECK_OK);
 
   // Make sure that the function containing the native declaration
   // isn't lazily compiled. The extension structures are only
   // accessible while parsing the first time not when reparsing
   // because of lazy compilation.
-  // TODO(adamk): Should this be ClosureScope()?
-  scope()->DeclarationScope()->ForceEagerCompilation();
+  // TODO(adamk): Should this be GetClosureScope()?
+  scope()->GetDeclarationScope()->ForceEagerCompilation();
 
   // TODO(1240846): It's weird that native function declarations are
   // introduced dynamically when we meet their declarations, whereas
   // other functions are set up when entering the surrounding scope.
   VariableProxy* proxy = NewUnresolved(name, VAR);
   Declaration* declaration =
       factory()->NewVariableDeclaration(proxy, VAR, scope(), pos);
   Declare(declaration, DeclarationDescriptor::NORMAL, true, CHECK_OK);
   NativeFunctionLiteral* lit =
       factory()->NewNativeFunctionLiteral(name, extension_, kNoSourcePosition);
@@ skipping 89 matching lines @@
   EmptyStatement* empty = factory()->NewEmptyStatement(kNoSourcePosition);
   // Async functions don't undergo sloppy mode block scoped hoisting, and don't
   // allow duplicates in a block. Both are represented by the
   // sloppy_block_function_map. Don't add them to the map for async functions.
   // Generators are also supposed to be prohibited; currently doing this behind
   // a flag and UseCounting violations to assess web compatibility.
   if (is_sloppy(language_mode()) && !scope()->is_declaration_scope() &&
       !is_async && !(allow_harmony_restrictive_generators() && is_generator)) {
     SloppyBlockFunctionStatement* delegate =
         factory()->NewSloppyBlockFunctionStatement(empty, scope());
-    scope()->DeclarationScope()->sloppy_block_function_map()->Declare(
+    scope()->GetDeclarationScope()->sloppy_block_function_map()->Declare(
         variable_name, delegate);
     return delegate;
   }
   return empty;
 }
 
 Statement* Parser::ParseClassDeclaration(ZoneList<const AstRawString*>* names,
                                          bool default_export, bool* ok) {
   // ClassDeclaration ::
   //   'class' Identifier ('extends' LeftHandExpression)? '{' ClassBody '}'
@@ skipping 546 matching lines @@
   ExpectSemicolon(CHECK_OK);
 
   if (is_generator()) {
     return_value = BuildIteratorResult(return_value, true);
   } else if (is_async_function()) {
     return_value = BuildPromiseResolve(return_value, return_value->position());
   }
 
   result = factory()->NewReturnStatement(return_value, loc.beg_pos);
 
-  Scope* decl_scope = scope()->DeclarationScope();
+  DeclarationScope* decl_scope = scope()->GetDeclarationScope();
   if (decl_scope->is_script_scope() || decl_scope->is_eval_scope()) {
     ReportMessageAt(loc, MessageTemplate::kIllegalReturn);
     *ok = false;
     return NULL;
   }
   return result;
 }
 
 
 Statement* Parser::ParseWithStatement(ZoneList<const AstRawString*>* labels,
@@ skipping 1379 matching lines @@
 DoExpression* Parser::ParseDoExpression(bool* ok) {
   // AssignmentExpression ::
   //     do '{' StatementList '}'
   int pos = peek_position();
 
   Expect(Token::DO, CHECK_OK);
   Variable* result =
       scope()->NewTemporary(ast_value_factory()->dot_result_string());
   Block* block = ParseBlock(nullptr, CHECK_OK);
   DoExpression* expr = factory()->NewDoExpression(block, result, pos);
-  if (!Rewriter::Rewrite(this, scope()->ClosureScope(), expr,
+  if (!Rewriter::Rewrite(this, scope()->GetClosureScope(), expr,
                          ast_value_factory())) {
     *ok = false;
     return nullptr;
   }
   return expr;
 }
 
