I’ve been happily using Haskell for a couple of years through Nix like so:

(pkgs.haskell.packages.ghc910.override {overrides = ...;}).ghcWithPackages(p: [...])

However recently one of my haskell apps started crashing with an exception from time to time. I am hunting for a way to have a call-stack printed for these exceptions. Since I don’t control third party libraries I cannot add HasCallstack to them to be able to debug that way so I have been trying to compile with -prof for the last couple of days with no success.

Does anyone have a working example of how to get this working?