diff --git a/src/ast/ast.h b/src/ast/ast.h
index 7f00955..dcb440d 100644
--- a/src/ast/ast.h
+++ b/src/ast/ast.h
@@ -91,7 +91,7 @@
   V(CaseClause)                 \
   V(EmptyParentheses)           \
   V(DoExpression)               \
-  V(RewritableAssignmentExpression)
+  V(RewritableExpression)
 
 #define AST_NODE_LIST(V)                        \
   DECLARATION_NODE_LIST(V)                      \
@@ -196,15 +196,18 @@
   virtual NodeType node_type() const = 0;
   int position() const { return position_; }
 
+#ifdef DEBUG
+  void PrettyPrint(Isolate* isolate);
+  void PrettyPrint();
+  void Print(Isolate* isolate);
+  void Print();
+#endif  // DEBUG
+
   // Type testing & conversion functions overridden by concrete subclasses.
 #define DECLARE_NODE_FUNCTIONS(type) \
-  bool Is##type() const { return node_type() == AstNode::k##type; } \
-  type* As##type() { \
-    return Is##type() ? reinterpret_cast<type*>(this) : NULL; \
-  } \
-  const type* As##type() const { \
-    return Is##type() ? reinterpret_cast<const type*>(this) : NULL; \
-  }
+  V8_INLINE bool Is##type() const;   \
+  V8_INLINE type* As##type();        \
+  V8_INLINE const type* As##type() const;
   AST_NODE_LIST(DECLARE_NODE_FUNCTIONS)
 #undef DECLARE_NODE_FUNCTIONS
 
@@ -237,7 +240,6 @@
 
   bool IsEmpty() { return AsEmptyStatement() != NULL; }
   virtual bool IsJump() const { return false; }
-  virtual void MarkTail() {}
 };
 
 
@@ -317,6 +319,10 @@
   // names because [] for string objects is handled only by keyed ICs.
   virtual bool IsPropertyName() const { return false; }
 
+  // True iff the expression is a class or function expression without
+  // a syntactic name.
+  virtual bool IsAnonymousFunctionDefinition() const { return false; }
+
   // True iff the expression is a literal represented as a smi.
   bool IsSmiLiteral() const;
 
@@ -365,14 +371,6 @@
   BailoutId id() const { return BailoutId(local_id(0)); }
   TypeFeedbackId test_id() const { return TypeFeedbackId(local_id(1)); }
 
-  // Parenthesized expressions in the form `( Expression )`.
-  void set_is_parenthesized() {
-    bit_field_ = ParenthesizedField::update(bit_field_, true);
-  }
-  bool is_parenthesized() const {
-    return ParenthesizedField::decode(bit_field_);
-  }
-
  protected:
   Expression(Zone* zone, int pos)
       : AstNode(pos),
@@ -395,8 +393,6 @@
   int base_id_;
   Bounds bounds_;
   class ToBooleanTypesField : public BitField16<uint16_t, 0, 9> {};
-  class ParenthesizedField
-      : public BitField16<bool, ToBooleanTypesField::kNext, 1> {};
   uint16_t bit_field_;
   // Ends with 16-bit field; deriving classes in turn begin with
   // 16-bit fields for optimum packing efficiency.
@@ -471,10 +467,6 @@
         && labels() == NULL;  // Good enough as an approximation...
   }
 
-  void MarkTail() override {
-    if (!statements_.is_empty()) statements_.last()->MarkTail();
-  }
-
   Scope* scope() const { return scope_; }
   void set_scope(Scope* scope) { scope_ = scope; }
 
@@ -505,8 +497,6 @@
   VariableProxy* result() { return result_; }
   void set_result(VariableProxy* v) { result_ = v; }
 
-  void MarkTail() override { block_->MarkTail(); }
-
  protected:
   DoExpression(Zone* zone, Block* block, VariableProxy* result, int pos)
       : Expression(zone, pos), block_(block), result_(result) {
@@ -555,24 +545,10 @@
     return mode() == VAR ? kCreatedInitialized : kNeedsInitialization;
   }
 
