Merging upstream version 1.68.2+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 168 insertions, 104 deletions

diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 2a2a9470d..0f0e16265 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -22,6 +22,7 @@ use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
 use rustc_middle::middle::resolve_lifetime as rl;
 use rustc_middle::ty::fold::TypeFolder;
 use rustc_middle::ty::InternalSubsts;
+use rustc_middle::ty::TypeVisitable;
 use rustc_middle::ty::{self, AdtKind, DefIdTree, EarlyBinder, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
 use rustc_span::hygiene::{AstPass, MacroKind};
@@ -127,7 +128,7 @@ fn clean_generic_bound<'tcx>(
         hir::GenericBound::LangItemTrait(lang_item, span, _, generic_args) => {
             let def_id = cx.tcx.require_lang_item(lang_item, Some(span));
 
-            let trait_ref = ty::TraitRef::identity(cx.tcx, def_id).skip_binder();
+            let trait_ref = ty::TraitRef::identity(cx.tcx, def_id);
 
             let generic_args = clean_generic_args(generic_args, cx);
             let GenericArgs::AngleBracketed { bindings, .. } = generic_args
@@ -156,17 +157,18 @@ fn clean_generic_bound<'tcx>(
 
 pub(crate) fn clean_trait_ref_with_bindings<'tcx>(
     cx: &mut DocContext<'tcx>,
-    trait_ref: ty::TraitRef<'tcx>,
+    trait_ref: ty::PolyTraitRef<'tcx>,
     bindings: ThinVec<TypeBinding>,
 ) -> Path {
-    let kind = cx.tcx.def_kind(trait_ref.def_id).into();
+    let kind = cx.tcx.def_kind(trait_ref.def_id()).into();
     if !matches!(kind, ItemType::Trait | ItemType::TraitAlias) {
-        span_bug!(cx.tcx.def_span(trait_ref.def_id), "`TraitRef` had unexpected kind {:?}", kind);
+        span_bug!(cx.tcx.def_span(trait_ref.def_id()), "`TraitRef` had unexpected kind {:?}", kind);
     }
-    inline::record_extern_fqn(cx, trait_ref.def_id, kind);
-    let path = external_path(cx, trait_ref.def_id, true, bindings, trait_ref.substs);
+    inline::record_extern_fqn(cx, trait_ref.def_id(), kind);
+    let path =
+        external_path(cx, trait_ref.def_id(), true, bindings, trait_ref.map_bound(|tr| tr.substs));
 
-    debug!("ty::TraitRef\n  subst: {:?}\n", trait_ref.substs);
+    debug!(?trait_ref);
 
     path
 }
@@ -187,7 +189,7 @@ fn clean_poly_trait_ref_with_bindings<'tcx>(
         })
         .collect();
 
-    let trait_ = clean_trait_ref_with_bindings(cx, poly_trait_ref.skip_binder(), bindings);
+    let trait_ = clean_trait_ref_with_bindings(cx, poly_trait_ref, bindings);
     GenericBound::TraitBound(
         PolyTrait { trait_, generic_params: late_bound_regions },
         hir::TraitBoundModifier::None,
@@ -212,19 +214,19 @@ fn clean_lifetime<'tcx>(lifetime: &hir::Lifetime, cx: &mut DocContext<'tcx>) ->
 pub(crate) fn clean_const<'tcx>(constant: &hir::ConstArg, cx: &mut DocContext<'tcx>) -> Constant {
     let def_id = cx.tcx.hir().body_owner_def_id(constant.value.body).to_def_id();
     Constant {
-        type_: clean_middle_ty(cx.tcx.type_of(def_id), cx, Some(def_id)),
+        type_: clean_middle_ty(ty::Binder::dummy(cx.tcx.type_of(def_id)), cx, Some(def_id)),
         kind: ConstantKind::Anonymous { body: constant.value.body },
     }
 }
 
 pub(crate) fn clean_middle_const<'tcx>(
-    constant: ty::Const<'tcx>,
+    constant: ty::Binder<'tcx, ty::Const<'tcx>>,
     cx: &mut DocContext<'tcx>,
 ) -> Constant {
     // FIXME: instead of storing the stringified expression, store `self` directly instead.
     Constant {
-        type_: clean_middle_ty(constant.ty(), cx, None),
-        kind: ConstantKind::TyConst { expr: constant.to_string().into() },
+        type_: clean_middle_ty(constant.map_bound(|c| c.ty()), cx, None),
+        kind: ConstantKind::TyConst { expr: constant.skip_binder().to_string().into() },
     }
 }
 
