Mixins support

[Martoon-00]

In one of the projects, we are trying to use mixins feature to hide the default Prelude module and provide our own. Then I'm trying to build it with ghcide, but my build fails, saying

Ambiguous module name ‘Prelude’:
  it was found in multiple packages:
  base-4.13.0.0 morley-prelude-0.3.0

I reported this issue (https://github.com/haskell/ghcide/issues/890), however it looks like the problem comes from hie-bios.

For instance, when I try it on our Morley repository, commit e9a00b61bb:

• hie-bios check code/morley/src/Util/Text.hs reports the same error as above.
• hie-bios debug code/morley/src/Util/Text.hs mentions -package-id=base-4.13.0.0, but the information about hidden Prelude is not present.

I'm using stack, and hie.yaml provided by gen-hie.

So my guess is that mixins are not yet supported, is that true? If so, are there plans on implementing this feature?

[fendor]

Does cabal repl or stack repl work for your project? We rely on that and if that works, hie-bios should work, too, imo.

[Martoon-00]

Actually no, stack repl also does not work in my case. Can't make cabal work for some other reasons, but I think it shouldn't have any problems with mixins.

Then I suppose I have to wait for commercialhaskell/stack#5077 to be resolved first, will try to reopen this issue then. Thanks for your quick reply!