Try haskell-ide-engine on GHC

instr.md

These are instructions about how to use the experimental support for haskell-ide-engine on GHC.

Note that this will only work whilst editing the main compiler currently, it won't work with subcomponents or hadrian. That's future work.

1. Build this branch using cabal new-build - https://github.com/mpickering/haskell-ide-engine/tree/hie-bios
2. Install the "Haskell Language Server" extension in vscode
3. Set the "Hie Executable Path" to the executable you just built
4. Disable "Diagnostics on Change" - It's too slow to work on GHC.
5. Create a hie.yaml file in the root directory with the following contents:

cradle: {bios: {program: "hie-bios"}}

6. Create an executable file in the root directory called hie-bios

#! /usr/bin/env bash
echo $(TERM=dumb CABFLAGS=-v0 ./hadrian/build.cabal.sh tool-args -q --build-root=_ghci --flavour=ghc-in-ghci) -ighc ghc/Main.hs

7. Execute the hie-bios file in your terminal - it should take 1-2 minutes before printing out some options. This is a testing step to see everything is set up properly.

8. Open the GHC folder in vscode and open a file such as compiler/utils/FV.hs. After a short period editor features should work. Try hovering, going to definition, finding references and so on.