[swift-evolution] Eliminate inconsistencies among primary collection types

[Dave Abrahams]

on Fri Apr 29 2016, "Wolfgang H. via swift-evolution" <swift-evolution at swift.org> wrote:

> A. When trying to declare nested collection types an inconsistency
>    is unveiled:

AFAICT this is all due to the lack of a compiler feature called
“constrained conformances,” which we'd like to implement but don't have
yet.

-- 
Dave