Thank you for all the replies and especially pointing to this ticket.

I think, the discussion on this ticket is actually misleading and there is a simple solution, which I added as a comment.

Manuel

Thomas Miedema <thomasmiedema@gmail.com>:


It would be great if someone could create a Trac ticket

Existing ticket: https://ghc.haskell.org/trac/ghc/ticket/11529 ("Show instance of Char should print literals for non-ascii printable charcters")