 void ParserTraits::ParseArrowFunctionFormalParameterList(
     ParserFormalParameters* parameters, Expression* expr,
     const Scanner::Location& params_loc, Scanner::Location* duplicate_loc,
@@ skipping 128 matching lines @@
   // - The function literal shouldn't be hinted to eagerly compile.
   // - For asm.js functions the body needs to be available when module
   //   validation is active, because we examine the entire module at once.
   bool use_temp_zone =
       !is_lazily_parsed && FLAG_lazy && !allow_natives() &&
       extension_ == NULL && allow_lazy() &&
       function_type == FunctionLiteral::kDeclaration &&
       eager_compile_hint != FunctionLiteral::kShouldEagerCompile &&
       !(FLAG_validate_asm && scope()->asm_module());
 
-  Scope* main_scope = nullptr;
+  DeclarationScope* main_scope = nullptr;
   if (use_temp_zone) {
     // This Scope lives in the main Zone; we'll migrate data into it later.
     main_scope = NewFunctionScope(kind);
   }
 
   ZoneList<Statement*>* body = nullptr;
   int arity = -1;
   int materialized_literal_count = -1;
   int expected_property_count = -1;
   DuplicateFinder duplicate_finder(scanner()->unicode_cache());
   bool should_be_used_once_hint = false;
   bool has_duplicate_parameters;
 
   {
     // Temporary zones can nest. When we migrate free variables (see below), we
     // need to recreate them in the previous Zone.
     AstNodeFactory previous_zone_ast_node_factory(ast_value_factory());
     previous_zone_ast_node_factory.set_zone(zone());
 
     // Open a new zone scope, which sets our AstNodeFactory to allocate in the
     // new temporary zone if the preconditions are satisfied, and ensures that
     // the previous zone is always restored after parsing the body. To be able
     // to do scope analysis correctly after full parsing, we migrate needed
     // information from scope into main_scope when the function has been parsed.
     Zone temp_zone(zone()->allocator());
     DiscardableZoneScope zone_scope(this, &temp_zone, use_temp_zone);
 
-    Scope* scope = NewFunctionScope(kind);
+    DeclarationScope* scope = NewFunctionScope(kind);
     SetLanguageMode(scope, language_mode);
     if (!use_temp_zone) {
       main_scope = scope;
     } else {
       DCHECK(main_scope->zone() != scope->zone());
     }
 
     FunctionState function_state(&function_state_, &scope_state_, scope, kind);
 #ifdef DEBUG
-    this->scope()->SetScopeName(function_name);
+    scope->SetScopeName(function_name);
 #endif
     ExpressionClassifier formals_classifier(this, &duplicate_finder);
 
     if (is_generator) {
       // For generators, allocating variables in contexts is currently a win
       // because it minimizes the work needed to suspend and resume an
       // activation.  The machine code produced for generators (by full-codegen)
       // relies on this forced context allocation, but not in an essential way.
       this->scope()->ForceContextAllocation();
 
@@ skipping 315 matching lines @@
           factory()->NewUndefinedLiteral(kNoSourcePosition), kNoSourcePosition);
       initial_value = factory()->NewConditional(
           condition, parameter.initializer, initial_value, kNoSourcePosition);
       descriptor.initialization_pos = parameter.initializer->position();
       initializer_position = parameter.initializer_end_position;
     }
 
     Scope* param_scope = scope();
     Block* param_block = init_block;
     if (!parameter.is_simple() && scope()->calls_sloppy_eval()) {
-      param_scope = NewScope(BLOCK_SCOPE);
-      param_scope->set_is_declaration_scope();
+      param_scope = NewVarblockScope();
       param_scope->set_start_position(descriptor.initialization_pos);
       param_scope->set_end_position(parameter.initializer_end_position);
       param_scope->RecordEvalCall();
       param_block = factory()->NewBlock(NULL, 8, true, kNoSourcePosition);
       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
@@ skipping 85 matching lines @@
     // If we have a named function expression, we add a local variable
     // declaration to the body of the function with the name of the
     // function and let it refer to the function itself (closure).
     // Not having parsed the function body, the language mode may still change,
     // so we reserve a spot and create the actual const assignment later.
     DCHECK_EQ(kFunctionNameAssignmentIndex, result->length());
     result->Add(NULL, zone());
   }
 
