2 files changed, 10 insertions, 5 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
index 81c72fc4b7b..fbf96833187 100644
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -524,13 +524,15 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                             if let Entry::Occupied(v) = vid_map.entry(*smaller) {
                                 let smaller_deps = v.into_mut();
                                 smaller_deps.larger.insert(*larger);
-                                smaller_deps.larger.remove(&target);
+                                // FIXME(#120456) - is `swap_remove` correct?
+                                smaller_deps.larger.swap_remove(&target);
                             }
 
                             if let Entry::Occupied(v) = vid_map.entry(*larger) {
                                 let larger_deps = v.into_mut();
                                 larger_deps.smaller.insert(*smaller);
-                                larger_deps.smaller.remove(&target);
+                                // FIXME(#120456) - is `swap_remove` correct?
+                                larger_deps.smaller.swap_remove(&target);
                             }
                         }
                         (&RegionTarget::RegionVid(v1), &RegionTarget::Region(r1)) => {
@@ -543,13 +545,15 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                             if let Entry::Occupied(v) = vid_map.entry(*smaller) {
                                 let smaller_deps = v.into_mut();
                                 smaller_deps.larger.insert(*larger);
-                                smaller_deps.larger.remove(&target);
+                                // FIXME(#120456) - is `swap_remove` correct?
+                                smaller_deps.larger.swap_remove(&target);
                             }
 
                             if let Entry::Occupied(v) = vid_map.entry(*larger) {
                                 let larger_deps = v.into_mut();
                                 larger_deps.smaller.insert(*smaller);
-                                larger_deps.smaller.remove(&target);
+                                // FIXME(#120456) - is `swap_remove` correct?
+                                larger_deps.smaller.swap_remove(&target);
                             }
                         }
                     }
diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
index 73df1be6b55..e1a49ecf1b6 100644
--- a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs
@@ -522,7 +522,8 @@ pub(crate) fn to_pretty_impl_header(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Opti
     for (p, _) in predicates {
         if let Some(poly_trait_ref) = p.as_trait_clause() {
             if Some(poly_trait_ref.def_id()) == sized_trait {
-                types_without_default_bounds.remove(&poly_trait_ref.self_ty().skip_binder());
+                // FIXME(#120456) - is `swap_remove` correct?
+                types_without_default_bounds.swap_remove(&poly_trait_ref.self_ty().skip_binder());
                 continue;
             }
         }