@@ -333,7 +335,7 @@ fn clean_poly_trait_predicate<'tcx>(
 
     let poly_trait_ref = pred.map_bound(|pred| pred.trait_ref);
     Some(WherePredicate::BoundPredicate {
-        ty: clean_middle_ty(poly_trait_ref.skip_binder().self_ty(), cx, None),
+        ty: clean_middle_ty(poly_trait_ref.self_ty(), cx, None),
         bounds: vec![clean_poly_trait_ref_with_bindings(cx, poly_trait_ref, ThinVec::new())],
         bound_params: Vec::new(),
     })
@@ -359,7 +361,7 @@ fn clean_type_outlives_predicate<'tcx>(
     let ty::OutlivesPredicate(ty, lt) = pred;
 
     Some(WherePredicate::BoundPredicate {
-        ty: clean_middle_ty(ty, cx, None),
+        ty: clean_middle_ty(ty::Binder::dummy(ty), cx, None),
         bounds: vec![GenericBound::Outlives(
             clean_middle_region(lt).expect("failed to clean lifetimes"),
         )],
@@ -367,10 +369,13 @@ fn clean_type_outlives_predicate<'tcx>(
     })
 }
 
-fn clean_middle_term<'tcx>(term: ty::Term<'tcx>, cx: &mut DocContext<'tcx>) -> Term {
-    match term.unpack() {
-        ty::TermKind::Ty(ty) => Term::Type(clean_middle_ty(ty, cx, None)),
-        ty::TermKind::Const(c) => Term::Constant(clean_middle_const(c, cx)),
+fn clean_middle_term<'tcx>(
+    term: ty::Binder<'tcx, ty::Term<'tcx>>,
+    cx: &mut DocContext<'tcx>,
+) -> Term {
+    match term.skip_binder().unpack() {
+        ty::TermKind::Ty(ty) => Term::Type(clean_middle_ty(term.rebind(ty), cx, None)),
+        ty::TermKind::Const(c) => Term::Constant(clean_middle_const(term.rebind(c), cx)),
     }
 }
 
@@ -379,7 +384,10 @@ fn clean_hir_term<'tcx>(term: &hir::Term<'tcx>, cx: &mut DocContext<'tcx>) -> Te
         hir::Term::Ty(ty) => Term::Type(clean_ty(ty, cx)),
         hir::Term::Const(c) => {
             let def_id = cx.tcx.hir().local_def_id(c.hir_id);
-            Term::Constant(clean_middle_const(ty::Const::from_anon_const(cx.tcx, def_id), cx))
+            Term::Constant(clean_middle_const(
+                ty::Binder::dummy(ty::Const::from_anon_const(cx.tcx, def_id)),
+                cx,
+            ))
         }
     }
 }
@@ -398,32 +406,31 @@ fn clean_projection_predicate<'tcx>(
         })
         .collect();
 
-    let ty::ProjectionPredicate { projection_ty, term } = pred.skip_binder();
-
     WherePredicate::EqPredicate {
-        lhs: Box::new(clean_projection(projection_ty, cx, None)),
-        rhs: Box::new(clean_middle_term(term, cx)),
+        lhs: Box::new(clean_projection(pred.map_bound(|p| p.projection_ty), cx, None)),
+        rhs: Box::new(clean_middle_term(pred.map_bound(|p| p.term), cx)),
         bound_params: late_bound_regions,
     }
 }
 
 fn clean_projection<'tcx>(
-    ty: ty::ProjectionTy<'tcx>,
+    ty: ty::Binder<'tcx, ty::AliasTy<'tcx>>,
     cx: &mut DocContext<'tcx>,
     def_id: Option<DefId>,
 ) -> Type {
-    if cx.tcx.def_kind(ty.item_def_id) == DefKind::ImplTraitPlaceholder {
+    if cx.tcx.def_kind(ty.skip_binder().def_id) == DefKind::ImplTraitPlaceholder {
         let bounds = cx
             .tcx
-            .explicit_item_bounds(ty.item_def_id)
+            .explicit_item_bounds(ty.skip_binder().def_id)
             .iter()
-            .map(|(bound, _)| EarlyBinder(*bound).subst(cx.tcx, ty.substs))
+            .map(|(bound, _)| EarlyBinder(*bound).subst(cx.tcx, ty.skip_binder().substs))
             .collect::<Vec<_>>();
         return clean_middle_opaque_bounds(cx, bounds);
     }
 
