On Tue, 12 May 2020 at 17:30, Henning Thielemann <lemming@henning-thielemann.de> wrote:

From your list of examples I deduce that the proposal is about programming
errors. But we have HasCallStack for that one. How does the proposal
improve or alter the HasCallStack solution? And how does it relate to the
IO exception system with hierarchical exceptions and SomeException and so
on?

As a parallel item, maybe it would be good if incomplete patterns could have a HasCallStack constraint so the current "Non-exaustive patterns in function foo" message could be extended with a helpful backtrace? If a programmer doesn't want this, then they could use complete matches?