diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs
index b583705ac43..9da464f283e 100644
--- a/compiler/rustc_trait_selection/src/solve/project_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs
@@ -296,7 +296,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
         goal: Goal<'tcx, Self>,
         assumption: ty::Predicate<'tcx>,
     ) -> QueryResult<'tcx> {
-        if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred() {
+        if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred()
+            && poly_projection_pred.projection_def_id() == goal.predicate.def_id()
+        {
             ecx.infcx.probe(|_| {
                 let assumption_projection_pred =
                     ecx.infcx.instantiate_bound_vars_with_infer(poly_projection_pred);
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index d74857dc4b4..45b6a5f4ec5 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -65,7 +65,9 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
         goal: Goal<'tcx, Self>,
         assumption: ty::Predicate<'tcx>,
     ) -> QueryResult<'tcx> {
-        if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred() {
+        if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred()
+            && poly_trait_pred.def_id() == goal.predicate.def_id()
+        {
             // FIXME: Constness and polarity
             ecx.infcx.probe(|_| {
                 let assumption_trait_pred =