I think that [`attribute_missing` still exists](https://github.com/rails/rails/blob/master/activemodel/lib/active_model/attribute_methods.rb#L448), so what's being removed is actually `usage of method_missing to dispatch attributes that are columns`, [as per the original commit description](https://github.com/rails/rails/commit/1a421ceccb25b15c87e97567fff573c941aa3ab3). Wdyt?