Rollup merge of #107780 - compiler-errors:instantiate-binder, r=lcnr

Rename `replace_bound_vars_with_*` to `instantiate_binder_with_*`

Mentioning "binder" rather than "bound vars", imo, makes it clearer that we're doing something to the binder as a whole.

Also, "instantiate" is the verb that I'm always reaching for when I'm looking for these functions, and the name that we use in the new solver anyways.

r? types

28 files changed, 67 insertions, 60 deletions

diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index a75ec87be4c..3006e27e1d5 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -1139,7 +1139,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         if let ty::Adt(def, substs) = ty.kind()
                             && Some(def.did()) == tcx.lang_items().pin_type()
                             && let ty::Ref(_, _, hir::Mutability::Mut) = substs.type_at(0).kind()
-                            && let self_ty = infcx.replace_bound_vars_with_fresh_vars(
+                            && let self_ty = infcx.instantiate_binder_with_fresh_vars(
                                 fn_call_span,
                                 LateBoundRegionConversionTime::FnCall,
                                 tcx.fn_sig(method_did).subst(tcx, method_substs).input(0),
diff --git a/compiler/rustc_borrowck/src/type_check/input_output.rs b/compiler/rustc_borrowck/src/type_check/input_output.rs
index fa9ea769a14..c6b78df9a5f 100644
--- a/compiler/rustc_borrowck/src/type_check/input_output.rs
+++ b/compiler/rustc_borrowck/src/type_check/input_output.rs
@@ -38,7 +38,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         // so that they represent the view from "inside" the closure.
         let user_provided_sig = self
             .instantiate_canonical_with_fresh_inference_vars(body.span, &user_provided_poly_sig);
-        let user_provided_sig = self.infcx.replace_bound_vars_with_fresh_vars(
+        let user_provided_sig = self.infcx.instantiate_binder_with_fresh_vars(
             body.span,
             LateBoundRegionConversionTime::FnCall,
             user_provided_sig,
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
index 21e70041810..236e36f28ca 100644
--- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
+++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
@@ -246,7 +246,7 @@ fn compare_method_predicate_entailment<'tcx>(
 
     let mut wf_tys = FxIndexSet::default();
 
-    let unnormalized_impl_sig = infcx.replace_bound_vars_with_fresh_vars(
+    let unnormalized_impl_sig = infcx.instantiate_binder_with_fresh_vars(
         impl_m_span,
         infer::HigherRankedType,
         tcx.fn_sig(impl_m.def_id).subst_identity(),
@@ -640,7 +640,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
     let impl_sig = ocx.normalize(
         &norm_cause,
         param_env,
-        infcx.replace_bound_vars_with_fresh_vars(
+        infcx.instantiate_binder_with_fresh_vars(
             return_span,
             infer::HigherRankedType,
             tcx.fn_sig(impl_m.def_id).subst_identity(),
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
index c220956a201..089863a66e7 100644
--- a/compiler/rustc_hir_typeck/src/callee.rs
+++ b/compiler/rustc_hir_typeck/src/callee.rs
@@ -156,7 +156,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // fnmut vs fnonce. If so, we have to defer further processing.
                 if self.closure_kind(substs).is_none() {
                     let closure_sig = substs.as_closure().sig();
-                    let closure_sig = self.replace_bound_vars_with_fresh_vars(
+                    let closure_sig = self.instantiate_binder_with_fresh_vars(
                         call_expr.span,
                         infer::FnCall,
                         closure_sig,
@@ -437,7 +437,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // renormalize the associated types at this point, since they
         // previously appeared within a `Binder<>` and hence would not
         // have been normalized before.
-        let fn_sig = self.replace_bound_vars_with_fresh_vars(call_expr.span, infer::FnCall, fn_sig);
+        let fn_sig = self.instantiate_binder_with_fresh_vars(call_expr.span, infer::FnCall, fn_sig);
         let fn_sig = self.normalize(call_expr.span, fn_sig);
 
         // Call the generic checker.
diff --git a/compiler/rustc_hir_typeck/src/closure.rs b/compiler/rustc_hir_typeck/src/closure.rs
index 90c4e5b6540..211fe477a2d 100644
--- a/compiler/rustc_hir_typeck/src/closure.rs
+++ b/compiler/rustc_hir_typeck/src/closure.rs
@@ -544,7 +544,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             )
             .map(|(hir_ty, &supplied_ty)| {
                 // Instantiate (this part of..) S to S', i.e., with fresh variables.
-                self.replace_bound_vars_with_fresh_vars(
+                self.instantiate_binder_with_fresh_vars(
                     hir_ty.span,
                     LateBoundRegionConversionTime::FnCall,
                     // (*) binder moved to here
@@ -566,7 +566,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 all_obligations.extend(obligations);
             }
 