-    let trait_ = clean_trait_ref_with_bindings(cx, ty.trait_ref(cx.tcx), ThinVec::new());
-    let self_type = clean_middle_ty(ty.self_ty(), cx, None);
+    let trait_ =
+        clean_trait_ref_with_bindings(cx, ty.map_bound(|ty| ty.trait_ref(cx.tcx)), ThinVec::new());
+    let self_type = clean_middle_ty(ty.map_bound(|ty| ty.self_ty()), cx, None);
     let self_def_id = if let Some(def_id) = def_id {
         cx.tcx.opt_parent(def_id).or(Some(def_id))
     } else {
@@ -446,15 +453,16 @@ fn compute_should_show_cast(self_def_id: Option<DefId>, trait_: &Path, self_type
 }
 
 fn projection_to_path_segment<'tcx>(
-    ty: ty::ProjectionTy<'tcx>,
+    ty: ty::Binder<'tcx, ty::AliasTy<'tcx>>,
     cx: &mut DocContext<'tcx>,
 ) -> PathSegment {
-    let item = cx.tcx.associated_item(ty.item_def_id);
-    let generics = cx.tcx.generics_of(ty.item_def_id);
+    let item = cx.tcx.associated_item(ty.skip_binder().def_id);
+    let generics = cx.tcx.generics_of(ty.skip_binder().def_id);
     PathSegment {
         name: item.name,
         args: GenericArgs::AngleBracketed {
-            args: substs_to_args(cx, &ty.substs[generics.parent_count..], false).into(),
+            args: substs_to_args(cx, ty.map_bound(|ty| &ty.substs[generics.parent_count..]), false)
+                .into(),
             bindings: Default::default(),
         },
     }
@@ -470,7 +478,11 @@ fn clean_generic_param_def<'tcx>(
         }
         ty::GenericParamDefKind::Type { has_default, synthetic, .. } => {
             let default = if has_default {
-                Some(clean_middle_ty(cx.tcx.type_of(def.def_id), cx, Some(def.def_id)))
+                Some(clean_middle_ty(
+                    ty::Binder::dummy(cx.tcx.type_of(def.def_id)),
+                    cx,
+                    Some(def.def_id),
+                ))
             } else {
                 None
             };
@@ -488,9 +500,15 @@ fn clean_generic_param_def<'tcx>(
             def.name,
             GenericParamDefKind::Const {
                 did: def.def_id,
-                ty: Box::new(clean_middle_ty(cx.tcx.type_of(def.def_id), cx, Some(def.def_id))),
+                ty: Box::new(clean_middle_ty(
+                    ty::Binder::dummy(cx.tcx.type_of(def.def_id)),
+                    cx,
+                    Some(def.def_id),
+                )),
                 default: match has_default {
-                    true => Some(Box::new(cx.tcx.const_param_default(def.def_id).to_string())),
+                    true => Some(Box::new(
+                        cx.tcx.const_param_default(def.def_id).subst_identity().to_string(),
+                    )),
                     false => None,
                 },
             },
@@ -733,8 +751,10 @@ fn clean_ty_generics<'tcx>(
         .collect::<ThinVec<GenericParamDef>>();
 
     // param index -> [(trait DefId, associated type name & generics, type, higher-ranked params)]
-    let mut impl_trait_proj =
-        FxHashMap::<u32, Vec<(DefId, PathSegment, Ty<'_>, Vec<GenericParamDef>)>>::default();
+    let mut impl_trait_proj = FxHashMap::<
+        u32,
+        Vec<(DefId, PathSegment, ty::Binder<'_, Ty<'_>>, Vec<GenericParamDef>)>,
+    >::default();
 
     let where_predicates = preds
         .predicates
@@ -783,8 +803,8 @@ fn clean_ty_generics<'tcx>(
 
                     let proj = projection.map(|p| {
                         (
-                            clean_projection(p.skip_binder().projection_ty, cx, None),
-                            p.skip_binder().term,
+                            clean_projection(p.map_bound(|p| p.projection_ty), cx, None),
+                            p.map_bound(|p| p.term),
                         )
                     });
                     if let Some(((_, trait_did, name), rhs)) = proj
@@ -795,7 +815,7 @@ fn clean_ty_generics<'tcx>(
                         impl_trait_proj.entry(param_idx).or_default().push((
                             trait_did,
                             name,
-                            rhs.ty().unwrap(),
+                            rhs.map_bound(|rhs| rhs.ty().unwrap()),
                             p.get_bound_params()
                                 .into_iter()
                                 .flatten()
@@ -1066,7 +1086,7 @@ fn clean_fn_decl_from_did_and_sig<'tcx>(
 
