Make EarlyBinder's inner value private; and fix all of the resulting errors

compiler/rustc_middle/src/ty/print/mod.rs

@@ -123,7 +123,7 @@ pub trait Printer<'tcx>: Sized {
                         impl_trait_ref.map(|i| i.subst(self.tcx(), substs)),
                     )
                 } else {
-                    (self_ty.0, impl_trait_ref.map(|i| i.0))
+                    (self_ty.subst_identity(), impl_trait_ref.map(|i| i.subst_identity()))
                 };
                 self.print_impl_path(def_id, substs, self_ty, impl_trait_ref)
             }

compiler/rustc_middle/src/ty/sty.rs

@@ -2366,7 +2366,7 @@ impl<'tcx> Ty<'tcx> {
 
             ty::Tuple(tys) => tys.iter().all(|ty| ty.is_trivially_sized(tcx)),
 
-            ty::Adt(def, _substs) => def.sized_constraint(tcx).0.is_empty(),
+            ty::Adt(def, _substs) => def.sized_constraint(tcx).skip_binder().is_empty(),
 
             ty::Alias(..) | ty::Param(_) | ty::Placeholder(..) => false,
 

compiler/rustc_middle/src/ty/subst.rs

@@ -538,7 +538,7 @@ impl<'tcx, T: TypeVisitable<TyCtxt<'tcx>>> TypeVisitable<TyCtxt<'tcx>> for &'tcx
 /// [`subst_identity`](EarlyBinder::subst_identity) or [`skip_binder`](EarlyBinder::skip_binder).
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 #[derive(Encodable, Decodable, HashStable)]
-pub struct EarlyBinder<T>(pub T);
+pub struct EarlyBinder<T>(T);
 
 /// For early binders, you should first call `subst` before using any visitors.
 impl<'tcx, T> !TypeFoldable<TyCtxt<'tcx>> for ty::EarlyBinder<T> {}