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@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