classes and template haskell (bug?)

[Jeremy Shaw]

Hello,

No dice. Using cvs head from 12/31, I get the same behavior, (plus a
new bug). Using the same test as before (after updating the import
line):

*Main> runQ [d| instance Test (a,b) |] >>= putStrLn . show
ghc-6.3: panic! (the `impossible' happened, GHC version 6.3):
	Failed binder lookup: a{tv} {- tv a2jx -}

Please report it as a compiler bug to glasgow-haskell-bugs at haskell.org,
or http://sourceforge.net/projects/ghc/.

Also, a new bug has appeared (then again, it is cvs head) -- If I
start ghci, and then do this:

Prelude> let n = 1
Prelude> n
*** Exception: basicTypes/Var.lhs:226:32-58: Non-exhaustive patterns in record update

Prelude> b
*** Exception: basicTypes/Var.lhs:226:32-58: Non-exhaustive patterns in record update

Prelude> a
*** Exception: basicTypes/Var.lhs:226:32-58: Non-exhaustive patterns in record update

Prelude> 3 + 4
*** Exception: basicTypes/Var.lhs:226:32-58: Non-exhaustive patterns in record update


Or similarily:

*Main> runQ [d| instance Test (Int,Int) |] >>= putStrLn . show
Loading package haskell98 ... linking ... done.
Loading package haskell-src ... linking ... done.
[InstanceD [] (AppT (ConT Main.Test) (AppT (AppT (TupleT 2) (ConT GHC.Base.Int)) (ConT GHC.Base.Int))) []]
*Main> runQ [d| instance Test (a,b) |] >>= putStrLn . show
*** Exception: basicTypes/Var.lhs:226:32-58: Non-exhaustive patterns in record update

Jeremy Shaw.


At Wed, 31 Dec 2003 08:11:47 -0000,
Simon Peyton-Jones wrote:
> 
> 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 at haskell.org
> [mailto:glasgow-haskell-users-
> | bounces at haskell.org] On Behalf Of Jeremy Shaw
> | Sent: 31 December 2003 02:19
> | To: glasgow-haskell-users at 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 at haskell.org,
> | or http://sourceforge.net/projects/ghc/.
> | 
> | 
> | Am I doing something wrong, or is this a bug?
> | 
> | Thanks!
> | Jeremy Shaw.
> | _______________________________________________
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>