Hi

I cannot quickly find on http://www.haskell.org/haskellwiki/Yhc what YHC supports.

From the (just modified) FAQ: http://www.haskell.org/haskellwiki/Yhc/FAQ#Language_Support

Q) What extensions does it support? A) Very few. Existentials and pattern guards are supported. Rank-2 types, multiparameter type classes and most other extensions are not. Thanks Neil