In GHC 6.2, Template Haskell has various bugs. I think they are all fixed in the HEAD, so you can either build from source or grab a development snapshot from the GHC site. The HEAD version of TH has a slightly different programming interface too -- see http://research.microsoft.com/~simonpj/tmp/notes2.ps Simon | -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users- | bounces@haskell.org] On Behalf Of Jeremy Shaw | Sent: 31 December 2003 02:19 | To: glasgow-haskell-users@haskell.org | Subject: classes and template haskell (bug?) | | Hello, | | I have loaded the following from a file into ghci 6.2: | | module Main where | | import Language.Haskell.THSyntax | | class Test a where | test :: a -> a | | instance Test (a,b,c) where | test x = x | | main = putStrLn "Hello, World!" | | This works for me: | | *Main> runQ [d| instance Test (Int,Int) |] >>= putStrLn . show | [InstanceD [] (AppT (ConT "Main:Test") (AppT (AppT (TupleT 2) (ConT "GHC.Base:Int")) (ConT | "GHC.Base:Int"))) []] | | But this doesn't: | | *Main> runQ [d| instance Test (a,b) |] >>= putStrLn . show | ghc-6.2: panic! (the `impossible' happened, GHC version 6.2): | Failed binder lookup: a {- tv a20x -} | | Please report it as a compiler bug to glasgow-haskell-bugs@haskell.org, | or http://sourceforge.net/projects/ghc/. | | | Am I doing something wrong, or is this a bug? | | Thanks! | Jeremy Shaw. | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users