Please say which version of GHC you are using. This program works fine with GHC 5.02.2
Simon | -----Original Message----- | From: Hal Daume III [mailto:[EMAIL PROTECTED]] | Sent: 22 August 2002 20:47 | To: [EMAIL PROTECTED] | Subject: bug with rank n polymorphism in classes | | | consider: | | module Foo where | | class Foo p where | foo :: p -> (forall q . Foo q => q -> a) -> a | | instance Foo Int where | | | if you load this in to ghci, it complains: | | /home/hdaume/projects/NLP/Foo.hs:6: | Ambiguous type variable(s) `q' in the constraint `Foo q' | arising from a function with an overloaded argument type | at /home/hdaume/projects/NLP/Foo.hs:6 | Expected type: Int -> (forall q1. (Foo q1) => q1 -> a) -> a | Inferred type: Int -> (q -> a) -> a | In the application `GHC.Err.noMethodBindingError | "/home/hdaume/projects/NLP/Foo.hs:6|Foo.foo"#' | | which is a reasonable complaint, but is emiited in a rather | bizzare way. | | -- | Hal Daume III | | "Computer science is no more about computers | [EMAIL PROTECTED] | than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume | | _______________________________________________ | Glasgow-haskell-bugs mailing list | [EMAIL PROTECTED] | http://www.haskell.org/mailman/listinfo/glasgow-| haskell-bugs | _______________________________________________ Glasgow-haskell-bugs mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
