1 files changed, 2 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/associations/builder/collection_association.rb b/activerecord/lib/active_record/associations/builder/collection_association.rb
index e53665ce82..e78d25441b 100644
--- a/activerecord/lib/active_record/associations/builder/collection_association.rb
+++ b/activerecord/lib/active_record/associations/builder/collection_association.rb
@@ -22,9 +22,9 @@ module ActiveRecord::Associations::Builder # :nodoc:
 
     def self.define_extensions(model, name, &block)
       if block_given?
-        extension_module_name = "#{model.name.demodulize}#{name.to_s.camelize}AssociationExtension"
+        extension_module_name = "#{name.to_s.camelize}AssociationExtension"
         extension = Module.new(&block)
-        model.module_parent.const_set(extension_module_name, extension)
+        model.const_set(extension_module_name, extension)
       end
     end