-  bool is_class_declaration() const { return is_class_declaration_; }
-
-  // VariableDeclarations can be grouped into consecutive declaration
-  // groups. Each VariableDeclaration is associated with the start position of
-  // the group it belongs to. The positions are used for strong mode scope
-  // checks for classes and functions.
-  int declaration_group_start() const { return declaration_group_start_; }
-
  protected:
   VariableDeclaration(Zone* zone, VariableProxy* proxy, VariableMode mode,
-                      Scope* scope, int pos, bool is_class_declaration = false,
-                      int declaration_group_start = -1)
-      : Declaration(zone, proxy, mode, scope, pos),
-        is_class_declaration_(is_class_declaration),
-        declaration_group_start_(declaration_group_start) {}
-
-  bool is_class_declaration_;
-  int declaration_group_start_;
+                      Scope* scope, int pos)
+      : Declaration(zone, proxy, mode, scope, pos) {}
 };
 
 
@@ -820,6 +796,10 @@
                                  FeedbackVectorSlotCache* cache) override;
   FeedbackVectorSlot EachFeedbackSlot() const { return each_slot_; }
 
+  static const char* VisitModeString(VisitMode mode) {
+    return mode == ITERATE ? "for-of" : "for-in";
+  }
+
  protected:
   ForEachStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
       : IterationStatement(zone, labels, pos), each_(NULL), subject_(NULL) {}
@@ -857,9 +837,9 @@
 
   static int num_ids() { return parent_num_ids() + 6; }
   BailoutId BodyId() const { return BailoutId(local_id(0)); }
-  BailoutId PrepareId() const { return BailoutId(local_id(1)); }
-  BailoutId EnumId() const { return BailoutId(local_id(2)); }
-  BailoutId ToObjectId() const { return BailoutId(local_id(3)); }
+  BailoutId EnumId() const { return BailoutId(local_id(1)); }
+  BailoutId ToObjectId() const { return BailoutId(local_id(2)); }
+  BailoutId PrepareId() const { return BailoutId(local_id(3)); }
   BailoutId FilterId() const { return BailoutId(local_id(4)); }
   BailoutId AssignmentId() const { return BailoutId(local_id(5)); }
   BailoutId ContinueId() const override { return EntryId(); }
@@ -885,11 +865,13 @@
   void Initialize(Expression* each,
                   Expression* subject,
                   Statement* body,
+                  Variable* iterator,
                   Expression* assign_iterator,
                   Expression* next_result,
                   Expression* result_done,
                   Expression* assign_each) {
     ForEachStatement::Initialize(each, subject, body);
+    iterator_ = iterator;
     assign_iterator_ = assign_iterator;
     next_result_ = next_result;
     result_done_ = result_done;
@@ -900,6 +882,10 @@
     return subject();
   }
 
+  Variable* iterator() const {
+    return iterator_;
+  }
+
   // iterator = subject[Symbol.iterator]()
   Expression* assign_iterator() const {
     return assign_iterator_;
@@ -934,6 +920,7 @@
  protected:
   ForOfStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
       : ForEachStatement(zone, labels, pos),
+        iterator_(NULL),
         assign_iterator_(NULL),
         next_result_(NULL),
         result_done_(NULL),
@@ -943,6 +930,7 @@
  private:
   int local_id(int n) const { return base_id() + parent_num_ids() + n; }
 
+  Variable* iterator_;
   Expression* assign_iterator_;
   Expression* next_result_;
   Expression* result_done_;
@@ -957,7 +945,6 @@
   void set_expression(Expression* e) { expression_ = e; }
   Expression* expression() const { return expression_; }
   bool IsJump() const override { return expression_->IsThrow(); }
-  void MarkTail() override { expression_->MarkTail(); }
 
  protected:
   ExpressionStatement(Zone* zone, Expression* expression, int pos)
@@ -1039,8 +1026,6 @@
   BailoutId ToObjectId() const { return BailoutId(local_id(0)); }
   BailoutId EntryId() const { return BailoutId(local_id(1)); }
 
