Break up TcRnTypes, among other modules.wip/rae/split-up-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.

3 files changed, 5 insertions, 4 deletions

diff --git a/compiler/rename/RnBinds.hs b/compiler/rename/RnBinds.hs
index 56caee1a2a..9b93af907b 100644
--- a/compiler/rename/RnBinds.hs
+++ b/compiler/rename/RnBinds.hs
@@ -49,7 +49,7 @@ import NameSet
 import RdrName          ( RdrName, rdrNameOcc )
 import SrcLoc
 import ListSetOps       ( findDupsEq )
-import BasicTypes       ( RecFlag(..) )
+import BasicTypes       ( RecFlag(..), TypeOrKind(..) )
 import Digraph          ( SCC(..) )
 import Bag
 import Util
diff --git a/compiler/rename/RnSource.hs b/compiler/rename/RnSource.hs
index 1ab80e755a..b59faa5f4d 100644
--- a/compiler/rename/RnSource.hs
+++ b/compiler/rename/RnSource.hs
@@ -52,7 +52,7 @@ import NameEnv
 import Avail
 import Outputable
 import Bag
-import BasicTypes       ( pprRuleName )
+import BasicTypes       ( pprRuleName, TypeOrKind(..) )
 import FastString
 import SrcLoc
 import DynFlags
diff --git a/compiler/rename/RnTypes.hs b/compiler/rename/RnTypes.hs
index 5f0a1c62c7..425b78d2ed 100644
--- a/compiler/rename/RnTypes.hs
+++ b/compiler/rename/RnTypes.hs
@@ -57,8 +57,9 @@ import FieldLabel
 
 import Util
 import ListSetOps       ( deleteBys )
-import BasicTypes       ( compareFixity, funTyFixity, negateFixity,
-                          Fixity(..), FixityDirection(..), LexicalFixity(..) )
+import BasicTypes       ( compareFixity, funTyFixity, negateFixity
+                        , Fixity(..), FixityDirection(..), LexicalFixity(..)
+                        , TypeOrKind(..) )
 import Outputable
 import FastString
 import Maybes