     // We assume all empty tuples are default return type. This theoretically can discard `-> ()`,
     // but shouldn't change any code meaning.
-    let output = match clean_middle_ty(sig.skip_binder().output(), cx, None) {
+    let output = match clean_middle_ty(sig.output(), cx, None) {
         Type::Tuple(inner) if inner.is_empty() => DefaultReturn,
         ty => Return(ty),
     };
@@ -1076,11 +1096,10 @@ fn clean_fn_decl_from_did_and_sig<'tcx>(
         c_variadic: sig.skip_binder().c_variadic,
         inputs: Arguments {
             values: sig
-                .skip_binder()
                 .inputs()
                 .iter()
                 .map(|t| Argument {
-                    type_: clean_middle_ty(*t, cx, None),
+                    type_: clean_middle_ty(t.map_bound(|t| *t), cx, None),
                     name: names
                         .next()
                         .map(|i| i.name)
@@ -1134,7 +1153,8 @@ fn clean_trait_item<'tcx>(trait_item: &hir::TraitItem<'tcx>, cx: &mut DocContext
             hir::TraitItemKind::Type(bounds, Some(default)) => {
                 let generics = enter_impl_trait(cx, |cx| clean_generics(trait_item.generics, cx));
                 let bounds = bounds.iter().filter_map(|x| clean_generic_bound(x, cx)).collect();
-                let item_type = clean_middle_ty(hir_ty_to_ty(cx.tcx, default), cx, None);
+                let item_type =
+                    clean_middle_ty(ty::Binder::dummy(hir_ty_to_ty(cx.tcx, default)), cx, None);
                 AssocTypeItem(
                     Box::new(Typedef {
                         type_: clean_ty(default, cx),
@@ -1173,7 +1193,8 @@ pub(crate) fn clean_impl_item<'tcx>(
             hir::ImplItemKind::Type(hir_ty) => {
                 let type_ = clean_ty(hir_ty, cx);
                 let generics = clean_generics(impl_.generics, cx);
-                let item_type = clean_middle_ty(hir_ty_to_ty(cx.tcx, hir_ty), cx, None);
+                let item_type =
+                    clean_middle_ty(ty::Binder::dummy(hir_ty_to_ty(cx.tcx, hir_ty)), cx, None);
                 AssocTypeItem(
                     Box::new(Typedef { type_, generics, item_type: Some(item_type) }),
                     Vec::new(),
@@ -1192,7 +1213,11 @@ pub(crate) fn clean_middle_assoc_item<'tcx>(
     let tcx = cx.tcx;
     let kind = match assoc_item.kind {
         ty::AssocKind::Const => {
-            let ty = clean_middle_ty(tcx.type_of(assoc_item.def_id), cx, Some(assoc_item.def_id));
+            let ty = clean_middle_ty(
+                ty::Binder::dummy(tcx.type_of(assoc_item.def_id)),
+                cx,
+                Some(assoc_item.def_id),
+            );
 
             let provided = match assoc_item.container {
                 ty::ImplContainer => true,
@@ -1375,7 +1400,7 @@ pub(crate) fn clean_middle_assoc_item<'tcx>(
                     AssocTypeItem(
                         Box::new(Typedef {
                             type_: clean_middle_ty(
-                                tcx.type_of(assoc_item.def_id),
+                                ty::Binder::dummy(tcx.type_of(assoc_item.def_id)),
                                 cx,
                                 Some(assoc_item.def_id),
                             ),
@@ -1393,7 +1418,7 @@ pub(crate) fn clean_middle_assoc_item<'tcx>(
                 AssocTypeItem(
                     Box::new(Typedef {
                         type_: clean_middle_ty(
-                            tcx.type_of(assoc_item.def_id),
+                            ty::Binder::dummy(tcx.type_of(assoc_item.def_id)),
                             cx,
                             Some(assoc_item.def_id),
                         ),
@@ -1437,8 +1462,11 @@ fn clean_qpath<'tcx>(hir_ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> Type
         hir::QPath::Resolved(Some(qself), p) => {
             // Try to normalize `<X as Y>::T` to a type
             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
-            if let Some(normalized_value) = normalize(cx, ty) {
-                return clean_middle_ty(normalized_value, cx, None);
+            // `hir_to_ty` can return projection types with escaping vars for GATs, e.g. `<() as Trait>::Gat<'_>`
+            if !ty.has_escaping_bound_vars() {
+                if let Some(normalized_value) = normalize(cx, ty::Binder::dummy(ty)) {
+                    return clean_middle_ty(normalized_value, cx, None);
+                }
             }
 
