Trim imports

[ghc-hetmet.git] / compiler / types / TyCon.lhs

diff --git a/compiler/types/TyCon.lhs b/compiler/types/TyCon.lhs
index b359660..f03fb89 100644 (file)
--- a/compiler/types/TyCon.lhs
+++ b/compiler/types/TyCon.lhs
@@ -61,7 +61,7 @@ module TyCon(
 
 #include "HsVersions.h"
 
-import {-# SOURCE #-} TypeRep ( Kind, Type, Coercion, PredType )
+import {-# SOURCE #-} TypeRep ( Kind, Type, PredType )
 import {-# SOURCE #-} DataCon ( DataCon, isVanillaDataCon )
 
 import Var             ( TyVar, Id )
@@ -185,8 +185,10 @@ data TyCon
        tyConUnique :: Unique,
         tyConName   :: Name,
        tyConArity  :: Arity,
-       coKindFun   :: [Type] -> Kind
-    }
+       coKindFun   :: [Type] -> (Type,Type)
+    }          -- INVARAINT: coKindFun is always applied to exactly 'arity' args
+               -- E.g. for trans (c1 :: ta=tb) (c2 :: tb=tc), the coKindFun returns 
+               --      the kind as a pair of types: (ta,tc)
        
   | SuperKindTyCon {    -- Super Kinds, TY (box) and CO (diamond).
                        -- They have no kind; and arity zero
@@ -194,10 +196,6 @@ data TyCon
         tyConName   :: Name
     }
 
-type KindCon = TyCon
-
-type SuperKindCon = TyCon
-
 type FieldLabel = Name
 
 data AlgTyConRhs
@@ -659,7 +657,7 @@ isSuperKindTyCon :: TyCon -> Bool
 isSuperKindTyCon (SuperKindTyCon {}) = True
 isSuperKindTyCon other               = False
 
-isCoercionTyCon_maybe :: TyCon -> Maybe (Arity, [Type] -> Kind)
+isCoercionTyCon_maybe :: TyCon -> Maybe (Arity, [Type] -> (Type,Type))
 isCoercionTyCon_maybe (CoercionTyCon {tyConArity = ar, coKindFun = rule}) 
   = Just (ar, rule)
 isCoercionTyCon_maybe other = Nothing