Make monorepos awesome when using Nix flakes.
haskell-flake is a flake-parts module for Haskell development. It is used in haskell-template and in several Haskell projects.
You cannot use nix flake check (unless your systems list is singular) due to IFD. You can work around this by using the check-flake flake-parts module; make the following changes to your flake.nix:
nix flake check