   ZoneList<Statement*>* body = result;
-  Scope* inner_scope = scope();
+  DeclarationScope* function_scope = scope()->AsDeclarationScope();
+  DeclarationScope* inner_scope = function_scope;
   Block* inner_block = nullptr;
   if (!parameters.is_simple) {
-    inner_scope = NewScope(BLOCK_SCOPE);
-    inner_scope->set_is_declaration_scope();
+    inner_scope = NewVarblockScope();
     inner_scope->set_start_position(scanner()->location().beg_pos);
     inner_block = factory()->NewBlock(NULL, 8, true, kNoSourcePosition);
     inner_block->set_scope(inner_scope);
     body = inner_block->statements();
   }
 
   {
     BlockState block_state(&scope_state_, inner_scope);
 
     if (IsGeneratorFunction(kind)) {
@@ skipping 65 matching lines @@
                     kNoSourcePosition),
                 zone());
     }
   }
 
   Expect(Token::RBRACE, CHECK_OK);
   scope()->set_end_position(scanner()->location().end_pos);
 
   if (!parameters.is_simple) {
     DCHECK_NOT_NULL(inner_scope);
+    DCHECK_EQ(function_scope, scope());
+    DCHECK_EQ(function_scope, inner_scope->outer_scope());
     DCHECK_EQ(body, inner_block->statements());
-    SetLanguageMode(scope(), inner_scope->language_mode());
+    SetLanguageMode(function_scope, inner_scope->language_mode());
     Block* init_block = BuildParameterInitializationBlock(parameters, CHECK_OK);
 
     if (is_sloppy(inner_scope->language_mode())) {
-      InsertSloppyBlockFunctionVarBindings(
-          inner_scope, inner_scope->outer_scope(), CHECK_OK);
+      InsertSloppyBlockFunctionVarBindings(inner_scope, function_scope,
+                                           CHECK_OK);
     }
 
     if (IsAsyncFunction(kind)) {
       init_block = BuildRejectPromiseOnException(init_block);
     }
 
     DCHECK_NOT_NULL(init_block);
 
     inner_scope->set_end_position(scanner()->location().end_pos);
-    inner_scope = inner_scope->FinalizeBlockScope();

[adamk, 2016/08/04 00:18:51]

I don't think it's worth changing this, there's some advantage to any further
attempts to touch a finalized scope crashing instead of continuing silently (it
also seems unrelated to this patch).

[Toon Verwaest, 2016/08/04 12:01:17]

inner_scope is a DeclarationScope, and FinalizeBlockScope returns a Scope*. I
now explicitly null out inner_scope to guarantee we don't use it at all
afterwards.

-    if (inner_scope != nullptr) {
+    if (inner_scope->FinalizeBlockScope() != nullptr) {
       CheckConflictingVarDeclarations(inner_scope, CHECK_OK);
       InsertShadowingVarBindingInitializers(inner_block);
     }
 
     result->Add(init_block, zone());
     result->Add(inner_block, zone());
   } else {
-    if (is_sloppy(inner_scope->language_mode())) {
-      InsertSloppyBlockFunctionVarBindings(inner_scope, nullptr, CHECK_OK);
+    DCHECK_EQ(inner_scope, function_scope);
+    if (is_sloppy(function_scope->language_mode())) {
+      InsertSloppyBlockFunctionVarBindings(function_scope, nullptr, CHECK_OK);
     }
   }
 
