Rollup merge of rust-lang#108133 - kylematsuda:earlybinder-cleanups, r=compiler-errors

Small cleanups around `EarlyBinder`

Cleaning up a few things that were brought up by `@lcnr` in reviewing rust-lang#106696:

- [make `issue33140_self_ty` query return `Option<EarlyBinder<Ty>>`](rust-lang#106696 (comment))
- [small style improvement](rust-lang#106696 (comment))

Author: matthiaskrgr

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1541,8 +1541,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 self.tables.impl_defaultness.set_some(def_id.index, *defaultness);
                 self.tables.constness.set_some(def_id.index, *constness);
 
-                let trait_ref = self.tcx.impl_trait_ref(def_id).map(ty::EarlyBinder::skip_binder);
+                let trait_ref = self.tcx.impl_trait_ref(def_id);
                 if let Some(trait_ref) = trait_ref {
+                    let trait_ref = trait_ref.skip_binder();
                     let trait_def = self.tcx.trait_def(trait_ref.def_id);
                     if let Ok(mut an) = trait_def.ancestors(self.tcx, def_id) {
                         if let Some(specialization_graph::Node::Impl(parent)) = an.nth(1) {

compiler/rustc_middle/src/query/mod.rs

@@ -781,7 +781,7 @@ rustc_queries! {
         separate_provide_extern
     }
 
-    query issue33140_self_ty(key: DefId) -> Option<ty::Ty<'tcx>> {
+    query issue33140_self_ty(key: DefId) -> Option<ty::EarlyBinder<ty::Ty<'tcx>>> {
         desc { |tcx| "computing Self type wrt issue #33140 `{}`", tcx.def_path_str(key) }
     }
 

compiler/rustc_ty_utils/src/ty.rs

@@ -1,7 +1,9 @@
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir as hir;
 use rustc_index::bit_set::BitSet;
-use rustc_middle::ty::{self, Binder, Predicate, PredicateKind, ToPredicate, Ty, TyCtxt};
+use rustc_middle::ty::{
+    self, Binder, EarlyBinder, Predicate, PredicateKind, ToPredicate, Ty, TyCtxt,
+};
 use rustc_session::config::TraitSolver;
 use rustc_span::def_id::{DefId, CRATE_DEF_ID};
 use rustc_trait_selection::traits;
@@ -355,7 +357,7 @@ fn instance_def_size_estimate<'tcx>(
 /// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
 ///
 /// See [`ty::ImplOverlapKind::Issue33140`] for more details.
-fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
+fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<EarlyBinder<Ty<'_>>> {
     debug!("issue33140_self_ty({:?})", def_id);
 
     let trait_ref = tcx
@@ -394,7 +396,7 @@ fn issue33140_self_ty(tcx: TyCtxt<'_>, def_id: DefId) -> Option<Ty<'_>> {
 
     if self_ty_matches {
         debug!("issue33140_self_ty - MATCHES!");
-        Some(self_ty)
+        Some(EarlyBinder(self_ty))
     } else {
         debug!("issue33140_self_ty - non-matching self type");
         None