This module provides utilities to ensure that you propagate HasCallStack constraints by introducing a class RequireCallStack which can only be discharged using the provideCallStack function.

Let's say you have a custom prelude for your project, and you want better callstack support. You replace the error with a custom variant:

error :: RequireCallStack => String -> a
error = Prelude.error

Now, you will receive a compile-time error at every use site of error in your project. These errors will complain about a missing instance of some weird class that gently suggests to add a RequireCallStack constraint, or use provideCallStack to discharge it. You can add RequireCallStack constraints up the stack, until eventually, you have complete provenance information. Or, if you want to make the work a bit easier, you can use provideCallStack to dismiss the constraint.

foo :: RequireCallStack => Int -> String
foo = error "oh no"

bar :: Int -> String
bar i = provideCallStack $ foo i

Couple this with annotated-exception library for excellent provenance information on all thrown exceptions.