HEADS-UP: diagrams does not compile with HEAD (regressions)

Jan Stolarek jan.stolarek at p.lodz.pl
Tue Jun 10 16:16:02 UTC 2014


Reid is correct. This is a result of fixing #8883. I agree that printing the inferred signature 
sounds like a good idea.

Janek

Dnia wtorek, 10 czerwca 2014, Reid Barton napisał:
> I expect this is a result of https://ghc.haskell.org/trac/ghc/ticket/8883,
> but even so it's not clear to me whether the error is correct. It would be
> nice if GHC printed the type it inferred for succ' in this kind of
> situation.
>
> Regards,
> Reid Barton
>
> On Tue, Jun 10, 2014 at 7:55 AM, Gabor Greif <ggreif at gmail.com> wrote:
> > Devs,
> >
> > as of recently GHC HEAD stopped building the diagrams library. Several
> > prerequisite libs also fail to compile. A specific error message
> > appears in an attoparsec issue
> > <https://github.com/bos/attoparsec/issues/67>, for which I have
> > submitted a workaround. But as Herbert cautiously points out, this
> > could be a recent GHC bug surfacing.
> >
> > The symptoms of the bug seem to be that GHC complains about the usage
> > of (~) type equality operation, but there is no reference to that type
> > operator in the source code. To work around the problem it suffices to
> > add -XGADTs or -XTypeFamilies.
> >
> > Does this ring any bells? Can automatized tests catch such things in the
> > future?
> >
> > Cheers,
> >
> >     Gabor
> > _______________________________________________
> > ghc-devs mailing list
> > ghc-devs at haskell.org
> > http://www.haskell.org/mailman/listinfo/ghc-devs




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