change map_bound(|_| x to rebind(x

Author: fee1-dead

compiler/rustc_middle/src/ty/mod.rs

@@ -580,7 +580,7 @@ impl<'tcx> Predicate<'tcx> {
         if let PredicateKind::Trait(TraitPredicate { trait_ref, constness, polarity }) = self.kind().skip_binder()
             && constness != BoundConstness::NotConst
         {
-            self = tcx.mk_predicate(self.kind().map_bound(|_| PredicateKind::Trait(TraitPredicate {
+            self = tcx.mk_predicate(self.kind().rebind(PredicateKind::Trait(TraitPredicate {
                 trait_ref,
                 constness: BoundConstness::NotConst,
                 polarity,

compiler/rustc_trait_selection/src/traits/relationships.rs

@@ -31,14 +31,14 @@ pub(crate) fn update<'tcx, T>(
             obligation
                 .predicate
                 .kind()
-                .map_bound(|_| {
+                .rebind(
                     // (*) binder moved here
                     ty::PredicateKind::Trait(ty::TraitPredicate {
                         trait_ref,
                         constness: tpred.constness,
                         polarity: tpred.polarity,
                     })
-                })
+                )
                 .to_predicate(infcx.tcx),
         );
         // Don't report overflow errors. Otherwise equivalent to may_hold.

compiler/rustc_typeck/src/check/closure.rs

@@ -182,9 +182,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         ty::PredicateKind::Projection(proj_predicate) => self
                             .deduce_sig_from_projection(
                                 Some(span.0),
-                                pred.0.kind().rebind(
-                                    pred.map_bound(|_| proj_predicate).subst(self.tcx, substs),
-                                ),
+                                pred.0
+                                    .kind()
+                                    .rebind(pred.rebind(proj_predicate).subst(self.tcx, substs)),
                             ),
                         _ => None,
                     });