Carter Schonwald
Ccing ghc devs since that’s a better forum perhaps Crazy theory:
this is a regression due the the partial changes to pattern matching coverage checking in 8.10 that finished / landed in ghc 9
Why: Desugaring is when pattern/ case statement translation happens I think? And the only obvious “big thing” is that you have some huge , albeit sane for a compiler, pattern matching
I’d first check if the new ghc 9 release doesn’t have that regression in build time that you experienced. And if it does file a ticket.
I may be totally wrong, but that seems like a decent likelihood !
You may be right! Another module that regressed is also mainly characterised by large-but-not-insane case expressions: https://github.com/diku-dk/futhark/blob/d0839412bdd11884d75a1494dd5de5191833... I'll try to split these modules up a little bit (I should have done so a while ago anyway) and maybe that will make the picture even clearer. -- \ Troels /\ Henriksen