   if (function_type == FunctionLiteral::kNamedExpression) {
     // Now that we know the language mode, we can create the const assignment
     // in the previously reserved spot.
     // NOTE: We create a proxy and resolve it here so that in the
     // future we can change the AST to only refer to VariableProxies
     // instead of Variables and Proxies as is the case now.
+    DCHECK_EQ(function_scope, scope());
     VariableMode fvar_mode = is_strict(language_mode()) ? CONST : CONST_LEGACY;
     Variable* fvar = new (zone())
         Variable(scope(), function_name, fvar_mode, Variable::NORMAL,
                  kCreatedInitialized, kNotAssigned);
     VariableProxy* proxy = factory()->NewVariableProxy(fvar);
     VariableDeclaration* fvar_declaration = factory()->NewVariableDeclaration(
         proxy, fvar_mode, scope(), kNoSourcePosition);
-    scope()->DeclareFunctionVar(fvar_declaration);
+    function_scope->DeclareFunctionVar(fvar_declaration);
 
     VariableProxy* fproxy = factory()->NewVariableProxy(fvar);
     result->Set(kFunctionNameAssignmentIndex,
                 factory()->NewExpressionStatement(
                     factory()->NewAssignment(Token::INIT, fproxy,
                                              factory()->NewThisFunction(pos),
                                              kNoSourcePosition),
                     kNoSourcePosition));
   }
 
@@ skipping 23 matching lines @@
     SET_ALLOW(harmony_for_in);
     SET_ALLOW(harmony_function_sent);
     SET_ALLOW(harmony_exponentiation_operator);
     SET_ALLOW(harmony_restrictive_declarations);
     SET_ALLOW(harmony_async_await);
     SET_ALLOW(harmony_trailing_commas);
 #undef SET_ALLOW
   }
   PreParser::PreParseResult result = reusable_preparser_->PreParseLazyFunction(
       language_mode(), function_state_->kind(),
-      scope()->has_simple_parameters(), parsing_module_, logger, bookmark,
-      use_counts_);
+      scope()->AsDeclarationScope()->has_simple_parameters(), parsing_module_,
+      logger, bookmark, use_counts_);
   if (pre_parse_timer_ != NULL) {
     pre_parse_timer_->Stop();
   }
   return result;
 }
 
 Expression* Parser::ParseClassLiteral(ExpressionClassifier* classifier,
                                       const AstRawString* name,
                                       Scanner::Location class_name_location,
                                       bool name_is_strict_reserved, int pos,
@@ skipping 105 matching lines @@
       scope()->NewTemporary(ast_value_factory()->empty_string());
   do_block->set_scope(block_state.FinalizedBlockScope());
   DoExpression* do_expr = factory()->NewDoExpression(do_block, result_var, pos);
 
   ClassLiteral* class_literal = factory()->NewClassLiteral(
       proxy, extends, constructor, properties, pos, end_pos);
 
   do_block->statements()->Add(
       factory()->NewExpressionStatement(class_literal, pos), zone());
   do_expr->set_represented_function(constructor);
-  Rewriter::Rewrite(this, scope()->ClosureScope(), do_expr,
+  Rewriter::Rewrite(this, scope()->GetClosureScope(), do_expr,
                     ast_value_factory());
 
   return do_expr;
 }
 
 
 Expression* Parser::ParseV8Intrinsic(bool* ok) {
   // CallRuntime ::
   //   '%' Identifier Arguments
 
   int pos = peek_position();
   Expect(Token::MOD, CHECK_OK);
   // Allow "eval" or "arguments" for backward compatibility.
   const AstRawString* name = ParseIdentifier(kAllowRestrictedIdentifiers,
                                              CHECK_OK);
   Scanner::Location spread_pos;
   ExpressionClassifier classifier(this);
   ZoneList<Expression*>* args =
       ParseArguments(&spread_pos, &classifier, CHECK_OK);
 
