fix various subst_identity vs skip_binder

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -2066,7 +2066,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
  };
 
  self.one_bound_for_assoc_type(
- || traits::supertraits(tcx, ty::Binder::dummy(trait_ref.skip_binder())),
+ || traits::supertraits(tcx, ty::Binder::dummy(trait_ref.subst_identity())),
  || "Self".to_string(),
  assoc_ident,
  span,

compiler/rustc_hir_analysis/src/check/check.rs

@@ -540,7 +540,7 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
  tcx,
  it.span,
  it.owner_id.def_id,
- impl_trait_ref.skip_binder(),
+ impl_trait_ref.subst_identity(),
  &impl_.items,
  );
  check_on_unimplemented(tcx, it);

compiler/rustc_hir_analysis/src/coherence/orphan.rs

@@ -21,7 +21,7 @@ pub(crate) fn orphan_check_impl(
  tcx: TyCtxt<'_>,
  impl_def_id: LocalDefId,
 ) -> Result<(), ErrorGuaranteed> {
- let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
+ let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
  trait_ref.error_reported()?;
 
  let ret = do_orphan_check_impl(tcx, trait_ref, impl_def_id);

compiler/rustc_hir_analysis/src/coherence/unsafety.rs

@@ -13,7 +13,8 @@ pub(super) fn check_item(tcx: TyCtxt<'_>, def_id: LocalDefId) {
  let item = tcx.hir().expect_item(def_id);
  let hir::ItemKind::Impl(ref impl_) = item.kind else { bug!() };
 
- if let Some(trait_ref) = tcx.impl_trait_ref(item.owner_id).map(|t| t.subst_identity()) {
+ if let Some(trait_ref) = tcx.impl_trait_ref(item.owner_id) {
+ let trait_ref = trait_ref.subst_identity();
  let trait_def = tcx.trait_def(trait_ref.def_id);
  let unsafe_attr =
  impl_.generics.params.iter().find(|p| p.pure_wrt_drop).map(|_| "may_dangle");

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1898,9 +1898,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
  for id in tcx.hir().items() {
  if matches!(tcx.def_kind(id.owner_id), DefKind::Impl) {
- if let Some(trait_ref) =
- tcx.impl_trait_ref(id.owner_id).map(ty::EarlyBinder::subst_identity)
- {
+ if let Some(trait_ref) = tcx.impl_trait_ref(id.owner_id) {
+ let trait_ref = trait_ref.subst_identity();
+
  let simplified_self_ty = fast_reject::simplify_type(
  self.tcx,
  trait_ref.self_ty(),

compiler/rustc_middle/src/ty/mod.rs

@@ -2187,8 +2187,10 @@ impl<'tcx> TyCtxt<'tcx> {
  ) -> Option<ImplOverlapKind> {
  // If either trait impl references an error, they're allowed to overlap,
  // as one of them essentially doesn't exist.
- if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.skip_binder().references_error())
- || self.impl_trait_ref(def_id2).map_or(false, |tr| tr.skip_binder().references_error())
+ if self.impl_trait_ref(def_id1).map_or(false, |tr| tr.subst_identity().references_error())
+ || self
+ .impl_trait_ref(def_id2)
+ .map_or(false, |tr| tr.subst_identity().references_error())
  {
  return Some(ImplOverlapKind::Permitted { marker: false });
  }

compiler/rustc_monomorphize/src/collector.rs

@@ -1351,9 +1351,9 @@ fn create_mono_items_for_default_impls<'tcx>(
  tcx.def_path_str(item.owner_id.to_def_id())
  );
 
- if let Some(trait_ref) =
- tcx.impl_trait_ref(item.owner_id).map(ty::EarlyBinder::subst_identity)
- {
+ if let Some(trait_ref) = tcx.impl_trait_ref(item.owner_id) {
+ let trait_ref = trait_ref.subst_identity();
+
  let param_env = ty::ParamEnv::reveal_all();
  let trait_ref = tcx.normalize_erasing_regions(param_env, trait_ref);
  let overridden_methods = tcx.impl_item_implementor_ids(item.owner_id);

compiler/rustc_trait_selection/src/traits/coherence.rs

@@ -77,10 +77,10 @@ pub fn overlapping_impls(
  // a quick check via fast_reject to tell if the impl headers could possibly
  // unify.
  let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::AsInfer };
- let impl1_ref = tcx.impl_trait_ref(impl1_def_id).map(ty::EarlyBinder::subst_identity);
- let impl2_ref = tcx.impl_trait_ref(impl2_def_id).map(ty::EarlyBinder::subst_identity);
+ let impl1_ref = tcx.impl_trait_ref(impl1_def_id);
+ let impl2_ref = tcx.impl_trait_ref(impl2_def_id);
  let may_overlap = match (impl1_ref, impl2_ref) {
- (Some(a), Some(b)) => iter::zip(a.substs, b.substs)
+ (Some(a), Some(b)) => iter::zip(a.skip_binder().substs, b.skip_binder().substs)
  .all(|(arg1, arg2)| drcx.generic_args_may_unify(arg1, arg2)),
  (None, None) => {
  let self_ty1 = tcx.type_of(impl1_def_id);
@@ -461,7 +461,7 @@ pub fn orphan_check(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Result<(), OrphanChe
 
