Richard Eisenberg authored
This introduces three new modules: - basicTypes/Predicate.hs describes predicates, moving this logic out of Type. Predicates don't really exist in Core, and so don't belong in Type. - typecheck/TcOrigin.hs describes the origin of constraints and types. It was easy to remove from other modules and can often be imported instead of other, scarier modules. - typecheck/Constraint.hs describes constraints as used in the solver. It is taken from TcRnTypes. No work other than module splitting is in this patch. This is the first step toward homogeneous equality, which will rely more strongly on predicates. And homogeneous equality is the next step toward a dependently typed core language.