diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 47b006985ec..db8a6d96204 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -558,7 +558,7 @@ impl<'me, 'tcx> BoundVarReplacer<'me, 'tcx> {
     fn universe_for(&mut self, debruijn: ty::DebruijnIndex) -> ty::UniverseIndex {
         let infcx = self.infcx;
         let index =
-            self.universe_indices.len() - debruijn.as_usize() + self.current_index.as_usize() - 1;
+            self.universe_indices.len() + self.current_index.as_usize() - debruijn.as_usize() - 1;
         let universe = self.universe_indices[index].unwrap_or_else(|| {
             for i in self.universe_indices.iter_mut().take(index + 1) {
                 *i = i.or_else(|| Some(infcx.create_next_universe()))