Implement proper scoping for "this" in arrow functions

src/scopes.h

 // 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.
 
 #ifndef V8_SCOPES_H_
 #define V8_SCOPES_H_
 
 #include "src/ast.h"
 #include "src/zone.h"
 
 namespace v8 {
 namespace internal {
 
 class CompilationInfo;
 
 
 // A hash map to support fast variable declaration and lookup.
 class VariableMap: public ZoneHashMap {
  public:
   explicit VariableMap(Zone* zone);
 
   virtual ~VariableMap();
 
   Variable* Declare(Scope* scope, const AstRawString* name, VariableMode mode,
-                    bool is_valid_lhs, Variable::Kind kind,
-                    InitializationFlag initialization_flag,
+                    Variable::Kind kind, InitializationFlag initialization_flag,
                     MaybeAssignedFlag maybe_assigned_flag = kNotAssigned);
 
   Variable* Lookup(const AstRawString* name);
 
   Zone* zone() const { return zone_; }
 
  private:
   Zone* zone_;
 };
 
@@ skipping 98 matching lines @@
 
   // Declare an implicit global variable in this scope which must be a
   // script scope.  The variable was introduced (possibly from an inner
   // scope) by a reference to an unresolved variable with no intervening
   // with statements or eval calls.
   Variable* DeclareDynamicGlobal(const AstRawString* name);
 
   // Create a new unresolved variable.
   VariableProxy* NewUnresolved(AstNodeFactory* factory,
                                const AstRawString* name,
+                               Variable::Kind variable_kind,
                                int position = RelocInfo::kNoPosition) {
     // Note that we must not share the unresolved variables with
     // the same name because they may be removed selectively via
     // RemoveUnresolved().
     DCHECK(!already_resolved());
-    VariableProxy* proxy = factory->NewVariableProxy(name, false, position);
+    VariableProxy* proxy =
+        factory->NewVariableProxy(name, variable_kind, position);
     unresolved_.Add(proxy, zone_);
     return proxy;
   }
 
   // Remove a unresolved variable. During parsing, an unresolved variable
   // may have been added optimistically, but then only the variable name
   // was used (typically for labels). If the variable was not declared, the
   // addition introduced a new unresolved variable which may end up being
   // allocated globally as a "ghost" variable. RemoveUnresolved removes
   // such a variable again if it was added; otherwise this is a no-op.
@@ skipping 159 matching lines @@
   // ---------------------------------------------------------------------------
   // Accessors.
 
   // The type of this scope.
   ScopeType scope_type() const { return scope_type_; }
 
   // The language mode of this scope.
   LanguageMode language_mode() const { return language_mode_; }
 
   // The variable corresponding to the 'this' value.
-  Variable* receiver() { return receiver_; }
+  Variable* receiver() {
+    DCHECK(has_this_declaration());
+    DCHECK_NOT_NULL(receiver_);
+    return receiver_;
+  }
+
+  bool has_this_declaration() const {
+    return !is_arrow_scope() && is_declaration_scope();
+  }
 
   // The variable corresponding to the 'new.target' value.
   Variable* new_target_var() { return new_target_; }
 
   // The variable holding the function literal for named function
   // literals, or NULL.  Only valid for function scopes.
   VariableDeclaration* function() const {
     DCHECK(is_function_scope());
     return function_;
   }
@@ skipping 314 matching lines @@
   bool HasArgumentsParameter(Isolate* isolate);
 
   // Variable allocation.
   void AllocateStackSlot(Variable* var);
   void AllocateHeapSlot(Variable* var);
   void AllocateParameterLocals(Isolate* isolate);
   void AllocateNonParameterLocal(Isolate* isolate, Variable* var);
   void AllocateNonParameterLocals(Isolate* isolate);
   void AllocateVariablesRecursively(Isolate* isolate);
   void AllocateModulesRecursively(Scope* host_scope);
+  void AllocateParameter(Variable* var, int index);
+  void AllocateReceiver();
 
   // Resolve and fill in the allocation information for all variables
   // in this scopes. Must be called *after* all scopes have been
   // processed (parsed) to ensure that unresolved variables can be
   // resolved properly.
   //
   // In the case of code compiled and run using 'eval', the context
   // parameter is the context in which eval was called.  In all other
   // cases the context parameter is an empty handle.
   MUST_USE_RESULT
@@ skipping 19 matching lines @@
                    Scope* outer_scope,
                    Handle<ScopeInfo> scope_info);
 
   AstValueFactory* ast_value_factory_;
   Zone* zone_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCOPES_H_