-  void MarkTail() override { statement_->MarkTail(); }
-
  protected:
   WithStatement(Zone* zone, Scope* scope, Expression* expression,
                 Statement* statement, int pos)
@@ -1083,10 +1068,6 @@
   BailoutId EntryId() const { return BailoutId(local_id(0)); }
   TypeFeedbackId CompareId() { return TypeFeedbackId(local_id(1)); }
 
-  void MarkTail() override {
-    if (!statements_->is_empty()) statements_->last()->MarkTail();
-  }
-
   Type* compare_type() { return compare_type_; }
   void set_compare_type(Type* type) { compare_type_ = type; }
 
@@ -1119,10 +1100,6 @@
 
   void set_tag(Expression* t) { tag_ = t; }
 
-  void MarkTail() override {
-    if (!cases_->is_empty()) cases_->last()->MarkTail();
-  }
-
  protected:
   SwitchStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
       : BreakableStatement(zone, labels, TARGET_FOR_ANONYMOUS, pos),
@@ -1160,11 +1137,6 @@
         && HasElseStatement() && else_statement()->IsJump();
   }
 
-  void MarkTail() override {
-    then_statement_->MarkTail();
-    else_statement_->MarkTail();
-  }
-
   void set_base_id(int id) { base_id_ = id; }
   static int num_ids() { return parent_num_ids() + 3; }
   BailoutId IfId() const { return BailoutId(local_id(0)); }
@@ -1201,27 +1173,12 @@
   Block* try_block() const { return try_block_; }
   void set_try_block(Block* b) { try_block_ = b; }
 
-  void set_base_id(int id) { base_id_ = id; }
-  static int num_ids() { return parent_num_ids() + 1; }
-  BailoutId HandlerId() const { return BailoutId(local_id(0)); }
-
  protected:
   TryStatement(Zone* zone, Block* try_block, int pos)
-      : Statement(zone, pos),
-        try_block_(try_block),
-        base_id_(BailoutId::None().ToInt()) {}
-  static int parent_num_ids() { return 0; }
-
-  int base_id() const {
-    DCHECK(!BailoutId(base_id_).IsNone());
-    return base_id_;
-  }
+      : Statement(zone, pos), try_block_(try_block) {}
 
  private:
-  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
-
   Block* try_block_;
-  int base_id_;
 };
 
 
@@ -1234,8 +1191,6 @@
   Block* catch_block() const { return catch_block_; }
   void set_catch_block(Block* b) { catch_block_ = b; }
 
-  void MarkTail() override { catch_block_->MarkTail(); }
-
  protected:
   TryCatchStatement(Zone* zone, Block* try_block, Scope* scope,
                     Variable* variable, Block* catch_block, int pos)
@@ -1258,8 +1213,6 @@
   Block* finally_block() const { return finally_block_; }
   void set_finally_block(Block* b) { finally_block_ = b; }
 
-  void MarkTail() override { finally_block_->MarkTail(); }
-
  protected:
   TryFinallyStatement(Zone* zone, Block* try_block, Block* finally_block,
                       int pos)
@@ -1472,6 +1425,8 @@
 
   void set_receiver_type(Handle<Map> map) { receiver_type_ = map; }
 
+  bool NeedsSetFunctionName() const;
+
  protected:
   friend class AstNodeFactory;
 
@@ -1510,6 +1465,9 @@
   bool may_store_doubles() const { return may_store_doubles_; }
   bool has_function() const { return has_function_; }
   bool has_elements() const { return has_elements_; }
+  bool has_shallow_properties() const {
+    return depth() == 1 && !has_elements() && !may_store_doubles();
+  }
 
