Marc you are outstanding at winkling out these bugs.
This is an erroneous program because 0 doesn't have type (forall a.a),
but it should not crash the compiler.
I've fixed it in 2.04.
Simon
| From: Marc van Dongen <[EMAIL PROTECTED]>
| Date: Thu, 29 May 1997 22:38:32 +0100 (BST)
| Compiling the code fragment appended at the end of this
| message, ghc-2.03 fails with the following output:
|
| Glasgow Haskell Compiler, version 2.03, for Haskell 1.4
|
|
| panic! (the `impossible' happened):
| tcLookupTyVar:a_r6v
| > module Group( Group ) where
|
| > import qualified Prelude( Num(..) )
| > import Prelude hiding ( Num(..) )
|
| > class Group a where
| > fromInteger :: Integer -> a
| > (-) :: a -> a -> a
| > negate :: a -> a
| > negate p
| > = (0::a) - p
|
