How wide or narrow should cabal dependency version constraints be?

Question

I recently uploaded a Haskell project to Hackage, but I was uncertain how narrow or wide I should make my dependency version constraints in the cabal file. Are there any guidelines for this?

Answer 1

There is the Haskell Package Versioning Policy, which gives clear guidance.

But I should add that these are not universally accepted, and cause regular heated debates, especially the upper version bound on dependencies.