Simon, thanks for the explanation, that makes a bit more sense now.
So the situation is that a relaxation of this rule is possible,
it's just a matter of whether this would ever be any use to anyone,
and indeed worth the extra pain of all those (additional) Overlapping
Instance!, and Ambiguity! e
> While hacking around with MPCs, trying to define a variant of the
> Collection class, mutated to suit my own fiendish ends, I ran into
> this:
>
> Intervals.hs:345:
> Class type variable `e' does not appear in method signature
> union2 :: s -> s -> s
>
> What's the significance o
While hacking around with MPCs, trying to define a variant of the
Collection class, mutated to suit my own fiendish ends, I ran into
this:
Intervals.hs:345:
Class type variable `e' does not appear in method signature
union2 :: s -> s -> s
What's the significance of this restriction?