             let trait_segments = &p.segments[..p.segments.len() - 1];
@@ -1461,11 +1489,13 @@ fn clean_qpath<'tcx>(hir_ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> Type
         hir::QPath::TypeRelative(qself, segment) => {
             let ty = hir_ty_to_ty(cx.tcx, hir_ty);
             let res = match ty.kind() {
-                ty::Projection(proj) => Res::Def(DefKind::Trait, proj.trait_ref(cx.tcx).def_id),
+                ty::Alias(ty::Projection, proj) => {
+                    Res::Def(DefKind::Trait, proj.trait_ref(cx.tcx).def_id)
+                }
                 // Rustdoc handles `ty::Error`s by turning them into `Type::Infer`s.
                 ty::Error(_) => return Type::Infer,
                 // Otherwise, this is an inherent associated type.
-                _ => return clean_middle_ty(ty, cx, None),
+                _ => return clean_middle_ty(ty::Binder::dummy(ty), cx, None),
             };
             let trait_ = clean_path(&hir::Path { span, res, segments: &[] }, cx);
             register_res(cx, trait_.res);
@@ -1584,7 +1614,7 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T
     match ty.kind {
         TyKind::Never => Primitive(PrimitiveType::Never),
         TyKind::Ptr(ref m) => RawPointer(m.mutbl, Box::new(clean_ty(m.ty, cx))),
-        TyKind::Rptr(ref l, ref m) => {
+        TyKind::Ref(ref l, ref m) => {
             let lifetime = if l.is_anonymous() { None } else { Some(clean_lifetime(*l, cx)) };
             BorrowedRef { lifetime, mutability: m.mutbl, type_: Box::new(clean_ty(m.ty, cx)) }
         }
@@ -1632,7 +1662,10 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T
 }
 
 /// Returns `None` if the type could not be normalized
-fn normalize<'tcx>(cx: &mut DocContext<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>> {
+fn normalize<'tcx>(
+    cx: &mut DocContext<'tcx>,
+    ty: ty::Binder<'tcx, Ty<'tcx>>,
+) -> Option<ty::Binder<'tcx, Ty<'tcx>>> {
     // HACK: low-churn fix for #79459 while we wait for a trait normalization fix
     if !cx.tcx.sess.opts.unstable_opts.normalize_docs {
         return None;
@@ -1660,14 +1693,14 @@ fn normalize<'tcx>(cx: &mut DocContext<'tcx>, ty: Ty<'tcx>) -> Option<Ty<'tcx>>
     }
 }
 
