Performance regression on typechecking type families?

[Simon Peyton Jones]

| I personally have run into exponential compile times with type families.
| Unfortunately I have not
| had the time yet to reduce my test case to something tractable.

Ha!  If you do find the time, I'm sure everyone would be grateful.  Just use the time while waiting for the type checker. If it is truly exponential, you will easily have enough waiting time :-)

Simon