Only elaborate principal in object_region_bounds

Author: compiler-errors

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs

@@ -204,7 +204,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         for def_ids in associated_types.values_mut() {
             for (projection_bound, span) in &projection_bounds {
                 let def_id = projection_bound.projection_def_id();
-                // FIXME(#120456) - is `swap_remove` correct?
                 def_ids.swap_remove(&def_id);
                 if tcx.generics_require_sized_self(def_id) {
                     tcx.emit_node_span_lint(

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -970,10 +970,10 @@ pub fn object_region_bounds<'tcx>(
     existential_predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
 ) -> Vec<ty::Region<'tcx>> {
     let predicates = existential_predicates.iter().filter_map(|predicate| {
-        if let ty::ExistentialPredicate::Projection(_) = predicate.skip_binder() {
-            None
-        } else {
+        if let ty::ExistentialPredicate::Trait(_) = predicate.skip_binder() {
             Some(predicate.with_self_ty(tcx, tcx.types.trait_object_dummy_self))
+        } else {
+            None
         }
     });