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

compiler/rustc_hir_analysis/src/outlives/implicit_infer.rs

@@ -68,8 +68,9 @@ pub(super) fn infer_predicates(
             // Therefore mark `predicates_added` as true and which will ensure
             // we walk the crates again and re-calculate predicates for all
             // items.
-            let item_predicates_len: usize =
-                global_inferred_outlives.get(&item_did.to_def_id()).map_or(0, |p| p.0.len());
+            let item_predicates_len: usize = global_inferred_outlives
+                .get(&item_did.to_def_id())
+                .map_or(0, |p| p.as_ref().skip_binder().len());
             if item_required_predicates.len() > item_predicates_len {
                 predicates_added = true;
                 global_inferred_outlives
@@ -137,7 +138,9 @@ fn insert_required_predicates_to_be_wf<'tcx>(
                 // 'a` holds for `Foo`.
                 debug!("Adt");
                 if let Some(unsubstituted_predicates) = global_inferred_outlives.get(&def.did()) {
-                    for (unsubstituted_predicate, &span) in &unsubstituted_predicates.0 {
+                    for (unsubstituted_predicate, &span) in
+                        unsubstituted_predicates.as_ref().skip_binder()
+                    {
                         // `unsubstituted_predicate` is `U: 'b` in the
                         // example above. So apply the substitution to
                         // get `T: 'a` (or `predicate`):
@@ -251,7 +254,7 @@ fn check_explicit_predicates<'tcx>(
     );
     let explicit_predicates = explicit_map.explicit_predicates_of(tcx, def_id);
 
-    for (outlives_predicate, &span) in &explicit_predicates.0 {
+    for (outlives_predicate, &span) in explicit_predicates.as_ref().skip_binder() {
         debug!("outlives_predicate = {:?}", &outlives_predicate);
 
         // Careful: If we are inferring the effects of a `dyn Trait<..>`

compiler/rustc_hir_analysis/src/outlives/mod.rs

@@ -98,24 +98,27 @@ fn inferred_outlives_crate(tcx: TyCtxt<'_>, (): ()) -> CratePredicatesMap<'_> {
     let predicates = global_inferred_outlives
         .iter()
         .map(|(&def_id, set)| {
-            let predicates = &*tcx.arena.alloc_from_iter(set.0.iter().filter_map(
-                |(ty::OutlivesPredicate(kind1, region2), &span)| {
-                    match kind1.unpack() {
-                        GenericArgKind::Type(ty1) => Some((
-                            ty::Clause::TypeOutlives(ty::OutlivesPredicate(ty1, *region2)),
-                            span,
-                        )),
-                        GenericArgKind::Lifetime(region1) => Some((
-                            ty::Clause::RegionOutlives(ty::OutlivesPredicate(region1, *region2)),
-                            span,
-                        )),
-                        GenericArgKind::Const(_) => {
-                            // Generic consts don't impose any constraints.
-                            None
+            let predicates =
+                &*tcx.arena.alloc_from_iter(set.as_ref().skip_binder().iter().filter_map(
+                    |(ty::OutlivesPredicate(kind1, region2), &span)| {
+                        match kind1.unpack() {
+                            GenericArgKind::Type(ty1) => Some((
+                                ty::Clause::TypeOutlives(ty::OutlivesPredicate(ty1, *region2)),
+                                span,
+                            )),
+                            GenericArgKind::Lifetime(region1) => Some((
+                                ty::Clause::RegionOutlives(ty::OutlivesPredicate(
+                                    region1, *region2,
+                                )),
+                                span,
+                            )),
+                            GenericArgKind::Const(_) => {
+                                // Generic consts don't impose any constraints.
+                                None
+                            }
                         }
-                    }
-                },
-            ));
+                    },
+                ));
             (def_id, predicates)
         })
         .collect();

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -1386,7 +1386,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // the referenced item.
         let ty = tcx.type_of(def_id);
         assert!(!substs.has_escaping_bound_vars());
-        assert!(!ty.0.has_escaping_bound_vars());
+        assert!(!ty.skip_binder().has_escaping_bound_vars());
         let ty_substituted = self.normalize(span, ty.subst(tcx, substs));
 
         if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {

compiler/rustc_infer/src/infer/outlives/verify.rs

@@ -293,7 +293,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
     ) -> impl Iterator<Item = ty::Region<'tcx>> {
         let tcx = self.tcx;
         let bounds = tcx.item_bounds(alias_ty.def_id);
-        trace!("{:#?}", bounds.0);
+        trace!("{:#?}", bounds.skip_binder());
         bounds
             .subst_iter(tcx, alias_ty.substs)
             .filter_map(|p| p.to_opt_type_outlives())

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> {}

compiler/rustc_mir_transform/src/shim.rs

@@ -644,8 +644,11 @@ fn build_call_shim<'tcx>(
     let sig = sig.map_bound(|sig| tcx.erase_late_bound_regions(sig));
 
     assert_eq!(sig_substs.is_some(), !instance.has_polymorphic_mir_body());
-    let mut sig =
-        if let Some(sig_substs) = sig_substs { sig.subst(tcx, &sig_substs) } else { sig.0 };
+    let mut sig = if let Some(sig_substs) = sig_substs {
+        sig.subst(tcx, &sig_substs)
+    } else {
+        sig.skip_binder()
+    };
 
     if let CallKind::Indirect(fnty) = call_kind {
         // `sig` determines our local decls, and thus the callee type in the `Call` terminator. This

compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs

@@ -148,11 +148,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
 
         ty::Adt(def, substs) => {
             let sized_crit = def.sized_constraint(ecx.tcx());
-            Ok(sized_crit
-                .0
-                .iter()
-                .map(|ty| sized_crit.rebind(*ty).subst(ecx.tcx(), substs))
-                .collect())
+            Ok(sized_crit.subst_iter_copied(ecx.tcx(), substs).collect())
         }
     }
 }

compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs

@@ -360,7 +360,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 // consider a "quick reject". This avoids creating more types
                 // and so forth that we need to.
                 let impl_trait_ref = self.tcx().impl_trait_ref(impl_def_id).unwrap();
-                if !drcx.substs_refs_may_unify(obligation_substs, impl_trait_ref.0.substs) {
+                if !drcx
+                    .substs_refs_may_unify(obligation_substs, impl_trait_ref.skip_binder().substs)
+                {
                     return;
                 }
                 if self.reject_fn_ptr_impls(

