On Monday, 9 June 2014 at 16:13:50 UTC, monarch_dodra wrote:
On Monday, 9 June 2014 at 15:54:21 UTC, Ivan Kazmenko wrote:
I'd expect a "multiple overrides of same function" error, much
like if I just paste the mixin code by hand. Is that a bug or
working by design? In the latter case, please explain the
reasoning.
AFAIK, the rationale is that *should* a colision happen, the
local symbol shadows the mixed-in symbol. Doing this avoid
breaking your code just because someone added an extra member
in their mixin, which happened to conflict with one of yours.
The idea is that you can workaround the issue by "naming" your
mixin templates. Then, when you want to access members of the
mixin template, you *know* it'll always work, regardless of
what else may have been declared in your class.
That said, for something like virrtual functions, things get a
bit trickier, since your *aren't* supposed to call them
explicitly... I don't know if bug, or just surprising behavior.
Thank you for the explanation!
I've thought since that for classes, a template mixin of such
kind can, and perhaps should, be replaced by inheritance from
abstract classes or interfaces. There's likely no performance
hit since the virtual table is already there anyway.
Still, I consider reporting this case as a maybe-bug to see more
opinions. At least such shadowing is a case for a static code
analysis tool.
Ivan Kazmenko.
