I thought that might be the case. Thanks for that! Cheers, Reiner
On 17/01/2012, at 1:15 AM, Simon Peyton-Jones wrote: > | /tmp/Test.hs:4:1: > | The multi-parameter class `C' cannot have generic methods > | In the class declaration for `C' > > Aha. Trawling the commit logs, this test is simply a vestige of the PREVIOUS > generic-class story, now long gone. So we can lift the restriction easily. > > I'll commit a patch shortly; I hope it'll be in time for 7.4 > > Simon > > | -----Original Message----- > | From: [email protected] [mailto:glasgow-haskell- > | [email protected]] On Behalf Of Reiner Pope > | Sent: 16 January 2012 05:32 > | To: [email protected] > | Subject: DefaultSignatures and MultiParamTypeClasses > | > | Hi all, > | > | I just tried, and it appears that the new DefaultSignatures extension > doesn't > | work with multi parameter type classes. For example, when I compile this > | file: > | > | ---- > | {-# LANGUAGE DefaultSignatures, MultiParamTypeClasses #-} > | module Test where > | > | class C a b where > | conv :: a -> b > | > | default conv :: D a b => a -> b > | conv = dconv > | > | class D a b where > | dconv :: a -> b > | ----- > | > | I get the error message: > | > | ----- > | /tmp/Test.hs:4:1: > | The multi-parameter class `C' cannot have generic methods > | In the class declaration for `C' > | Failed, modules loaded: none. > | ----- > | > | Is there a reason for this restriction, or is it merely an accident? > | > | Cheers, > | Reiner > | _______________________________________________ > | Glasgow-haskell-users mailing list > | [email protected] > | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users > > _______________________________________________ Glasgow-haskell-users mailing list [email protected] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