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -527,9 +527,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                         substs.extend(trait_predicate.trait_ref.substs.iter());
                         let mut bound_vars: smallvec::SmallVec<[ty::BoundVariableKind; 8]> =
                             smallvec::SmallVec::with_capacity(
-                                bound.0.kind().bound_vars().len() + defs.count(),
+                                bound.skip_binder().kind().bound_vars().len() + defs.count(),
                             );
-                        bound_vars.extend(bound.0.kind().bound_vars().into_iter());
+                        bound_vars.extend(bound.skip_binder().kind().bound_vars().into_iter());
                         InternalSubsts::fill_single(&mut substs, defs, &mut |param, _| match param
                             .kind
                         {

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -2149,13 +2149,11 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
             ty::Adt(def, substs) => {
                 let sized_crit = def.sized_constraint(self.tcx());
                 // (*) binder moved here
-                Where(obligation.predicate.rebind({
-                    sized_crit
-                        .0
-                        .iter()
-                        .map(|ty| sized_crit.rebind(*ty).subst(self.tcx(), substs))
-                        .collect()
-                }))
+                Where(
+                    obligation
+                        .predicate
+                        .rebind(sized_crit.subst_iter_copied(self.tcx(), substs).collect()),
+                )
             }
 
             ty::Alias(..) | ty::Param(_) | ty::Placeholder(..) => None,

compiler/rustc_traits/src/chalk/db.rs

@@ -294,7 +294,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
         };
         Arc::new(chalk_solve::rust_ir::FnDefDatum {
             id: fn_def_id,
-            sig: sig.0.lower_into(self.interner),
+            sig: sig.skip_binder().lower_into(self.interner),
             binders: chalk_ir::Binders::new(binders, bound),
         })
     }

compiler/rustc_ty_utils/src/ty.rs

@@ -44,9 +44,7 @@ fn sized_constraint_for_ty<'tcx>(
             let adt_tys = adt.sized_constraint(tcx);
             debug!("sized_constraint_for_ty({:?}) intermediate = {:?}", ty, adt_tys);
             adt_tys
-                .0
-                .iter()
-                .map(|ty| adt_tys.rebind(*ty).subst(tcx, substs))
+                .subst_iter_copied(tcx, substs)
                 .flat_map(|ty| sized_constraint_for_ty(tcx, adtdef, ty))
                 .collect()
         }

src/librustdoc/clean/blanket_impl.rs

@@ -21,7 +21,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
         let mut impls = Vec::new();
         for trait_def_id in cx.tcx.all_traits() {
             if !cx.cache.effective_visibilities.is_reachable(cx.tcx, trait_def_id)
-                || cx.generated_synthetics.get(&(ty.0, trait_def_id)).is_some()
+                || cx.generated_synthetics.get(&(ty.skip_binder(), trait_def_id)).is_some()
             {
                 continue;
             }
@@ -34,7 +34,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                     impl_def_id
                 );
                 let trait_ref = cx.tcx.impl_trait_ref(impl_def_id).unwrap();
-                if !matches!(trait_ref.0.self_ty().kind(), ty::Param(_)) {
+                if !matches!(trait_ref.skip_binder().self_ty().kind(), ty::Param(_)) {
                     continue;
                 }
                 let infcx = cx.tcx.infer_ctxt().build();
@@ -87,7 +87,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                     trait_ref, ty
                 );
 
-                cx.generated_synthetics.insert((ty.0, trait_def_id));
+                cx.generated_synthetics.insert((ty.skip_binder(), trait_def_id));
 
                 impls.push(Item {
                     name: None,
@@ -104,10 +104,10 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                         // the post-inference `trait_ref`, as it's more accurate.
                         trait_: Some(clean_trait_ref_with_bindings(
                             cx,
-                            ty::Binder::dummy(trait_ref.0),
+                            ty::Binder::dummy(trait_ref.skip_binder()),
                             ThinVec::new(),
                         )),
-                        for_: clean_middle_ty(ty::Binder::dummy(ty.0), cx, None),
+                        for_: clean_middle_ty(ty::Binder::dummy(ty.skip_binder()), cx, None),
                         items: cx
                             .tcx
                             .associated_items(impl_def_id)
@@ -116,7 +116,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                             .collect::<Vec<_>>(),
                         polarity: ty::ImplPolarity::Positive,
                         kind: ImplKind::Blanket(Box::new(clean_middle_ty(
-                            ty::Binder::dummy(trait_ref.0.self_ty()),
+                            ty::Binder::dummy(trait_ref.skip_binder().self_ty()),
                             cx,
                             None,
                         ))),

src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs

@@ -138,7 +138,7 @@ fn collect_unsafe_exprs<'tcx>(
                     .type_dependent_def_id(expr.hir_id)
                     .map(|def_id| cx.tcx.fn_sig(def_id))
                 {
-                    if sig.0.unsafety() == Unsafety::Unsafe {
+                    if sig.skip_binder().unsafety() == Unsafety::Unsafe {
                         unsafe_ops.push(("unsafe method call occurs here", expr.span));
                     }
                 }