Thanks for the fine bug report. It'll be fixed in the next release.
Simon
> I found a compiler bug in 'ghc', it came up as follows: forgetting a
> definition, e.g. 'atMost', in a signature, but still keeping a default method
> for 'atMost' should produce something like
>
> TestADT.lhs:56: Value not in scope: `atMost'
>
> But with the appended source ('TestADT.lhs') ghc gave the message
>
> panic! (the `impossible' happened):
> classOpTagByOccName PriorityQueue{-r3O,x-} atMost
>
> Please report it as a compiler bug to [EMAIL PROTECTED]
