On Thu, Apr 10, 2014 at 1:59 PM, Felipe Lessa <felipe.lessa@gmail.com> wrote:
Em 10-04-2014 14:45, Brandon Allbery escreveu:
> It "should be" but I suspect actually treating it as one is rather
> difficult now that it's possible for `a` there to be a Constraint or
> etc., in which case it is on the correct side of the =>.

What you're saying is that it would be difficult to ban this on the
parser level.  However, somewhere inside GHC this `a` that was used as a
constraint got promoted to being an argument.  This is where it should
have been stopped on its track.

Actually, what I'm saying is that it might be difficult to reliably catch it at that point; consider that the parse leading to that interpretation may not exist within ghc at that point, only an AST that may have been rearranged by uses of ConstraintKinds so as to lose its direct relationship to the parse that initially led to it.

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