   DCHECK(!spread_pos.IsValid());
 
   if (extension_ != NULL) {
     // The extension structures are only accessible while parsing the
     // very first time not when reparsing because of lazy compilation.
-    scope()->DeclarationScope()->ForceEagerCompilation();
+    scope()->GetDeclarationScope()->ForceEagerCompilation();
   }
 
   const Runtime::Function* function = Runtime::FunctionForName(name->string());
 
   if (function != NULL) {
     // Check for possible name clash.
     DCHECK_EQ(Context::kNotFound,
               Context::IntrinsicIndexForName(name->string()));
     // Check for built-in IS_VAR macro.
     if (function->function_id == Runtime::kIS_VAR) {
@@ skipping 72 matching lines @@
     VariableProxy* to = inner_scope->NewUnresolved(factory(), name);
     VariableProxy* from = factory()->NewVariableProxy(parameter);
     Expression* assignment =
         factory()->NewAssignment(Token::ASSIGN, to, from, kNoSourcePosition);
     Statement* statement =
         factory()->NewExpressionStatement(assignment, kNoSourcePosition);
     inner_block->statements()->InsertAt(0, statement, zone());
   }
 }
 
-void Parser::InsertSloppyBlockFunctionVarBindings(Scope* scope,
+void Parser::InsertSloppyBlockFunctionVarBindings(DeclarationScope* scope,
                                                   Scope* complex_params_scope,
                                                   bool* ok) {
   // For each variable which is used as a function declaration in a sloppy
   // block,
-  DCHECK(scope->is_declaration_scope());
   SloppyBlockFunctionMap* map = scope->sloppy_block_function_map();
   for (ZoneHashMap::Entry* p = map->Start(); p != nullptr; p = map->Next(p)) {
     AstRawString* name = static_cast<AstRawString*>(p->key);
 
     // If the variable wouldn't conflict with a lexical declaration
     // or parameter,
 
     // Check if there's a conflict with a parameter.
     // This depends on the fact that functions always have a scope solely to
     // hold complex parameters, and the names local to that scope are
@@ skipping 11 matching lines @@
         continue;
       }
     }
 
     bool var_created = false;
 
     // Write in assignments to var for each block-scoped function declaration
     auto delegates = static_cast<SloppyBlockFunctionMap::Vector*>(p->value);
     for (SloppyBlockFunctionStatement* delegate : *delegates) {
       // Check if there's a conflict with a lexical declaration
-      Scope* decl_scope = scope;
+      DeclarationScope* decl_scope = scope;
       while (decl_scope->is_eval_scope()) {
-        decl_scope = decl_scope->outer_scope()->DeclarationScope();
+        decl_scope = decl_scope->outer_scope()->GetDeclarationScope();
       }
       Scope* outer_scope = decl_scope->outer_scope();
       Scope* query_scope = delegate->scope()->outer_scope();
       Variable* var = nullptr;
       bool should_hoist = true;
 
       // Note that we perform this loop for each delegate named 'name',
       // which may duplicate work if those delegates share scopes.
       // It is not sufficient to just do a Lookup on query_scope: for
       // example, that does not prevent hoisting of the function in
@@ skipping 1331 matching lines @@
     do_block_->statements()->Add(validate_iterator, zone);
     do_block_->statements()->Add(loop, zone);
     do_block_->statements()->Add(maybe_return_value, zone);
 
     Block* do_block = factory->NewBlock(nullptr, 2, false, nopos);
     do_block->statements()->Add(do_block_, zone);
     do_block->statements()->Add(get_value, zone);
 
     Variable* dot_result = scope->NewTemporary(avfactory->dot_result_string());
     yield_star = factory->NewDoExpression(do_block, dot_result, nopos);
-    Rewriter::Rewrite(parser_, scope->ClosureScope(), yield_star, avfactory);
+    Rewriter::Rewrite(parser_, scope->GetClosureScope(), yield_star, avfactory);
   }
 
   return yield_star;
 }
 
 Statement* ParserTraits::CheckCallable(Variable* var, Expression* error,
                                        int pos) {
   auto factory = parser_->factory();
   auto avfactory = parser_->ast_value_factory();
   const int nopos = kNoSourcePosition;
@@ skipping 456 matching lines @@
   node->Print(Isolate::Current());
 }
 #endif  // DEBUG
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8