You can get full pattern match checking via -fwarn-incomplete-patterns. Crashing on bottom is a concession to the fact that crashing is more useful than infinit

You can get full pattern match checking via -fwarn-incomplete-patterns. Crashing on bottom is a concession to the fact that crashing is more useful than infinite loops. The semantics of the program exiting are the same as the semantics of the program infinite looping. So I'd say it's as pure as you can get on a finite state computer.