Thanks for the bug report.
Yes the template-haskell mailing list should work. I'm ccing it.
| I compiled the following program with ghc-5.05.20030109
|
| ----------
|
| import Language.Haskell.THSyntax
|
| main = putStrLn (show $(lift ('a', 'b')))
|
| instance (Lift a, Lift b) => Lift (a,b) where
| lift (a,b) = tup [lift a, lift b]
|
| -----
|
| and received the following error message
|
| ghc-5.05.20030109: panic! (the `impossible' happened, GHC version
| 5.05.20030109):
| nameModule zdfLiftZ2T{-a1dB-}
Well, the error message is appalling, and I'll improve it forthwith, but
the reason is simple: GHC doesn't allow you to call a locally-defined
function inside a top-level splice. (It makes sense, but requires GHC
to compile code inconveniently early, for the module being compiled.)
So you have to put the instance decl in a separate module and compile
that first.
The error message will say so, shortly.
Simon
