GHC panic when building with stack

[basetunnel]

I tried to install with the instructions, but got the following error using stack 2.9.1:

jacco@betal082367:~/sources/hs-to-coq$ stack clean
jacco@betal082367:~/sources/hs-to-coq$ stack build
ghc: panic! (the 'impossible' happened)
  (GHC version 8.4.3 for x86_64-unknown-linux):
	Prelude.chr: bad argument: 2600468483

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


--  While building simple Setup.hs (scroll up to its section to see the error) using:
      /home/jacco/.ghcup/ghc/8.4.3/bin/ghc -rtsopts -threaded -clear-package-db -global-package-db -hide-all-packages -package base -main-is StackSetupShim.mainOverride -package Cabal-2.2.0.1 /home/jacco/.stack/setup-exe-src/setup-mPHDZzAJ.hs /home/jacco/.stack/setup-exe-src/setup-shim-mPHDZzAJ.hs -o /home/jacco/.stack/setup-exe-cache/x86_64-linux/tmp-Cabal-simple_mPHDZzAJ_2.2.0.1_ghc-8.4.3
    Process exited with code: ExitFailure 1

As a work-around, I tried running cabal build with ghc 8.10.7, which worked fine.