   // Decide if a property should be in the object boilerplate.
   static bool IsBoilerplateProperty(Property* property);
@@ -1526,7 +1484,7 @@
   int ComputeFlags(bool disable_mementos = false) const {
     int flags = fast_elements() ? kFastElements : kNoFlags;
     flags |= has_function() ? kHasFunction : kNoFlags;
-    if (depth() == 1 && !has_elements() && !may_store_doubles()) {
+    if (has_shallow_properties()) {
       flags |= kShallowProperties;
     }
     if (disable_mementos) {
@@ -1683,6 +1641,19 @@
     return flags;
   }
 
+  // Provide a mechanism for iterating through values to rewrite spreads.
+  ZoneList<Expression*>::iterator FirstSpread() const {
+    return (first_spread_index_ >= 0) ? values_->begin() + first_spread_index_
+                                      : values_->end();
+  }
+  ZoneList<Expression*>::iterator EndValue() const { return values_->end(); }
+
+  // Rewind an array literal omitting everything from the first spread on.
+  void RewindSpreads() {
+    values_->Rewind(first_spread_index_);
+    first_spread_index_ = -1;
+  }
+
   enum Flags {
     kNoFlags = 0,
     kShallowElements = 1,
@@ -1975,7 +1946,10 @@
     bit_field_ = IsUninitializedField::update(bit_field_, b);
   }
 
-  bool is_tail() const { return IsTailField::decode(bit_field_); }
+  TailCallMode tail_call_mode() const {
+    return IsTailField::decode(bit_field_) ? TailCallMode::kAllow
+                                           : TailCallMode::kDisallow;
+  }
   void MarkTail() override {
     bit_field_ = IsTailField::update(bit_field_, true);
   }
@@ -2349,7 +2323,7 @@
         op_(op),
         left_(left),
         right_(right),
-        combined_type_(Type::None(zone)) {
+        combined_type_(Type::None()) {
     DCHECK(Token::IsCompareOp(op));
   }
   static int parent_num_ids() { return Expression::num_ids(); }
@@ -2372,17 +2346,20 @@
   Expression* expression() const { return expression_; }
   void set_expression(Expression* e) { expression_ = e; }
 
+  int expression_position() const { return expr_pos_; }
+
   static int num_ids() { return parent_num_ids(); }
 
  protected:
-  Spread(Zone* zone, Expression* expression, int pos)
-      : Expression(zone, pos), expression_(expression) {}
+  Spread(Zone* zone, Expression* expression, int pos, int expr_pos)
+      : Expression(zone, pos), expression_(expression), expr_pos_(expr_pos) {}
   static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
   int local_id(int n) const { return base_id() + parent_num_ids() + n; }
 
   Expression* expression_;
+  int expr_pos_;
 };
 
 
@@ -2505,18 +2482,32 @@
 };
 
 
-class RewritableAssignmentExpression : public Expression {
+// The RewritableExpression class is a wrapper for AST nodes that wait
+// for some potential rewriting.  However, even if such nodes are indeed
+// rewritten, the RewritableExpression wrapper nodes will survive in the
+// final AST and should be just ignored, i.e., they should be treated as
+// equivalent to the wrapped nodes.  For this reason and to simplify later
+// phases, RewritableExpressions are considered as exceptions of AST nodes
+// in the following sense:
+//
+// 1. IsRewritableExpression and AsRewritableExpression behave as usual.
+// 2. All other Is* and As* methods are practically delegated to the
+//    wrapped node, i.e. IsArrayLiteral() will return true iff the
+//    wrapped node is an array literal.
+//
+// Furthermore, an invariant that should be respected is that the wrapped
+// node is not a RewritableExpression.
+class RewritableExpression : public Expression {
  public:
-  DECLARE_NODE_TYPE(RewritableAssignmentExpression)
+  DECLARE_NODE_TYPE(RewritableExpression)
 
-  Expression* expression() { return expr_; }
+  Expression* expression() const { return expr_; }
   bool is_rewritten() const { return is_rewritten_; }
 
