ghc: panic! (the 'impossible' happened)
## Summary
GHC asks me to report a bug.
## Steps to reproduce
Trying to install Agda v2.5.1 using the Haskell Tool Stack:
```
git clone git@github.com:agda/agda.git agda-2.5.1
cd agda-2.5.1
git checkout v2.5.1.2.20161216
stack --stack-yaml stack-8.0.1.yaml install
```
## Expected behavior
Assuming that the bug is there, for me it outputs the following message:
```
ghc: panic! (the 'impossible' happened)
(GHC version 8.0.1 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/<username>/.stack/programs/x86_64-linux/ghc-tinfo6-8.0.1/bin/ghc-8.0.1 -rtsopts -threaded -clear-package-db -global-package-db -hide-all-packages -package base -main-is StackSetupShim.mainOverride -package Cabal-1.24.0.0 /home/<username>/.stack/setup-exe-src/setup-mPHDZzAJ.hs /home/<username>/.stack/setup-exe-src/setup-shim-mPHDZzAJ.hs -o /home/<username>/.stack/setup-exe-cache/x86_64-linux-tinfo6/tmp-Cabal-simple_mPHDZzAJ_1.24.0.0_ghc-8.0.1
Process exited with code: ExitFailure 1
```
Ideally it would just install Agda of course.
## Environment
* GHC version used: 8.0.1 I suppose.
Optional:
* Operating System: Ubuntu 21.04 (Kubuntu)
* System Architecture:
issue