7 Feb
2012
7 Feb
'12
4:05 a.m.
On Tue, Feb 7, 2012 at 7:23 AM, Mikhail Vorozhtsov
Even better, you can write
type ExistentialWith c e = (Existential e, c ~ ConstraintOf e)
instead of
class (Existential e, c ~ ConstraintOf e) => ExistentialWith c e instance (Existential e, c ~ ConstraintOf e) => ExistentialWith c e
and drop UndecidableInstances.
I actually mentioned this in the preceding point of the [snip]. The problem is that it's not even better because you can't partially apply it.