hspec usually outputs the source location of failing tests, but this doesn't work for tests that use combinators from hspec-megaparsec. Instead it just prints Test/Hspec/Megaparsec.hs as location.

To make this work, hspec-megaparsec would just need to add a HasCallStack constraint to every combinator, which is quite trivial to do if you're willing to depend on hspec-expectations >= 0.8 since it exports HasCallStack. Otherwise, you could steal their code