1 files changed, 23 insertions, 11 deletions
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 0182d50773d..8ad1ed09597 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -167,8 +167,7 @@ fn clean_generic_bound<'tcx>(
             let trait_ref = ty::Binder::dummy(ty::TraitRef::identity(cx.tcx, def_id));
 
             let generic_args = clean_generic_args(generic_args, cx);
-            let GenericArgs::AngleBracketed { bindings, .. } = generic_args
-            else {
+            let GenericArgs::AngleBracketed { bindings, .. } = generic_args else {
                 bug!("clean: parenthesized `GenericBound::LangItemTrait`");
             };
 
@@ -1818,33 +1817,46 @@ fn can_elide_trait_object_lifetime_bound<'tcx>(
 #[derive(Debug)]
 pub(crate) enum ContainerTy<'tcx> {
     Ref(ty::Region<'tcx>),
-    Regular { ty: DefId, substs: ty::Binder<'tcx, &'tcx [ty::GenericArg<'tcx>]>, arg: usize },
+    Regular {
+        ty: DefId,
+        args: ty::Binder<'tcx, &'tcx [ty::GenericArg<'tcx>]>,
+        has_self: bool,
+        arg: usize,
+    },
 }
 
 impl<'tcx> ContainerTy<'tcx> {
     fn object_lifetime_default(self, tcx: TyCtxt<'tcx>) -> ObjectLifetimeDefault<'tcx> {
         match self {
             Self::Ref(region) => ObjectLifetimeDefault::Arg(region),
-            Self::Regular { ty: container, substs, arg: index } => {
+            Self::Regular { ty: container, args, has_self, arg: index } => {
                 let (DefKind::Struct
                 | DefKind::Union
                 | DefKind::Enum
-                | DefKind::TyAlias
-                | DefKind::Trait
-                | DefKind::AssocTy
-                | DefKind::Variant) = tcx.def_kind(container)
+                | DefKind::TyAlias { .. }
+                | DefKind::Trait) = tcx.def_kind(container)
                 else {
                     return ObjectLifetimeDefault::Empty;
                 };
 
                 let generics = tcx.generics_of(container);
-                let param = generics.params[index].def_id;
-                let default = tcx.object_lifetime_default(param);
+                debug_assert_eq!(generics.parent_count, 0);
+
+                // If the container is a trait object type, the arguments won't contain the self type but the
+                // generics of the corresponding trait will. In such a case, offset the index by one.
+                // For comparison, if the container is a trait inside a bound, the arguments do contain the
+                // self type.
+                let offset =
+                    if !has_self && generics.parent.is_none() && generics.has_self { 1 } else { 0 };
+                let param = generics.params[index + offset].def_id;
 
+                let default = tcx.object_lifetime_default(param);
                 match default {
                     rbv::ObjectLifetimeDefault::Param(lifetime) => {
+                        // The index is relative to the parent generics but since we don't have any,
+                        // we don't need to translate it.
                         let index = generics.param_def_id_to_index[&lifetime];
-                        let arg = substs.skip_binder()[index as usize].expect_region();
+                        let arg = args.skip_binder()[index as usize].expect_region();
                         ObjectLifetimeDefault::Arg(arg)
                     }
                     rbv::ObjectLifetimeDefault::Empty => ObjectLifetimeDefault::Empty,