Import errors with flat files structure and multiple cabal modules

[KristianBalaj]

Not sure if this is specifically the plugins issue or just a problem with cabal.

I have the following super simple directory structure:

-src
--Main.hs
--Lib.hs
--Test.hs

and module in my cabal file look like this:

library mylib
    exposed-modules:  Lib
    build-depends: base ^>=4.14.3.0
    hs-source-dirs: src
    default-language: Haskell2010

executable myexe
    main-is: Main.hs
    build-depends:    
        base ^>=4.14.3.0, 
        mylib
    hs-source-dirs:   src
    default-language: Haskell2010

test-suite mytest
    type: exitcode-stdio-1.0
    main-is: Test.hs
    build-depends:
        base ^>=4.14.3.0, 
        mylib,
        hspec,
        tasty,
        tasty-hspec
    hs-source-dirs:   src
    default-language: Haskell2010

When having the following imports in the Test.hs file:

import Test.Hspec
import Test.Tasty
import Test.Tasty.Hspec

The VSCode plugin shows me on these lines the following error:

Could not load module ‘Test.Tasty.Hspec’
It is a member of the hidden package ‘tasty-hspec-1.2’.
Perhaps you need to add ‘tasty-hspec’ to the build-depends in your .cabal file.

When I move the Test file into a separate directory or subdirectory, the problem goes away, but I would like not to create subdirectories for such super simple use cases.
I would however expect that the error would not show since the file is only in the mytest module.

[fendor]

Hi, thank you for your bug report!

HLS's implicit project discovery is flawed, currently the best work-around is to have a hie.yaml in your workspace root directory:

cradle:
  cabal:

Relevant issue #2342

some documentation about hie.yaml can be found here: https://github.com/haskell/hie-bios

[michaelpj]

Closing as worked around and an instance of a general problem