+#[instrument(level = "trace", skip(cx), ret)]
 pub(crate) fn clean_middle_ty<'tcx>(
-    ty: Ty<'tcx>,
+    bound_ty: ty::Binder<'tcx, Ty<'tcx>>,
     cx: &mut DocContext<'tcx>,
     def_id: Option<DefId>,
 ) -> Type {
-    trace!("cleaning type: {:?}", ty);
-    let ty = normalize(cx, ty).unwrap_or(ty);
-    match *ty.kind() {
+    let bound_ty = normalize(cx, bound_ty).unwrap_or(bound_ty);
+    match *bound_ty.skip_binder().kind() {
         ty::Never => Primitive(PrimitiveType::Never),
         ty::Bool => Primitive(PrimitiveType::Bool),
         ty::Char => Primitive(PrimitiveType::Char),
@@ -1675,20 +1708,23 @@ pub(crate) fn clean_middle_ty<'tcx>(
         ty::Uint(uint_ty) => Primitive(uint_ty.into()),
         ty::Float(float_ty) => Primitive(float_ty.into()),
         ty::Str => Primitive(PrimitiveType::Str),
-        ty::Slice(ty) => Slice(Box::new(clean_middle_ty(ty, cx, None))),
+        ty::Slice(ty) => Slice(Box::new(clean_middle_ty(bound_ty.rebind(ty), cx, None))),
         ty::Array(ty, mut n) => {
             n = n.eval(cx.tcx, ty::ParamEnv::reveal_all());
             let n = print_const(cx, n);
-            Array(Box::new(clean_middle_ty(ty, cx, None)), n.into())
+            Array(Box::new(clean_middle_ty(bound_ty.rebind(ty), cx, None)), n.into())
+        }
+        ty::RawPtr(mt) => {
+            RawPointer(mt.mutbl, Box::new(clean_middle_ty(bound_ty.rebind(mt.ty), cx, None)))
         }
-        ty::RawPtr(mt) => RawPointer(mt.mutbl, Box::new(clean_middle_ty(mt.ty, cx, None))),
         ty::Ref(r, ty, mutbl) => BorrowedRef {
             lifetime: clean_middle_region(r),
             mutability: mutbl,
-            type_: Box::new(clean_middle_ty(ty, cx, None)),
+            type_: Box::new(clean_middle_ty(bound_ty.rebind(ty), cx, None)),
         },
         ty::FnDef(..) | ty::FnPtr(_) => {
-            let sig = ty.fn_sig(cx.tcx);
+            // FIXME: should we merge the outer and inner binders somehow?
+            let sig = bound_ty.skip_binder().fn_sig(cx.tcx);
             let decl = clean_fn_decl_from_did_and_sig(cx, None, sig);
             BareFunction(Box::new(BareFunctionDecl {
                 unsafety: sig.unsafety(),
@@ -1705,12 +1741,18 @@ pub(crate) fn clean_middle_ty<'tcx>(
                 AdtKind::Enum => ItemType::Enum,
             };
             inline::record_extern_fqn(cx, did, kind);
-            let path = external_path(cx, did, false, ThinVec::new(), substs);
+            let path = external_path(cx, did, false, ThinVec::new(), bound_ty.rebind(substs));
             Type::Path { path }
         }
         ty::Foreign(did) => {
             inline::record_extern_fqn(cx, did, ItemType::ForeignType);
-            let path = external_path(cx, did, false, ThinVec::new(), InternalSubsts::empty());
+            let path = external_path(
+                cx,
+                did,
+                false,
+                ThinVec::new(),
+                ty::Binder::dummy(InternalSubsts::empty()),
+            );
             Type::Path { path }
         }
         ty::Dynamic(obj, ref reg, _) => {
@@ -1721,11 +1763,11 @@ pub(crate) fn clean_middle_ty<'tcx>(
             let did = obj
                 .principal_def_id()
                 .or_else(|| dids.next())
-                .unwrap_or_else(|| panic!("found trait object `{:?}` with no traits?", ty));
+                .unwrap_or_else(|| panic!("found trait object `{bound_ty:?}` with no traits?"));
             let substs = match obj.principal() {
-                Some(principal) => principal.skip_binder().substs,
+                Some(principal) => principal.map_bound(|p| p.substs),
                 // marker traits have no substs.
-                _ => cx.tcx.intern_substs(&[]),
+                _ => ty::Binder::dummy(InternalSubsts::empty()),
             };
 
             inline::record_extern_fqn(cx, did, ItemType::Trait);
@@ -1736,7 +1778,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
             let lifetime = clean_middle_region(*reg);
             let mut bounds = dids
                 .map(|did| {
-                    let empty = cx.tcx.intern_substs(&[]);
+                    let empty = ty::Binder::dummy(InternalSubsts::empty());
                     let path = external_path(cx, did, false, ThinVec::new(), empty);
                     inline::record_extern_fqn(cx, did, ItemType::Trait);
                     PolyTrait { trait_: path, generic_params: Vec::new() }
@@ -1747,15 +1789,17 @@ pub(crate) fn clean_middle_ty<'tcx>(
                 .projection_bounds()
                 .map(|pb| TypeBinding {
                     assoc: projection_to_path_segment(
-                        pb.skip_binder()
-                            // HACK(compiler-errors): Doesn't actually matter what self
-                            // type we put here, because we're only using the GAT's substs.
-                            .with_self_ty(cx.tcx, cx.tcx.types.self_param)
-                            .projection_ty,
+                        pb.map_bound(|pb| {
+                            pb
+                                // HACK(compiler-errors): Doesn't actually matter what self
+                                // type we put here, because we're only using the GAT's substs.
+                                .with_self_ty(cx.tcx, cx.tcx.types.self_param)
+                                .projection_ty
+                        }),
                         cx,
                     ),
                     kind: TypeBindingKind::Equality {
-                        term: clean_middle_term(pb.skip_binder().term, cx),
+                        term: clean_middle_term(pb.map_bound(|pb| pb.term), cx),
                     },
                 })
                 .collect();
@@ -1779,9 +1823,11 @@ pub(crate) fn clean_middle_ty<'tcx>(
 
