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.