diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 1b1546fe65..40a5e5f2d1 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -174,7 +174,7 @@ module ActiveRecord
           end
           
           if source_reflection.options[:polymorphic]
-            raise HasManyThroughAssociationPolymorphicError.new(class_name, @reflection, source_reflection)
+            raise HasManyThroughAssociationPolymorphicError.new(class_name, self, source_reflection)
           end
         end
       end