             DynTrait(bounds, lifetime)
         }
-        ty::Tuple(t) => Tuple(t.iter().map(|t| clean_middle_ty(t, cx, None)).collect()),
+        ty::Tuple(t) => {
+            Tuple(t.iter().map(|t| clean_middle_ty(bound_ty.rebind(t), cx, None)).collect())
+        }
 
-        ty::Projection(ref data) => clean_projection(*data, cx, def_id),
+        ty::Alias(ty::Projection, ref data) => clean_projection(bound_ty.rebind(*data), cx, def_id),
 
         ty::Param(ref p) => {
             if let Some(bounds) = cx.impl_trait_bounds.remove(&p.index.into()) {
@@ -1791,7 +1837,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
             }
         }
 
-        ty::Opaque(def_id, substs) => {
+        ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
             // Grab the "TraitA + TraitB" from `impl TraitA + TraitB`,
             // by looking up the bounds associated with the def_id.
             let bounds = cx
@@ -1809,7 +1855,7 @@ pub(crate) fn clean_middle_ty<'tcx>(
         ty::Placeholder(..) => panic!("Placeholder"),
         ty::GeneratorWitness(..) => panic!("GeneratorWitness"),
         ty::Infer(..) => panic!("Infer"),
-        ty::Error(_) => panic!("Error"),
+        ty::Error(_) => rustc_errors::FatalError.raise(),
     }
 }
 
@@ -1854,9 +1900,12 @@ fn clean_middle_opaque_bounds<'tcx>(
                     {
                         if proj.projection_ty.trait_ref(cx.tcx) == trait_ref.skip_binder() {
                             Some(TypeBinding {
-                                assoc: projection_to_path_segment(proj.projection_ty, cx),
+                                assoc: projection_to_path_segment(
+                                    bound.kind().rebind(proj.projection_ty),
+                                    cx,
+                                ),
                                 kind: TypeBindingKind::Equality {
-                                    term: clean_middle_term(proj.term, cx),
+                                    term: clean_middle_term(bound.kind().rebind(proj.term), cx),
                                 },
                             })
                         } else {
@@ -1887,7 +1936,7 @@ pub(crate) fn clean_middle_field<'tcx>(field: &ty::FieldDef, cx: &mut DocContext
     clean_field_with_def_id(
         field.did,
         field.name,
-        clean_middle_ty(cx.tcx.type_of(field.did), cx, Some(field.did)),
+        clean_middle_ty(ty::Binder::dummy(cx.tcx.type_of(field.did)), cx, Some(field.did)),
         cx,
     )
 }
@@ -1902,20 +1951,27 @@ pub(crate) fn clean_field_with_def_id(
 }
 
 pub(crate) fn clean_variant_def<'tcx>(variant: &ty::VariantDef, cx: &mut DocContext<'tcx>) -> Item {
+    let discriminant = match variant.discr {
+        ty::VariantDiscr::Explicit(def_id) => Some(Discriminant { expr: None, value: def_id }),
+        ty::VariantDiscr::Relative(_) => None,
+    };
+
     let kind = match variant.ctor_kind() {
-        Some(CtorKind::Const) => Variant::CLike(match variant.discr {
-            ty::VariantDiscr::Explicit(def_id) => Some(Discriminant { expr: None, value: def_id }),
-            ty::VariantDiscr::Relative(_) => None,
-        }),
-        Some(CtorKind::Fn) => Variant::Tuple(
+        Some(CtorKind::Const) => VariantKind::CLike,
+        Some(CtorKind::Fn) => VariantKind::Tuple(
             variant.fields.iter().map(|field| clean_middle_field(field, cx)).collect(),
         ),
-        None => Variant::Struct(VariantStruct {
-            ctor_kind: None,
+        None => VariantKind::Struct(VariantStruct {
             fields: variant.fields.iter().map(|field| clean_middle_field(field, cx)).collect(),
         }),
     };
-    Item::from_def_id_and_parts(variant.def_id, Some(variant.name), VariantItem(kind), cx)
+
+    Item::from_def_id_and_parts(
+        variant.def_id,
+        Some(variant.name),
+        VariantItem(Variant { kind, discriminant }),
+        cx,
+    )
 }
 
