[Issue 17859] importing the same`mixin template` results in `isn't a template` error instead of the expected `conflicts with alias` error

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=17859

Iain Buclaw <ibuclaw at gdcproject.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P1                          |P3

--