28 Feb
2006
28 Feb
'06
2:23 p.m.
On 2/28/06, Claus Reinke
I'm not sure what you're talking about? both hugs and ghc clearly specify that the more specific instance declaration is chosen when overlapping instance declarations are permitted.
I have trouble with this "more specific" term. It's not well-defined,
i.e. not a total order on possible instance declarations.
The point I was trying to make was that in the case where a
precondition (in this case, Fail a) does not apply, what stops the
resolution algorithm falling back on the other instance declaration?
--
Taral