  // We only except this routine to be invoked on implementations
  // of a trait, not inherent implementations.
- let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
+ let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
  debug!("orphan_check: trait_ref={:?}", trait_ref);
 
  // If the *trait* is local to the crate, ok.

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

@@ -1940,7 +1940,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
  return None;
  }
 
- let imp = self.tcx.impl_trait_ref(def_id).unwrap().subst_identity();
+ let imp = self.tcx.impl_trait_ref(def_id).unwrap().skip_binder();
 
  self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false)
  .map(|similarity| ImplCandidate { trait_ref: imp, similarity })

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

@@ -431,7 +431,7 @@ fn report_conflicting_impls<'tcx>(
 pub(crate) fn to_pretty_impl_header(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Option<String> {
  use std::fmt::Write;
 
- let trait_ref = tcx.impl_trait_ref(impl_def_id)?.skip_binder();
+ let trait_ref = tcx.impl_trait_ref(impl_def_id)?.subst_identity();
  let mut w = "impl".to_owned();
 
  let substs = InternalSubsts::identity_for_item(tcx, impl_def_id);

compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs

@@ -48,7 +48,7 @@ trait ChildrenExt<'tcx> {
 impl<'tcx> ChildrenExt<'tcx> for Children {
  /// Insert an impl into this set of children without comparing to any existing impls.
  fn insert_blindly(&mut self, tcx: TyCtxt<'tcx>, impl_def_id: DefId) {
- let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
+ let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
  if let Some(st) = fast_reject::simplify_type(tcx, trait_ref.self_ty(), TreatParams::AsInfer)
  {
  debug!("insert_blindly: impl_def_id={:?} st={:?}", impl_def_id, st);
@@ -63,7 +63,7 @@ impl<'tcx> ChildrenExt<'tcx> for Children {
  /// an impl with a parent. The impl must be present in the list of
  /// children already.
  fn remove_existing(&mut self, tcx: TyCtxt<'tcx>, impl_def_id: DefId) {
- let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
+ let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
  let vec: &mut Vec<DefId>;
  if let Some(st) = fast_reject::simplify_type(tcx, trait_ref.self_ty(), TreatParams::AsInfer)
  {
@@ -275,7 +275,8 @@ impl<'tcx> GraphExt<'tcx> for Graph {
  ) -> Result<Option<FutureCompatOverlapError<'tcx>>, OverlapError<'tcx>> {
  assert!(impl_def_id.is_local());
 
- let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
+ // FIXME: use `EarlyBinder` in `self.children`
+ let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
  let trait_def_id = trait_ref.def_id;
 
  debug!(
@@ -388,7 +389,7 @@ pub(crate) fn assoc_def(
  impl_def_id: DefId,
  assoc_def_id: DefId,
 ) -> Result<LeafDef, ErrorGuaranteed> {
- let trait_def_id = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder().def_id;
+ let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap();
  let trait_def = tcx.trait_def(trait_def_id);
 
  // This function may be called while we are still building the

compiler/rustc_ty_utils/src/implied_bounds.rs

@@ -22,9 +22,9 @@ fn assumed_wf_types(tcx: TyCtxt<'_>, def_id: DefId) -> &ty::List<Ty<'_>> {
  tcx.intern_type_list(&assumed_wf_types)
  }
  DefKind::Impl => {
- match tcx.impl_trait_ref(def_id).map(ty::EarlyBinder::subst_identity) {
+ match tcx.impl_trait_ref(def_id) {
  Some(trait_ref) => {
- let types: Vec<_> = trait_ref.substs.types().collect();
+ let types: Vec<_> = trait_ref.skip_binder().substs.types().collect();
  tcx.intern_type_list(&types)
  }
  // Only the impl self type

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -786,7 +786,7 @@ fn trait_impls_for<'a>(
  tcx.find_map_relevant_impl(trait_, ty, |impl_| {
  let trait_ref = tcx.impl_trait_ref(impl_).expect("this is not an inherent impl");
  // Check if these are the same type.
- let impl_type = trait_ref.subst_identity().self_ty();
+ let impl_type = trait_ref.skip_binder().self_ty();
  trace!(
  "comparing type {} with kind {:?} against type {:?}",
  impl_type,