To add some context to this, the reason why packages which depend on haskell in arch are such a mess is because "the arch way" is to dynamically link everything. This has its advantages (namely security), but is not super compatible with the haskell ecosystem which is designed with static linking in mind.
Like my parent commenter, I recommend just doing everything through stack. stack-static from the AUR [0] is the convenient way to do this (rather than dragging in a few gigs of ghc dependencies for stack only to have stack create its own local ghc installation as well).
[0] https://aur.archlinux.org/packages/stack-static/