Malcolm Wallace (malcolm-nhc@cs.york.ac.uk)
Mon, 20 Nov 2000 19:00:30 +0000
Thomas, | > No default for Prelude.Functor at 4:1.(165,[(15,167)]) Here's another workaround for your 3rd bug, and it's a rather obvious one. Try giving a default declaration for your class! For instance, module TypeSigBug where data T a = T class C a instance C T default T f :: C m => m () f = g g :: C m => m () g = f seems to work. This is not legal Haskell'98, because a default declaration should only apply to Num instances. However, provided you do not use any unresolved overloading of numeric types in the same module, nhc98 will accept and use a default decl quite happily for any other class. Regards, Malcolm