[Haskell-cafe] template haskell overly conservative during splicing?

[Simon Peyton-Jones]

Thanks for the bug report. I've fixed the bug: see
http://hackage.haskell.org/trac/ghc/ticket/2817

Simon
| -----Original Message-----
| From: haskell-cafe-bounces at haskell.org [mailto:haskell-cafe-bounces at haskell.org] On Behalf Of
| Nicolas Frisby
| Sent: 04 November 2008 01:03
| To: haskell Cafe
| Subject: [Haskell-cafe] template haskell overly conservative during splicing?
|
| When using template haskell (via Derive) to generate this (exact) instance:
|
|   instance Foldable ((->) Int) => Foldable
| Data.Derivable.InterpreterLib.Test.List
|       where foldMap f (Cons x0 x1) = (const mempty Cons `mappend`
| foldMap f x0) `mappend` foldMap f x1
|             foldMap f (Nil) = const mempty Nil
|
| I realize the context is insatisfiable. My issue, is that I can't even
| reach that "challenge". I get this error instead:
|
|    Malformed type AppT ArrowT (ConT GHC.Base.Int)
|     When splicing generated code into the program
|
| I couldn't find an existing ticket or discussion for this issue
| relying on the phrase "malformed type". I couldn't even find the
| source that generates that string in haskell-src, template-haskell, or
| ghc-6.8.2. Can anybody help?
|
| Thanks for your time.
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