-  void set_expression(Expression* e) { expr_ = e; }
-
   void Rewrite(Expression* new_expression) {
     DCHECK(!is_rewritten());
     DCHECK_NOT_NULL(new_expression);
+    DCHECK(!new_expression->IsRewritableExpression());
     expr_ = new_expression;
     is_rewritten_ = true;
   }
@@ -2524,10 +2515,12 @@
   static int num_ids() { return parent_num_ids(); }
 
  protected:
-  RewritableAssignmentExpression(Zone* zone, Expression* expression)
+  RewritableExpression(Zone* zone, Expression* expression)
       : Expression(zone, expression->position()),
         is_rewritten_(false),
-        expr_(expression) {}
+        expr_(expression) {
+    DCHECK(!expression->IsRewritableExpression());
+  }
 
  private:
   int local_id(int n) const { return base_id() + parent_num_ids() + n; }
@@ -2555,26 +2548,6 @@
   void set_generator_object(Expression* e) { generator_object_ = e; }
   void set_expression(Expression* e) { expression_ = e; }
 
-  // Type feedback information.
-  bool HasFeedbackSlots() const { return yield_kind() == kDelegating; }
-  void AssignFeedbackVectorSlots(Isolate* isolate, FeedbackVectorSpec* spec,
-                                 FeedbackVectorSlotCache* cache) override {
-    if (HasFeedbackSlots()) {
-      yield_first_feedback_slot_ = spec->AddKeyedLoadICSlot();
-      keyed_load_feedback_slot_ = spec->AddLoadICSlot();
-      done_feedback_slot_ = spec->AddLoadICSlot();
-    }
-  }
-
-  FeedbackVectorSlot KeyedLoadFeedbackSlot() {
-    DCHECK(!HasFeedbackSlots() || !yield_first_feedback_slot_.IsInvalid());
-    return yield_first_feedback_slot_;
-  }
-
-  FeedbackVectorSlot DoneFeedbackSlot() { return keyed_load_feedback_slot_; }
-
-  FeedbackVectorSlot ValueFeedbackSlot() { return done_feedback_slot_; }
-
  protected:
   Yield(Zone* zone, Expression* generator_object, Expression* expression,
         Kind yield_kind, int pos)
@@ -2587,9 +2560,6 @@
   Expression* generator_object_;
   Expression* expression_;
   Kind yield_kind_;
-  FeedbackVectorSlot yield_first_feedback_slot_;
-  FeedbackVectorSlot keyed_load_feedback_slot_;
-  FeedbackVectorSlot done_feedback_slot_;
 };
 
 
@@ -2615,15 +2585,13 @@
     kAnonymousExpression,
     kNamedExpression,
     kDeclaration,
-    kGlobalOrEval
+    kAccessorOrMethod
   };
 
   enum ParameterFlag { kNoDuplicateParameters, kHasDuplicateParameters };
 
   enum EagerCompileHint { kShouldEagerCompile, kShouldLazyCompile };
 
-  enum ArityRestriction { kNormalArity, kGetterArity, kSetterArity };
-
   DECLARE_NODE_TYPE(FunctionLiteral)
 
   Handle<String> name() const { return raw_name_->string(); }
@@ -2636,8 +2604,13 @@
   int start_position() const;
   int end_position() const;
   int SourceSize() const { return end_position() - start_position(); }
-  bool is_expression() const { return IsExpression::decode(bitfield_); }
-  bool is_anonymous() const { return IsAnonymous::decode(bitfield_); }
+  bool is_declaration() const { return IsDeclaration::decode(bitfield_); }
+  bool is_named_expression() const {
+    return IsNamedExpression::decode(bitfield_);
+  }
+  bool is_anonymous_expression() const {
+    return IsAnonymousExpression::decode(bitfield_);
+  }
   LanguageMode language_mode() const;
 
   static bool NeedsHomeObject(Expression* expr);
@@ -2729,6 +2702,10 @@
     dont_optimize_reason_ = reason;
   }
 
