Major patch to introduce TyConBinder

Before this patch, following the TypeInType innovations,
each TyCon had two lists:
  - tyConBinders :: [TyBinder]
  - tyConTyVars  :: [TyVar]

They were in 1-1 correspondence and contained
overlapping information.  More broadly, there were many
places where we had to pass around this pair of lists,
instead of a single list.

This commit tidies all that up, by having just one list of
binders in a TyCon:

  - tyConBinders :: [TyConBinder]

The new data types look like this:

  Var.hs:
     data TyVarBndr tyvar vis = TvBndr tyvar vis
     data VisibilityFlag = Visible | Specified | Invisible
     type TyVarBinder = TyVarBndr TyVar VisibilityFlag

  TyCon.hs:
     type TyConBinder = TyVarBndr TyVar TyConBndrVis

     data TyConBndrVis
       = NamedTCB VisibilityFlag
       | AnonTCB

  TyCoRep.hs:
     data TyBinder
       = Named TyVarBinder
       | Anon Type

Note that Var.TyVarBdr has moved from TyCoRep and has been
made polymorphic in the tyvar and visiblity fields:

     type TyVarBinder = TyVarBndr TyVar VisibilityFlag
        -- Used in ForAllTy
     type TyConBinder = TyVarBndr TyVar TyConBndrVis
        -- Used in TyCon

     type IfaceForAllBndr  = TyVarBndr IfaceTvBndr VisibilityFlag
     type IfaceTyConBinder = TyVarBndr IfaceTvBndr TyConBndrVis
         -- Ditto, in interface files

There are a zillion knock-on changes, but everything
arises from these types.  It was a bit fiddly to get the
module loops to work out right!

Some smaller points
~~~~~~~~~~~~~~~~~~~
* Nice new functions
    TysPrim.mkTemplateKiTyVars
    TysPrim.mkTemplateTyConBinders
  which help you make the tyvar binders for dependently-typed
  TyCons.  See comments with their definition.

* The change showed up a bug in TcGenGenerics.tc_mkRepTy, where the code
  was making an assumption about the order of the kind variables in the
  kind of GHC.Generics.(:.:).  I fixed this; see TcGenGenerics.mkComp.

1 files changed, 19 insertions, 19 deletions

diff --git a/testsuite/tests/typecheck/should_fail/tcfail201.stderr b/testsuite/tests/typecheck/should_fail/tcfail201.stderr
index 9df11cafff..77349e29f4 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail201.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail201.stderr
@@ -1,19 +1,19 @@
-

-tcfail201.hs:17:56: error:

-    • Couldn't match type ‘a’ with ‘HsDoc t0’

-      ‘a’ is a rigid type variable bound by

-        the type signature for:

-          gfoldl' :: forall (c :: * -> *) a.

-                     (forall a1 b. c (a1 -> b) -> a1 -> c b)

-                     -> (forall g. g -> c g) -> a -> c a

-        at tcfail201.hs:15:1-85

-      Expected type: c a

-        Actual type: c (HsDoc t0)

-    • In the expression: z DocEmpty

-      In a case alternative: DocEmpty -> z DocEmpty

-      In the expression: case hsDoc of { DocEmpty -> z DocEmpty }

-    • Relevant bindings include

-        hsDoc :: a (bound at tcfail201.hs:16:13)

-        gfoldl' :: (forall a1 b. c (a1 -> b) -> a1 -> c b)

-                   -> (forall g. g -> c g) -> a -> c a

-          (bound at tcfail201.hs:16:1)

+
+tcfail201.hs:17:56: error:
+    • Couldn't match type ‘a’ with ‘HsDoc id0’
+      ‘a’ is a rigid type variable bound by
+        the type signature for:
+          gfoldl' :: forall (c :: * -> *) a.
+                     (forall a1 b. c (a1 -> b) -> a1 -> c b)
+                     -> (forall g. g -> c g) -> a -> c a
+        at tcfail201.hs:15:1-85
+      Expected type: c a
+        Actual type: c (HsDoc id0)
+    • In the expression: z DocEmpty
+      In a case alternative: DocEmpty -> z DocEmpty
+      In the expression: case hsDoc of { DocEmpty -> z DocEmpty }
+    • Relevant bindings include
+        hsDoc :: a (bound at tcfail201.hs:16:13)
+        gfoldl' :: (forall a1 b. c (a1 -> b) -> a1 -> c b)
+                   -> (forall g. g -> c g) -> a -> c a
+          (bound at tcfail201.hs:16:1)