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, 1 insertions, 1 deletions

diff --git a/testsuite/tests/driver/werror.stderr b/testsuite/tests/driver/werror.stderr
index 8f2e6035db..ae18bb62f0 100644
--- a/testsuite/tests/driver/werror.stderr
+++ b/testsuite/tests/driver/werror.stderr
@@ -18,7 +18,7 @@ werror.hs:10:1: warning: [-Wunused-top-binds (in -Wextra, -Wunused-binds)]
 
 werror.hs:10:1: warning: [-Wmissing-signatures (in -Wall)]
     Top-level binding with no type signature:
-      f :: forall t t1. [t1] -> [t]
+      f :: forall a a1. [a1] -> [a]
 
 werror.hs:10:1: warning: [-Wincomplete-patterns (in -Wextra)]
     Pattern match(es) are non-exhaustive