22 Feb
2001
22 Feb
'01
1:31 a.m.
George Russell writes: | Excuse me, but is it a bug or a feature that Hugs (98-Feb2001), with | the -98 option, rejects: | | data G b = forall a . H a b => G a b | | class H a b where | | with "Variable "b" in constraint is not locally bound"? What do you intend for the type of G? G :: H a b => a -> b -> G b ...but where does the "forall a" go? Apart from the lack of a functional dependency in the H decl, this looks like a recent thread on the main Haskell list, subject "Fundeps and quantified constructors". The original question: http://www.mail-archive.com/haskell@haskell.org/msg07982.html The realisation that GHC permitted it: http://www.mail-archive.com/haskell@haskell.org/msg08036.html Regards, Tom