HLS deletes shebang line

[Vic-M]

HLS deletes the shebang line in single file scripts when accepting a suggestion.

Your environment

Which OS do you use? Windows WSL2 running CentOS Stream 9

Which version of GHC do you use and how did you install it? GHC 9.4.8 from ghcup

Which LSP client (editor/plugin) do you use? vscode haskell

Which version of HLS do you use and how did you install it? HLS 2.7.0.0 from ghcup

Steps to reproduce

Use the following the code:

#!/usr/bin/env cabal

{- cabal:
default-language: GHC2021

build-depends:
    base ^>=4.17.0.0,
-}

main :: IO ()
main = print $ fmap (\x -> x + 1) [1,2,3]

Accept the suggestion.

Expected behaviour

#!/usr/bin/env cabal

default-language: GHC2021

{- cabal:
default-language: GHC2021

build-depends:
    base ^>=4.17.0.0,
-}

main :: IO ()
main = print $ fmap (+ 1) [1,2,3]

Actual behaviour

{- cabal:
default-language: GHC2021

build-depends:
    base ^>=4.17.0.0,
-}

main :: IO ()
main = print $ fmap (+ 1) [1,2,3]

[fendor]

Hi, thank you for your bug report! This bug was previously reported and fixed in #2724, but it clearly came back :(

This bug is likely in apply-refact and consequentially in ghc-exactprint. Can we verify this happens in hlint on the cli, without HLS?

[jhrcek]

I confirm I can reproduce the issue with the latest versions of apply-refact + latest hlint. I saw ghc-exactprint 1.6.1.3 being used when installing apply-refact (as I installed hlint + apply-refact with ghc 9.4.8).

Indeed the shebang is removed as you can see in the steps below.

$ refactor --version
v0.14.0.0
$ hlint --version
HLint v3.8, (C) Neil Mitchell 2006-2024
$ cat Script.hs 
#!/usr/bin/env cabal

{- cabal:
default-language: GHC2021

build-depends:
    base ^>=4.17.0.0,
-}

main :: IO ()
main = print $ fmap (\x -> x + 1) [1,2,3]

$ hlint Script.hs 
Script.hs:11:21-33: Suggestion: Avoid lambda using `infix`
Found:
  (\ x -> x + 1)
Perhaps:
  (+ 1)

1 hint
$ hlint Script.hs --refactor --refactor-options="--inplace"
$ cat Script.hs 


{- cabal:
default-language: GHC2021

build-depends:
    base ^>=4.17.0.0,
-}

main :: IO ()
main = print $ fmap (+ 1) [1,2,3]

[michaelpj]

This is an upstream bug, it sounds like?

[jhrcek]

Found this https://github.com/mpickering/apply-refact/issues/140 so even though the issue might have been fixed in ghc-exactprint, it seems to be still present in apply-refact..?