I can't file a trac ticket at the meny but wanted to see if this is a
bug... This is an excerpt from llvm-general that compiles on 7.6.3 but
doesn't without ImpredicativeTypes enabled on HEAD:
I would say you do indeed need impredicative types to compile the instance you request -- you need to instantiate a type variable with a forall-type. But, whether or not we should require users to actually specify ImpredicativeTypes to compile code that we're generating is another question. And, the error message is terrible, regardless.
Thanks for bringing this up!
On Dec 26, 2013, at 10:30 PM, Nathan Howell <nathan.d.howell at gmail.com> wrote: