Can you elaborate on this? Just the basic proposal without any of the enhancements that have been discussed would be enough to eliminate the need for this awful hack that prevents conformances from being added outside a module. I have needed to use that hack in a few places and would very much like to get rid of it.
The fact is that there are important library design techniques that don’t work if conformances can be added outside the library. I think enabling them is an important goal and reduces complexity for both libraries and users by allowing the library to more clearly state its intent within the language itself.