On Tue, Feb 18, 2014 at 3:11 PM, Doug McIlroy
What potential evil motivates the prohibition of repeated type parameters in an instance declaration? (Restriction removed by FlexibleInstances)
Isn't that just related to constraints not being part of instance selection? (Assuming that `instance SomeClass a a` is interpreted as `instance (a ~ b) => SomeClass a b`, since I don't quite see how it would work otherwise given how instances work; the constraint is not necessarily obvious from looking at it. Also note that standard Haskell can't therefore describe this instance properly.) -- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net