25 Mar
2019
25 Mar
'19
1:45 a.m.
On Mon, Mar 25, 2019 at 6:24 PM Anthony Clayden < anthony_clayden@clear.net.nz> wrote:
...
Errk. pasted the wrong example. The code that works is class F a b | a -> b instance F Int Bool class D a where { op :: (F a b) => a -> b } instance (TypeCast Bool b') => D Int where { op _ = typeCast True } That dangling `b'` in the constraint is weird. Anyhow: compiles in Hugs, doesn't in GHC. Unless someone here can persuade it? AntC