Support PackageImports in hiddenPackageSuggestion

[jian-lin]

Fix: #4479

TODO: Probably I need to add more tests.

CC @VeryMilkyJoe @fendor

Video demo

hls-4479-demo.mp4

More info

Here is the string being matched.

With PackageImports

not found: Could not find module ‘Data.List.Split’
Perhaps you meant
  Data.List.Split (needs flag -package-id split-0.2.5)
  Data.List.Split (needs flag -package-id split-0.2.5)

Without PackageImports

not found: Could not load module ‘Data.List.Split’
It is a member of the hidden package ‘split-0.2.5’.
Perhaps you need to add ‘split’ to the build-depends in your .cabal file.
It is a member of the hidden package ‘split-0.2.5’.
Perhaps you need to add ‘split’ to the build-depends in your .cabal file.

I also notice that the "not found" error remains even after the dependency is added by the code action (with and without PackageImports). That may be a bug of my lsp client (eglot on Emacs) or HLS. Needs further investigation.

[jian-lin]

I think I have addressed all previous comments. Please take another look.

[fendor]

LGTM, thank you for your contribution ❤️

[jian-lin]

Thanks for your review! I had a great experience in my first HLS PR.

[jian-lin]

I also notice that the "not found" error remains even after the dependency is added by the code action (with and without PackageImports). That may be a bug of my lsp client (eglot on Emacs) or HLS. Needs further investigation.

Oh, it is indeed a known HLS bug. With HLS 2.10.0.0 and vscode 2.5.3, I need to manually restart HLS or saving hie.yaml after adding dependencies to .cabal file to let HLS find the newly added dependencies.

In addition, there seems to be a bug in my preferred setting: Emacs with eglot as a LSP client. In that setting, only manual restart works and saving hie.yaml has no effect.

[fendor]

Yes, that sounds correct!

[fendor]

@jian-lin It looks like you need to rebase your PR or merge changes from master into it before we can merge :)

[jian-lin]

@fendor Rebased.

[VeryMilkyJoe]

LGTM, thank you!