[swift-dev] ExistentialMetatypeType assertion failure on Linux

[Luke Howard]

> I think those are all pretty reasonable. The pipeline for changes is bi-directional; however it will have to get reviewed by the component owner and undergo our process to change API behavior internally. I am fairly certain that this is an edge case that hasn’t even been thought of and I would think that the rest of the Foundation team will be very apt to nail this down so we don’t have to worry about backwards compatibility problems that using the mangled name might incur in the future.

If we can get _typeByName() into stdlib (taking an unmangled qualified name), then we could do mangling for nested type names in Foundation and get Darwin archive compatibility that way. It still breaks if the name mangling algorithm changes, but that may be a problem on Darwin too.

— Luke