Make proxies work as prototypes.

src/ic.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1347 matching lines @@
   if (!lookup->IsPropertyOrTransition() || !lookup->IsCacheable()) return false;
 
   // If the property is read-only, we leave the IC in its current
   // state.
   if (lookup->IsReadOnly()) return false;
 
   return true;
 }
 
 
-static bool LookupForWrite(JSReceiver* receiver,
+static bool LookupForWrite(JSObject* receiver,
                            String* name,
                            LookupResult* lookup) {
   receiver->LocalLookup(name, lookup);
   if (!StoreICableLookup(lookup)) {
     return false;
   }
 
-  if (lookup->type() == INTERCEPTOR) {
-    JSObject* object = JSObject::cast(receiver);
-    if (object->GetNamedInterceptor()->setter()->IsUndefined()) {
-      object->LocalLookupRealNamedProperty(name, lookup);
-      return StoreICableLookup(lookup);
-    }
+  if (lookup->type() == INTERCEPTOR &&
+      receiver->GetNamedInterceptor()->setter()->IsUndefined()) {
+    receiver->LocalLookupRealNamedProperty(name, lookup);
+    return StoreICableLookup(lookup);
   }
 
   return true;
 }
 
 
 MaybeObject* StoreIC::Store(State state,
                             StrictModeFlag strict_mode,
                             Handle<Object> object,
                             Handle<String> name,
                             Handle<Object> value) {
-  // If the object is undefined or null it's illegal to try to set any
-  // properties on it; throw a TypeError in that case.
-  if (object->IsUndefined() || object->IsNull()) {
-    return TypeError("non_object_property_store", object, name);
-  }
+  if (!object->IsJSObject()) {
+    // Handle proxies.
+    if (object->IsJSProxy()) {
+      return JSProxy::cast(*object)->
+          SetProperty(*name, *value, NONE, strict_mode);
+    }
 
-  if (!object->IsJSReceiver()) {
+    // If the object is undefined or null it's illegal to try to set any
+    // properties on it; throw a TypeError in that case.
+    if (object->IsUndefined() || object->IsNull()) {
+      return TypeError("non_object_property_store", object, name);
+    }
+
     // The length property of string values is read-only. Throw in strict mode.
     if (strict_mode == kStrictMode && object->IsString() &&
         name->Equals(isolate()->heap()->length_symbol())) {
       return TypeError("strict_read_only_property", object, name);
     }
-    // Ignore stores where the receiver is not a JSObject.
+    // Ignore other stores where the receiver is not a JSObject.
     return *value;
   }
 
-  // Handle proxies.
-  if (object->IsJSProxy()) {
-    return JSReceiver::cast(*object)->
-        SetProperty(*name, *value, NONE, strict_mode);
-  }
-
   Handle<JSObject> receiver = Handle<JSObject>::cast(object);
 
   // Check if the given name is an array index.
   uint32_t index;
   if (name->AsArrayIndex(&index)) {
     HandleScope scope(isolate());
     Handle<Object> result = SetElement(receiver, index, value, strict_mode);
     if (result.is_null()) return Failure::Exception();
     return *value;
   }
@@ skipping 1107 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal