"Use fewer imports" suggestion when importing multiple fields from the same record

[ChefYeum]

For instance, for the following line of code:
import Test.Hspec.Formatters (Formatter(failedFormatter), Formatter(footerFormatter))

Suggest the following as alternative:
import Test.Hspec.Formatters (Formatter(failedFormatter, footerFormatter))

Does it sound like a reasonable feature to add under "Use fewer imports" suggestion?

[ndmitchell]

Sounds reasonable - PR most welcome!

[batkot]

This issue will soon get 3yo, but if it's still reasonable, I'll give it a shot 😅

[zliu41]

@batkot Yes this is still relevant! HLint has a "Use fewer imports" warning when the same module is imported multiple times, but not in this case.

[Morabbin]

Apologies for the noise; the two most recent commits are the relevant ones, and are included in this PR.

[Morabbin]

I have a better PR for this now, in draft: #1654.

To sort or not to sort?

Note that sorting occurs only when field imports are combined:

import A (Foo(A,B), Bar(C,D), Foo(E), Foo(C,D))
import A (Foo(A,F), Baz(D,A))

yields the following hint:

import A (Foo(A,B,C,D,E,F), Bar(C,D), Baz(D,A))

Foo's field list is sorted. Note though that Baz's is not, nor is the import list as a whole sorted wrt the type, class, or constructor names imported. The former is straightforward (don't change Baz's import), but the latter requires a kind of stable nub.

The question is: do we prefer sorting any of these lists, or preserving the order of the original?

Sorting everything is simpler (groupSortOn FTW), but I have a feeling this is the hlint way?