+  bool IsAnonymousFunctionDefinition() const final {
+    return is_anonymous_expression();
+  }
+
  protected:
   FunctionLiteral(Zone* zone, const AstString* name,
                   AstValueFactory* ast_value_factory, Scope* scope,
@@ -2737,7 +2714,7 @@
                   FunctionType function_type,
                   ParameterFlag has_duplicate_parameters,
                   EagerCompileHint eager_compile_hint, FunctionKind kind,
-                  int position)
+                  int position, bool is_function)
       : Expression(zone, position),
         raw_name_(name),
         scope_(scope),
@@ -2750,26 +2727,28 @@
         parameter_count_(parameter_count),
         function_token_position_(RelocInfo::kNoPosition) {
     bitfield_ =
-        IsExpression::encode(function_type != kDeclaration) |
-        IsAnonymous::encode(function_type == kAnonymousExpression) |
+        IsDeclaration::encode(function_type == kDeclaration) |
+        IsNamedExpression::encode(function_type == kNamedExpression) |
+        IsAnonymousExpression::encode(function_type == kAnonymousExpression) |
         Pretenure::encode(false) |
         HasDuplicateParameters::encode(has_duplicate_parameters ==
                                        kHasDuplicateParameters) |
-        IsFunction::encode(function_type != kGlobalOrEval) |
+        IsFunction::encode(is_function) |
         ShouldEagerCompile::encode(eager_compile_hint == kShouldEagerCompile) |
         FunctionKindBits::encode(kind) | ShouldBeUsedOnceHint::encode(false);
     DCHECK(IsValidFunctionKind(kind));
   }
 
  private:
-  class IsExpression : public BitField16<bool, 0, 1> {};
-  class IsAnonymous : public BitField16<bool, 1, 1> {};
-  class Pretenure : public BitField16<bool, 2, 1> {};
-  class HasDuplicateParameters : public BitField16<bool, 3, 1> {};
-  class IsFunction : public BitField16<bool, 4, 1> {};
-  class ShouldEagerCompile : public BitField16<bool, 5, 1> {};
-  class FunctionKindBits : public BitField16<FunctionKind, 6, 8> {};
-  class ShouldBeUsedOnceHint : public BitField16<bool, 15, 1> {};
+  class IsDeclaration : public BitField16<bool, 0, 1> {};
+  class IsNamedExpression : public BitField16<bool, 1, 1> {};
+  class IsAnonymousExpression : public BitField16<bool, 2, 1> {};
+  class Pretenure : public BitField16<bool, 3, 1> {};
+  class HasDuplicateParameters : public BitField16<bool, 4, 1> {};
+  class IsFunction : public BitField16<bool, 5, 1> {};
+  class ShouldEagerCompile : public BitField16<bool, 6, 1> {};
+  class ShouldBeUsedOnceHint : public BitField16<bool, 7, 1> {};
+  class FunctionKindBits : public BitField16<FunctionKind, 8, 8> {};
 
   // Start with 16-bit field, which should get packed together
   // with Expression's trailing 16-bit field.
@@ -2796,13 +2775,6 @@
 
   DECLARE_NODE_TYPE(ClassLiteral)
 
-  Handle<String> name() const { return raw_name_->string(); }
-  const AstRawString* raw_name() const { return raw_name_; }
-  void set_raw_name(const AstRawString* name) {
-    DCHECK_NULL(raw_name_);
-    raw_name_ = name;
-  }
-
   Scope* scope() const { return scope_; }
   VariableProxy* class_variable_proxy() const { return class_variable_proxy_; }
   Expression* extends() const { return extends_; }
@@ -2817,13 +2789,14 @@
   BailoutId DeclsId() const { return BailoutId(local_id(1)); }
   BailoutId ExitId() { return BailoutId(local_id(2)); }
   BailoutId CreateLiteralId() const { return BailoutId(local_id(3)); }
+  BailoutId PrototypeId() { return BailoutId(local_id(4)); }
 
   // Return an AST id for a property that is used in simulate instructions.
-  BailoutId GetIdForProperty(int i) { return BailoutId(local_id(i + 4)); }
+  BailoutId GetIdForProperty(int i) { return BailoutId(local_id(i + 5)); }
 
