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
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@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs