ghc: panic!: expectJust, called at compiler/main/Packages.hs:433:5 in ghc:Packages
ghc-8.10 is crashing when compiling/linking(?) a medium-sized executable for me.
With both ghc-8.10.3 and ghc-8.10.4 on Fedora 33 x86_64:
[41 of 42] Compiling Paths_fbrnch [42 of 42] Compiling Main [Distribution.Fedora.Branch changed] ghc: panic! (the 'impossible' happened) (GHC version 8.10.3: expectJust getPackageDetails CallStack (from HasCallStack): error, called at compiler/utils/Maybes.hs:57:27 in ghc:Maybes expectJust, called at compiler/main/Packages.hs:433:5 in ghc:Packages Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug
I originally mentioned this in #18284 but this backtrace looks of different origin so I am reporting here now separately.
Steps to reproduce
stack --resolver lts-17 build fbrnch
Compile the program without panicking (like 8.8.4 does successfully). Not having to re-run the build to get it to complete.
I don't feel confident with updating Fedora to 8.10 with this issue existing, though admittedly this is not a Fedora ghc build.
- GHC version used: 8.10.4
- Operating System: Fedora 33
- System Architecture: x86_64