HLS & GHC versions - Haskell

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Giovanni Santiago

I'm having what is probably a very simple problem. I created a very basic project with cabal init, and opened the folder with VSCode.

When HLS tries to load, it spits out the error ERROR Error: HLS does not support GHC 8.10.7 yet., which is _fine_.

The problem is that nowhere have I specified GHC 8.10.7, so it is determining this version automatically. But if HLS doesn't support it, I obviously want to use a different version of GHC. How would I go about doing this? Every bit of info I find on this error simply says that some versions of GHC are unsupported, and a list of supported versions. However, I have no clue whatsoever of how to _ask_ HLS to use a specific version.


Do you have some system-wide GHC installation? Or do you use ghcup?

Vance Palacio

I've ran into that error before. I don't remember exactly what I did to remedy it, but I think maybe it had something to do with which version of HLS you're using.
The VsCode HLS extension worked a little better for me when it automatically installed HLS, but now it defeats to ghcup to handle it (or you supplying a path to your own HLS binary). You might try installing ghcup (if you're not already using it) and try installing/selecting a different version of HLS to try with it