Hello!

You can turn off the pattern match checker, is that an option?

How?

Can you post your code which shows the poor behaviour. It could be good to profile that part of GHC to see if there are any easy gains but it is known to be slow.

I attached a minimal example in the original e-mail. The code that triggers the really bad case is not much bigger. It is divided in many more modules, though. Cheers, Victor