diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index c3f56ae2756..af30d9121d1 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -898,7 +898,10 @@ fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
                 if debruijn.as_usize() + 1
                     > self.current_index.as_usize() + self.universe_indices.len() =>
             {
-                bug!("Bound vars outside of `self.universe_indices`");
+                bug!(
+                    "Bound vars {r:#?} outside of `self.universe_indices`: {:#?}",
+                    self.universe_indices
+                );
             }
             ty::ReLateBound(debruijn, br) if debruijn >= self.current_index => {
                 let universe = self.universe_for(debruijn);
@@ -916,7 +919,10 @@ fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
                 if debruijn.as_usize() + 1
                     > self.current_index.as_usize() + self.universe_indices.len() =>
             {
-                bug!("Bound vars outside of `self.universe_indices`");
+                bug!(
+                    "Bound vars {t:#?} outside of `self.universe_indices`: {:#?}",
+                    self.universe_indices
+                );
             }
             ty::Bound(debruijn, bound_ty) if debruijn >= self.current_index => {
                 let universe = self.universe_for(debruijn);
@@ -935,7 +941,10 @@ fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> {
                 if debruijn.as_usize() + 1
                     > self.current_index.as_usize() + self.universe_indices.len() =>
             {
-                bug!("Bound vars outside of `self.universe_indices`");
+                bug!(
+                    "Bound vars {ct:#?} outside of `self.universe_indices`: {:#?}",
+                    self.universe_indices
+                );
             }
             ty::ConstKind::Bound(debruijn, bound_const) if debruijn >= self.current_index => {
                 let universe = self.universe_for(debruijn);