-ddump-if-trace

[Simon Peyton-Jones]

| Well, that just means we don't have any tests for the parts of the
| library that I'm working on (:
| Oh, and last nights build had 120 unexpected test failures. Should I
| be worried or is it OK?

A bunch of these are typechecker failures replicated 5 times (for the
different ways); and they are still failing because the story for scoped
type variables is still in flux.  

S