only when eval in Language Server: certain TemplateHaskell module not found

[archywillhe]

So I'm using using some TemplateHaskell packages. Namely Data.Aeson.TypeScript.TH.

The code got compiled and all was good.

So it's working just great.

But if I'm debugging and try to eval in the Haskell Language Server I will get an error of module not found:

--- >>> runInterpreter $ runHint "HsToRedux_item" "2023-08-16_18-06-51"    
-- Left (WontCompile [GhcError {errMsg = "_mixed/HsToRedux_item/2023-08-16_18-06-51.hs:13:1: error:\n    Could not find module \8216Data.Aeson.TypeScript.TH\8217\n    Use -v (or `:set -v` in ghci) to see a list of the files searched for."},GhcError {errMsg = "_mixed/HsToRedux_item/2023-08-16_18-06-51.hs:14:1: error:\n    Could not find module \8216Data.Aeson.Types\8217\n    Use -v (or `:set -v` in ghci) to see a list of the files searched for."}])

(I did setImports ["Prelude", "Language.Haskell.TH", "GHC.Generics", "Data.Aeson", "Data.Aeson.TypeScript.TH","Data.Aeson.Types"] just fine with set [languageExtensions := [TemplateHaskell,ScopedTypeVariables]])

or can probably be a bug somewhere in the HLS?

[archywillhe]

any tips on debugging this or hacking around will be nice! Thanks!

[gelisam]

hint is not finding the package databases in which that library is installed. The README recommends using a ghc environment file in the present working directory, as I have had a good experience with that approach with both running a compiled executable, with ghci, and ghcid. However, I have not tried this approach with HLS, so it is possible that the second approach mentioned in the README, in which the ghc environment file or the package database is explicitly specified via unsafeRunInterpreterWithArgs, works better.

It is also possible that HLS is setting the GHC_PACKAGE_PATH environment variable.

Does that help?