Remove unused part of return value from `replace_bound_vars_with_placeholders`

3 files changed, 6 insertions, 6 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 71e34d2dcd0..f23d3bb7611 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -167,7 +167,7 @@ pub(super) fn poly_project_and_unify_type<'cx, 'tcx>(
 
     let infcx = selcx.infcx();
     infcx.commit_if_ok(|_snapshot| {
-        let (placeholder_predicate, _) =
+        let placeholder_predicate =
             infcx.replace_bound_vars_with_placeholders(&obligation.predicate);
 
         let placeholder_obligation = obligation.with(placeholder_predicate);
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 625bb5d7a44..76be4a80452 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -253,7 +253,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             let trait_obligations: Vec<PredicateObligation<'_>> =
                 self.infcx.commit_unconditionally(|_| {
                     let poly_trait_ref = obligation.predicate.to_poly_trait_ref();
-                    let (trait_ref, _) =
+                    let trait_ref =
                         self.infcx.replace_bound_vars_with_placeholders(&poly_trait_ref);
                     let cause = obligation.derived_cause(ImplDerivedObligation);
                     self.impl_or_trait_obligations(
@@ -437,7 +437,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         debug!("confirm_trait_alias_candidate({:?}, {:?})", obligation, alias_def_id);
 
         self.infcx.commit_unconditionally(|_| {
-            let (predicate, _) =
+            let predicate =
                 self.infcx().replace_bound_vars_with_placeholders(&obligation.predicate);
             let trait_ref = predicate.trait_ref;
             let trait_def_id = trait_ref.def_id;
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 2d6ccfe031e..ab4226c4ed6 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1161,7 +1161,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         obligation: &TraitObligation<'tcx>,
     ) -> Option<ty::PolyTraitRef<'tcx>> {
         let poly_trait_predicate = self.infcx().resolve_vars_if_possible(&obligation.predicate);
-        let (placeholder_trait_predicate, _) =
+        let placeholder_trait_predicate =
             self.infcx().replace_bound_vars_with_placeholders(&poly_trait_predicate);
         debug!(
             "match_projection_obligation_against_definition_bounds: \
@@ -1640,7 +1640,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 let ty: ty::Binder<Ty<'tcx>> = ty::Binder::bind(ty); // <----/
 
                 self.infcx.commit_unconditionally(|_| {
-                    let (placeholder_ty, _) = self.infcx.replace_bound_vars_with_placeholders(&ty);
+                    let placeholder_ty = self.infcx.replace_bound_vars_with_placeholders(&ty);
                     let Normalized { value: normalized_ty, mut obligations } =
                         ensure_sufficient_stack(|| {
                             project::normalize_with_depth(
@@ -1708,7 +1708,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             return Err(());
         }
 
-        let (placeholder_obligation, _) =
+        let placeholder_obligation =
             self.infcx().replace_bound_vars_with_placeholders(&obligation.predicate);
         let placeholder_obligation_trait_ref = placeholder_obligation.trait_ref;