fix issue 19729 - Constructor overloads coming from mixin are not resolved

[ghost]

The test b17259.d was created to check that an ICE was fixed but then this became a reject-valid.
Make it working for good this time.

[dlang-bot]

Thanks for your pull request, @NilsLankila!

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	19729	normal	Constructor overloads coming from mixin are not resolved

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#11652"

[Geod24]

This needs a bit more test.

1. Add a test with named mixin
2. How does it work in case of conflict ?
3. How does it work if there's an exact match mixed in and a conversion match at the top level

[ghost]

I can answer, as overload sets are tried at the end:

How does it work in case of conflict ?

mixin looses, top level decl wins

How does it work if there's an exact match mixed in and a conversion match at the top level

mixin looses, top level decl wins

But I'll push tests. The idea, as specified in the official doc is that one can name a mixin when there are conflicts. For constructor this is not possible to disambiguate so top level wins.

[ghost]

ping @Geod24, I have pushed the tests you required four days ago, requested a second review but you still block this bugfix.

[Geod24]

ping @Geod24, I have pushed the tests you required four days ago, requested a second review but you still block this bugfix.

Not on purpose, I promise, because I'm looking forward to this bug fix too :)
For reference, anyone is free to discard an (addressed) review if the reviewer is busy.

I added a last test case, otherwise LGTM.