Neil,
As discussed on #haskell, the following code:
---------------- module Foo where foo = do (1 :: Int) ----------------
Compiles fine on Yhc, but doesn't on Hugs and GHC.
So the question is, who is right? Where do the bugs need filing? Does this issue need clarifying for Haskell' ?
Well, the Report (Sec. 3.14) states that, for any expression e, do {e} should be translated to e. So foo = do (1 :: Int} should be translated to foo = (1 :: Int) which seems type correct to me. However, although the Report does not state it explicitly, I think it was the intention of the language designers to always associate a do- block with a particular monad. So, maybe this should be stated (in some form) in the Report for Haskell'. Cheers, Stefan