ghc: panic!: expectJust, called at compiler/main/Packages.hs:433:5 in ghc:Packages

Summary

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 (closed) but this backtrace looks of different origin so I am reporting here now separately.

Steps to reproduce

stack --resolver lts-17 build fbrnch

Expected behavior

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.

Environment

• GHC version used: 8.10.4

Optional:

• Operating System: Fedora 33
• System Architecture: x86_64