   // Unlike other AST nodes, this number of bailout IDs allocated for an
   // ClassLiteral can vary, so num_ids() is not a static method.
-  int num_ids() const { return parent_num_ids() + 4 + properties()->length(); }
+  int num_ids() const { return parent_num_ids() + 5 + properties()->length(); }
 
   // Object literals need one feedback slot for each non-trivial value, as well
   // as some slots for home objects.
@@ -2835,15 +2808,19 @@
            class_variable_proxy()->var()->IsUnallocated();
   }
 
-  FeedbackVectorSlot ProxySlot() const { return slot_; }
+  FeedbackVectorSlot PrototypeSlot() const { return prototype_slot_; }
+  FeedbackVectorSlot ProxySlot() const { return proxy_slot_; }
+
+  bool IsAnonymousFunctionDefinition() const final {
+    return constructor()->raw_name()->length() == 0;
+  }
 
  protected:
-  ClassLiteral(Zone* zone, const AstRawString* name, Scope* scope,
-               VariableProxy* class_variable_proxy, Expression* extends,
-               FunctionLiteral* constructor, ZoneList<Property*>* properties,
-               int start_position, int end_position)
+  ClassLiteral(Zone* zone, Scope* scope, VariableProxy* class_variable_proxy,
+               Expression* extends, FunctionLiteral* constructor,
+               ZoneList<Property*>* properties, int start_position,
+               int end_position)
       : Expression(zone, start_position),
-        raw_name_(name),
         scope_(scope),
         class_variable_proxy_(class_variable_proxy),
         extends_(extends),
@@ -2856,14 +2833,14 @@
  private:
   int local_id(int n) const { return base_id() + parent_num_ids() + n; }
 
-  const AstRawString* raw_name_;
   Scope* scope_;
   VariableProxy* class_variable_proxy_;
   Expression* extends_;
   FunctionLiteral* constructor_;
   ZoneList<Property*>* properties_;
   int end_position_;
-  FeedbackVectorSlot slot_;
+  FeedbackVectorSlot prototype_slot_;
+  FeedbackVectorSlot proxy_slot_;
 };
 
 
@@ -3095,12 +3072,11 @@
 
   AstValueFactory* ast_value_factory() const { return ast_value_factory_; }
 
-  VariableDeclaration* NewVariableDeclaration(
-      VariableProxy* proxy, VariableMode mode, Scope* scope, int pos,
-      bool is_class_declaration = false, int declaration_group_start = -1) {
+  VariableDeclaration* NewVariableDeclaration(VariableProxy* proxy,
+                                              VariableMode mode, Scope* scope,
+                                              int pos) {
     return new (parser_zone_)
-        VariableDeclaration(parser_zone_, proxy, mode, scope, pos,
-                            is_class_declaration, declaration_group_start);
+        VariableDeclaration(parser_zone_, proxy, mode, scope, pos);
   }
 
   FunctionDeclaration* NewFunctionDeclaration(VariableProxy* proxy,
@@ -3389,8 +3365,8 @@
         CompareOperation(local_zone_, op, left, right, pos);
   }
 
-  Spread* NewSpread(Expression* expression, int pos) {
-    return new (local_zone_) Spread(local_zone_, expression, pos);
+  Spread* NewSpread(Expression* expression, int pos, int expr_pos) {
+    return new (local_zone_) Spread(local_zone_, expression, pos, expr_pos);
   }
 
   Conditional* NewConditional(Expression* condition,
@@ -3401,12 +3377,9 @@
         local_zone_, condition, then_expression, else_expression, position);
   }
 
-  RewritableAssignmentExpression* NewRewritableAssignmentExpression(
-      Expression* expression) {
+  RewritableExpression* NewRewritableExpression(Expression* expression) {
     DCHECK_NOT_NULL(expression);
-    DCHECK(expression->IsAssignment());
-    return new (local_zone_)
-        RewritableAssignmentExpression(local_zone_, expression);
+    return new (local_zone_) RewritableExpression(local_zone_, expression);
   }
 
