rails/rails — comment on commit 0be5adaedf6565630bed04c6c651f3ff8d77c5b8
File: activerecord/lib/active_record/base.rb line 2216
By dmitriy-kiriyenko:

@fxn, what's the point of converting that module to `ActiveSupport::Concern`? There are still no instance methods there, so it's quite logical for the module to be an extension, not inclusion.