 fn clean_variant_data<'tcx>(
@@ -1923,19 +1979,22 @@ fn clean_variant_data<'tcx>(
     disr_expr: &Option<hir::AnonConst>,
     cx: &mut DocContext<'tcx>,
 ) -> Variant {
-    match variant {
-        hir::VariantData::Struct(..) => Variant::Struct(VariantStruct {
-            ctor_kind: None,
+    let discriminant = disr_expr.map(|disr| Discriminant {
+        expr: Some(disr.body),
+        value: cx.tcx.hir().local_def_id(disr.hir_id).to_def_id(),
+    });
+
+    let kind = match variant {
+        hir::VariantData::Struct(..) => VariantKind::Struct(VariantStruct {
             fields: variant.fields().iter().map(|x| clean_field(x, cx)).collect(),
         }),
         hir::VariantData::Tuple(..) => {
-            Variant::Tuple(variant.fields().iter().map(|x| clean_field(x, cx)).collect())
+            VariantKind::Tuple(variant.fields().iter().map(|x| clean_field(x, cx)).collect())
         }
-        hir::VariantData::Unit(..) => Variant::CLike(disr_expr.map(|disr| Discriminant {
-            expr: Some(disr.body),
-            value: cx.tcx.hir().local_def_id(disr.hir_id).to_def_id(),
-        })),
-    }
+        hir::VariantData::Unit(..) => VariantKind::CLike,
+    };
+
+    Variant { discriminant, kind }
 }
 
 fn clean_path<'tcx>(path: &hir::Path<'tcx>, cx: &mut DocContext<'tcx>) -> Path {
@@ -2052,10 +2111,12 @@ fn get_all_import_attributes<'hir>(
 ) {
     let hir_map = tcx.hir();
     let mut visitor = OneLevelVisitor::new(hir_map, target_hir_id);
+    let mut visited = FxHashSet::default();
     // If the item is an import and has at least a path with two parts, we go into it.
     while let hir::ItemKind::Use(path, _) = item.kind &&
         path.segments.len() > 1 &&
-        let hir::def::Res::Def(_, def_id) = path.segments[path.segments.len() - 2].res
+        let hir::def::Res::Def(_, def_id) = path.segments[path.segments.len() - 2].res &&
+        visited.insert(def_id)
     {
         if let Some(hir::Node::Item(parent_item)) = hir_map.get_if_local(def_id) {
             // We add the attributes from this import into the list.
@@ -2100,7 +2161,7 @@ fn clean_maybe_renamed_item<'tcx>(
             }),
             ItemKind::TyAlias(hir_ty, generics) => {
                 let rustdoc_ty = clean_ty(hir_ty, cx);
-                let ty = clean_middle_ty(hir_ty_to_ty(cx.tcx, hir_ty), cx, None);
+                let ty = clean_middle_ty(ty::Binder::dummy(hir_ty_to_ty(cx.tcx, hir_ty)), cx, None);
                 TypedefItem(Box::new(Typedef {
                     type_: rustdoc_ty,
                     generics: clean_generics(generics, cx),
@@ -2211,7 +2272,9 @@ fn clean_impl<'tcx>(
 
     let for_ = clean_ty(impl_.self_ty, cx);
     let type_alias = for_.def_id(&cx.cache).and_then(|did| match tcx.def_kind(did) {
-        DefKind::TyAlias => Some(clean_middle_ty(tcx.type_of(did), cx, Some(did))),
+        DefKind::TyAlias => {
+            Some(clean_middle_ty(ty::Binder::dummy(tcx.type_of(did)), cx, Some(did)))
+        }
         _ => None,
     });
     let mut make_item = |trait_: Option<Path>, for_: Type, items: Vec<Item>| {
@@ -2380,7 +2443,8 @@ fn clean_use_statement_inner<'tcx>(
     let inner = if kind == hir::UseKind::Glob {
         if !denied {
             let mut visited = FxHashSet::default();
-            if let Some(items) = inline::try_inline_glob(cx, path.res, &mut visited, inlined_names)
+            if let Some(items) =
+                inline::try_inline_glob(cx, path.res, current_mod, &mut visited, inlined_names)
             {
                 return items;
             }