   Assignment* NewAssignment(Token::Value op,
@@ -3449,16 +3422,31 @@
         parser_zone_, name, ast_value_factory_, scope, body,
         materialized_literal_count, expected_property_count, parameter_count,
         function_type, has_duplicate_parameters, eager_compile_hint, kind,
-        position);
+        position, true);
   }
 
-  ClassLiteral* NewClassLiteral(const AstRawString* name, Scope* scope,
-                                VariableProxy* proxy, Expression* extends,
+  // Creates a FunctionLiteral representing a top-level script, the
+  // result of an eval (top-level or otherwise), or the result of calling
+  // the Function constructor.
+  FunctionLiteral* NewScriptOrEvalFunctionLiteral(
+      Scope* scope, ZoneList<Statement*>* body, int materialized_literal_count,
+      int expected_property_count) {
+    return new (parser_zone_) FunctionLiteral(
+        parser_zone_, ast_value_factory_->empty_string(), ast_value_factory_,
+        scope, body, materialized_literal_count, expected_property_count, 0,
+        FunctionLiteral::kAnonymousExpression,
+        FunctionLiteral::kNoDuplicateParameters,
+        FunctionLiteral::kShouldLazyCompile, FunctionKind::kNormalFunction, 0,
+        false);
+  }
+
+  ClassLiteral* NewClassLiteral(Scope* scope, VariableProxy* proxy,
+                                Expression* extends,
                                 FunctionLiteral* constructor,
                                 ZoneList<ObjectLiteral::Property*>* properties,
                                 int start_position, int end_position) {
     return new (parser_zone_)
-        ClassLiteral(parser_zone_, name, scope, proxy, extends, constructor,
+        ClassLiteral(parser_zone_, scope, proxy, extends, constructor,
                      properties, start_position, end_position);
   }
 
@@ -3529,6 +3517,46 @@
 };
 
 
+// Type testing & conversion functions overridden by concrete subclasses.
+// Inline functions for AstNode.
+
+#define DECLARE_NODE_FUNCTIONS(type)                                          \
+  bool AstNode::Is##type() const {                                            \
+    NodeType mine = node_type();                                              \
+    if (mine == AstNode::kRewritableExpression &&                             \
+        AstNode::k##type != AstNode::kRewritableExpression)                   \
+      mine = reinterpret_cast<const RewritableExpression*>(this)              \
+                 ->expression()                                               \
+                 ->node_type();                                               \
+    return mine == AstNode::k##type;                                          \
+  }                                                                           \
+  type* AstNode::As##type() {                                                 \
+    NodeType mine = node_type();                                              \
+    AstNode* result = this;                                                   \
+    if (mine == AstNode::kRewritableExpression &&                             \
+        AstNode::k##type != AstNode::kRewritableExpression) {                 \
+      result =                                                                \
+          reinterpret_cast<const RewritableExpression*>(this)->expression();  \
+      mine = result->node_type();                                             \
+    }                                                                         \
+    return mine == AstNode::k##type ? reinterpret_cast<type*>(result) : NULL; \
+  }                                                                           \
+  const type* AstNode::As##type() const {                                     \
+    NodeType mine = node_type();                                              \
+    const AstNode* result = this;                                             \
+    if (mine == AstNode::kRewritableExpression &&                             \
+        AstNode::k##type != AstNode::kRewritableExpression) {                 \
+      result =                                                                \
+          reinterpret_cast<const RewritableExpression*>(this)->expression();  \
+      mine = result->node_type();                                             \
+    }                                                                         \
+    return mine == AstNode::k##type ? reinterpret_cast<const type*>(result)   \
+                                    : NULL;                                   \
+  }
+AST_NODE_LIST(DECLARE_NODE_FUNCTIONS)
+#undef DECLARE_NODE_FUNCTIONS
+
+
 }  // namespace internal
 }  // namespace v8