-            let supplied_output_ty = self.replace_bound_vars_with_fresh_vars(
+            let supplied_output_ty = self.instantiate_binder_with_fresh_vars(
                 decl.output.span(),
                 LateBoundRegionConversionTime::FnCall,
                 supplied_sig.output(),
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 3561992e86a..bb235a48361 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -568,7 +568,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     // placeholder lifetimes with probing, we just replace higher lifetimes
                     // with fresh vars.
                     let span = args.get(i).map(|a| a.span).unwrap_or(expr.span);
-                    let input = self.replace_bound_vars_with_fresh_vars(
+                    let input = self.instantiate_binder_with_fresh_vars(
                         span,
                         infer::LateBoundRegionConversionTime::FnCall,
                         fn_sig.input(i),
@@ -586,7 +586,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // Also, as we just want to check sizedness, instead of introducing
             // placeholder lifetimes with probing, we just replace higher lifetimes
             // with fresh vars.
-            let output = self.replace_bound_vars_with_fresh_vars(
+            let output = self.instantiate_binder_with_fresh_vars(
                 expr.span,
                 infer::LateBoundRegionConversionTime::FnCall,
                 fn_sig.output(),
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
index 1e14eddd4c8..3814ddaf73f 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
@@ -289,7 +289,7 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
         item_segment: &hir::PathSegment<'_>,
         poly_trait_ref: ty::PolyTraitRef<'tcx>,
     ) -> Ty<'tcx> {
-        let trait_ref = self.replace_bound_vars_with_fresh_vars(
+        let trait_ref = self.instantiate_binder_with_fresh_vars(
             span,
             infer::LateBoundRegionConversionTime::AssocTypeProjection(item_def_id),
             poly_trait_ref,
diff --git a/compiler/rustc_hir_typeck/src/method/confirm.rs b/compiler/rustc_hir_typeck/src/method/confirm.rs
index 65ca47bfe53..fa0dc4d8415 100644
--- a/compiler/rustc_hir_typeck/src/method/confirm.rs
+++ b/compiler/rustc_hir_typeck/src/method/confirm.rs
@@ -262,7 +262,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
                     let original_poly_trait_ref = principal.with_self_ty(this.tcx, object_ty);
                     let upcast_poly_trait_ref = this.upcast(original_poly_trait_ref, trait_def_id);
                     let upcast_trait_ref =
-                        this.replace_bound_vars_with_fresh_vars(upcast_poly_trait_ref);
+                        this.instantiate_binder_with_fresh_vars(upcast_poly_trait_ref);
                     debug!(
                         "original_poly_trait_ref={:?} upcast_trait_ref={:?} target_trait={:?}",
                         original_poly_trait_ref, upcast_trait_ref, trait_def_id
@@ -285,7 +285,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
             probe::WhereClausePick(poly_trait_ref) => {
                 // Where clauses can have bound regions in them. We need to instantiate
                 // those to convert from a poly-trait-ref to a trait-ref.
-                self.replace_bound_vars_with_fresh_vars(poly_trait_ref).substs
+                self.instantiate_binder_with_fresh_vars(poly_trait_ref).substs
             }
         }
     }
@@ -506,7 +506,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
         let sig = self.tcx.fn_sig(def_id).subst(self.tcx, all_substs);
         debug!("type scheme substituted, sig={:?}", sig);
 
-        let sig = self.replace_bound_vars_with_fresh_vars(sig);
+        let sig = self.instantiate_binder_with_fresh_vars(sig);
         debug!("late-bound lifetimes from method instantiated, sig={:?}", sig);
 
         (sig, method_predicates)
@@ -625,10 +625,10 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
         upcast_trait_refs.into_iter().next().unwrap()
     }
 
-    fn replace_bound_vars_with_fresh_vars<T>(&self, value: ty::Binder<'tcx, T>) -> T
+    fn instantiate_binder_with_fresh_vars<T>(&self, value: ty::Binder<'tcx, T>) -> T
     where
         T: TypeFoldable<'tcx> + Copy,
     {
-        self.fcx.replace_bound_vars_with_fresh_vars(self.span, infer::FnCall, value)
+        self.fcx.instantiate_binder_with_fresh_vars(self.span, infer::FnCall, value)
     }
 }
diff --git a/compiler/rustc_hir_typeck/src/method/mod.rs b/compiler/rustc_hir_typeck/src/method/mod.rs
index 60d4dc326ee..d5d10cf272a 100644
--- a/compiler/rustc_hir_typeck/src/method/mod.rs
+++ b/compiler/rustc_hir_typeck/src/method/mod.rs
@@ -401,7 +401,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // with bound regions.
         let fn_sig = tcx.fn_sig(def_id).subst(self.tcx, substs);
         let fn_sig =
-            self.replace_bound_vars_with_fresh_vars(obligation.cause.span, infer::FnCall, fn_sig);
+            self.instantiate_binder_with_fresh_vars(obligation.cause.span, infer::FnCall, fn_sig);
 
         let InferOk { value, obligations: o } =
             self.at(&obligation.cause, self.param_env).normalize(fn_sig);
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
index 9ab29a6778f..4ce401b52bd 100644
--- a/compiler/rustc_hir_typeck/src/method/probe.rs
+++ b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -924,7 +924,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             ty::AssocKind::Fn => self.probe(|_| {
                 let substs = self.fresh_substs_for_item(self.span, method.def_id);
                 let fty = self.tcx.fn_sig(method.def_id).subst(self.tcx, substs);
-                let fty = self.replace_bound_vars_with_fresh_vars(self.span, infer::FnCall, fty);
+                let fty = self.instantiate_binder_with_fresh_vars(self.span, infer::FnCall, fty);
 
