panic with ghc 9.0.2

[bergmark]

[ 7 of 18] Compiling Data.Primitive.Unlifted.MVar.Primops ( ... )
ghc-9.0.2: panic! (the 'impossible' happened)
  (GHC version 9.0.2:
	findSlot
  Can't find slot
  [PtrUnliftedSlot]
  [PtrLiftedSlot]
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler/GHC/Utils/Outputable.hs:1230:37 in ghc:GHC.Utils.Outputable
        pprPanic, called at compiler/GHC/Types/RepType.hs:217:9 in ghc:GHC.Types.RepType

Please report this as a GHC bug:  https://www.haskell.org/ghc/reportabug

[jneira]

9.0.2 support for haskell-language-server is blocked on this so we hope ther could be a fix for 9.0
Issue in the ghc repo: https://gitlab.haskell.org/ghc/ghc/-/issues/20908

any chance of getting a fix in the library itself @chessai? thanks in advance!

[chessai]

How would you propose this is fixed? If the MVar module doesn't get compiled, does this happen with other modules? This unsafeCoerce# trick is used pretty liberally throughout the library. What is a minimal fix that would allow hls to proceed? This library will be obsolete soon so I'm mostly worried about making sure existing users can experience less disruption

[jneira]

This library will be obsolete soon so I'm mostly worried about making sure existing users can experience less disruption

thanks for the quick response, didn't know the library was about to be deprecated, where could we check more info about that? does it depend on a new ghc version? is there a known replacement?

in that case it seems the solution would be using a previous version of the library downstream as suggesteddone in nikita-volkov/primitive-extras#6