After transitioning to constant function, return the constant function as result of the assignment.

src/objects.cc

 // Copyright 2012 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 2941 matching lines @@
         }
         return self->ConvertDescriptorToField(*name, *value, attributes);
       }
 
       // Is transition to CONSTANT_FUNCTION.
       Object* constant_function = descriptors->GetValue(descriptor);
       // If the same constant function is being added we can simply
       // transition to the target map.
       if (constant_function == *value) {
         self->set_map(transition_map);
-        return this;
+        return constant_function;
       }
       // Otherwise, replace with a map transition to a new map with a FIELD,
       // even if the value is a constant function.
       return self->ConvertDescriptorToFieldAndMapTransition(*name,
                                                             *value,
                                                             attributes);
     }
     case HANDLER:
     case NONEXISTENT:
       UNREACHABLE();
@@ skipping 10299 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal