Break up TcRnTypes, among other modules.

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.

1 files changed, 1 insertions, 0 deletions

diff --git a/compiler/stranal/WwLib.hs b/compiler/stranal/WwLib.hs
index 5e4d22857a..f8b398fbcd 100644
--- a/compiler/stranal/WwLib.hs
+++ b/compiler/stranal/WwLib.hs
@@ -30,6 +30,7 @@ import Literal          ( absentLiteralOf, rubbishLit )
 import VarEnv           ( mkInScopeSet )
 import VarSet           ( VarSet )
 import Type
+import Predicate        ( isClassPred )
 import RepType          ( isVoidTy, typePrimRep )
 import Coercion
 import FamInstEnv