ghc7 typing problem

Christian Maeder Christian.Maeder at dfki.de
Mon Oct 25 08:09:40 EDT 2010


Again thanks, it works with ghc 7.1.20101024

C.

Am 18.10.2010 18:16, schrieb Simon Peyton-Jones:
> Thanks.  We knew about this -- in flight changes happening now -- but I've added it as a new regression test even so.
> 
> Simon
> 
> | -----Original Message-----
> | From: Christian Maeder [mailto:Christian.Maeder at dfki.de]
> | Sent: 15 October 2010 17:53
> | To: GHC Users Mailing List
> | Cc: Simon Peyton-Jones
> | Subject: ghc7 typing problem
> | 
> | Hi,
> | 
> | I've looked at:
> | http://hackage.haskell.org/trac/ghc/blog/LetGeneralisationInGhc7
> | 
> | but still have a problem with the attached program that fails with:
> | 
> | GHCi, version 7.1.20101010: http://www.haskell.org/ghc/  :? for help Loading package
> | ghc-prim ... linking ... done.
> | Loading package integer-gmp ... linking ... done.
> | Loading package base ... linking ... done.
> | Loading package ffi-1.0 ... linking ... done.
> | [1 of 1] Compiling Main             ( HasKey.hs, interpreted )
> | 
> | HasKey.hs:17:10:
> |     Couldn't match type `key' with `key1'
> |       because this skolem type variable would escape: `key1'
> |     This skolem is bound by the instance declaration
> |     In the instance declaration for `Ord (Keyed x)'
> | 
> | at the final instance for Ord.
> | 
> | The original code comes from
> | http://hackage.haskell.org/packages/archive/uni-util/2.2.0.0/doc/html/Util-
> | VariableSet.html
> | 
> | Cheers Christian


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