Hi, I'm not sure "I18n namespace lookup" mean but there's some libraries (like GitHub - nofxx/symbolize: Symbolize attribute values in ActiveRecord or Mongoid (nicer enums)) that use nested key in a way that I find perfectly logical, so I wonder if that warning isn't superfluous as there might be a lot of useful ways to leverage the AR locales that are legit and outside Rails control. In the end I'm really not sure deprecation warnings make sense for what is essentially data!
I was thinking about this and should this warning appear only for keys which correspond to an actual attribute?