Building HEAD devel2 flavour panics in CorePrep
Steps to reproduce
Check out a clean master
at 13d3c613. Boot, configure, and run hadrian/build -o_corePrepBug --flavour=devel2
. This eventually fails while compiling _corePrepBug/stage1/compiler/build/GHC/Parser/Lexer.hs
with the following panic:
ghc: panic! (the 'impossible' happened)
GHC version 9.9.20231014:
cpeBind
Case top-lvl sat_sj8D :: Ord [Char]
[LclId]
sat_sj8D = $fOrdList @Char $fOrdChar
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/GHC/Utils/Panic.hs:186:37 in ghc:GHC.Utils.Panic
pprPanic, called at compiler/GHC/CoreToStg/Prep.hs:652:46 in ghc:GHC.CoreToStg.Prep
CallStack (from HasCallStack):
panic, called at compiler/GHC/Utils/Error.hs:511:29 in ghc:GHC.Utils.Error
Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug
Expected behavior
...successful build...
Environment
- GHC version used:
master
at 13d3c613 - Alex version 3.4.0.0
This probably indicates a bug in the very recently merged !11368 (closed). (cc @sgraf812)