Proposal for def_method_missing in ActiveSupport

-1

I don’t think this feature would be useful to the majority of Rails developers out there, sorry.

You could always release it as a separate gem and get people to use it that way.

Yes. However, this is something currently implemented in Rails already (e.g., SomeModel#find_by_foo_and_bar_and_baz). Rails itself could benefit from the abstraction being put into ActiveSupport.