                 if let Some(self_ty) = self_ty {
                     if self
diff --git a/compiler/rustc_infer/src/infer/equate.rs b/compiler/rustc_infer/src/infer/equate.rs
index 46e7813d99e..7db4d92a177 100644
--- a/compiler/rustc_infer/src/infer/equate.rs
+++ b/compiler/rustc_infer/src/infer/equate.rs
@@ -129,7 +129,7 @@ impl<'tcx> TypeRelation<'tcx> for Equate<'_, '_, 'tcx> {
                 let a_types = infcx.tcx.anonymize_bound_vars(a_types);
                 let b_types = infcx.tcx.anonymize_bound_vars(b_types);
                 if a_types.bound_vars() == b_types.bound_vars() {
-                    let (a_types, b_types) = infcx.replace_bound_vars_with_placeholders(
+                    let (a_types, b_types) = infcx.instantiate_binder_with_placeholders(
                         a_types.map_bound(|a_types| (a_types, b_types.skip_binder())),
                     );
                     for (a, b) in std::iter::zip(a_types, b_types) {
diff --git a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
index 31be107b354..412e52d8fd7 100644
--- a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
+++ b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
@@ -38,13 +38,13 @@ impl<'a, 'tcx> CombineFields<'a, 'tcx> {
         // First, we instantiate each bound region in the supertype with a
         // fresh placeholder region. Note that this automatically creates
         // a new universe if needed.
-        let sup_prime = self.infcx.replace_bound_vars_with_placeholders(sup);
+        let sup_prime = self.infcx.instantiate_binder_with_placeholders(sup);
 
         // Next, we instantiate each bound region in the subtype
         // with a fresh region variable. These region variables --
         // but no other pre-existing region variables -- can name
         // the placeholders.
-        let sub_prime = self.infcx.replace_bound_vars_with_fresh_vars(span, HigherRankedType, sub);
+        let sub_prime = self.infcx.instantiate_binder_with_fresh_vars(span, HigherRankedType, sub);
 
         debug!("a_prime={:?}", sub_prime);
         debug!("b_prime={:?}", sup_prime);
@@ -70,7 +70,7 @@ impl<'tcx> InferCtxt<'tcx> {
     ///
     /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html
     #[instrument(level = "debug", skip(self), ret)]
-    pub fn replace_bound_vars_with_placeholders<T>(&self, binder: ty::Binder<'tcx, T>) -> T
+    pub fn instantiate_binder_with_placeholders<T>(&self, binder: ty::Binder<'tcx, T>) -> T
     where
         T: TypeFoldable<'tcx> + Copy,
     {
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index 8e0bcff8d0a..35918b8bae1 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -995,7 +995,7 @@ impl<'tcx> InferCtxt<'tcx> {
 
         Ok(self.commit_if_ok(|_snapshot| {
             let ty::SubtypePredicate { a_is_expected, a, b } =
-                self.replace_bound_vars_with_placeholders(predicate);
+                self.instantiate_binder_with_placeholders(predicate);
 
             let ok = self.at(cause, param_env).sub_exp(a_is_expected, a, b)?;
 
@@ -1008,7 +1008,7 @@ impl<'tcx> InferCtxt<'tcx> {
         cause: &traits::ObligationCause<'tcx>,
         predicate: ty::PolyRegionOutlivesPredicate<'tcx>,
     ) {
-        let ty::OutlivesPredicate(r_a, r_b) = self.replace_bound_vars_with_placeholders(predicate);
+        let ty::OutlivesPredicate(r_a, r_b) = self.instantiate_binder_with_placeholders(predicate);
         let origin =
             SubregionOrigin::from_obligation_cause(cause, || RelateRegionParamBound(cause.span));
         self.sub_regions(origin, r_b, r_a); // `b : a` ==> `a <= b`
@@ -1447,7 +1447,14 @@ impl<'tcx> InferCtxt<'tcx> {
         value
     }
 
-    pub fn replace_bound_vars_with_fresh_vars<T>(
+    // Instantiates the bound variables in a given binder with fresh inference
+    // variables in the current universe.
+    //
+    // Use this method if you'd like to find some substitution of the binder's
+    // variables (e.g. during a method call). If there isn't a [`LateBoundRegionConversionTime`]
+    // that corresponds to your use case, consider whether or not you should
+    // use [`InferCtxt::instantiate_binder_with_placeholders`] instead.
+    pub fn instantiate_binder_with_fresh_vars<T>(
         &self,
         span: Span,
         lbrct: LateBoundRegionConversionTime,
diff --git a/compiler/rustc_infer/src/infer/sub.rs b/compiler/rustc_infer/src/infer/sub.rs
index 51c34f0d55f..532fbd0ffe4 100644
--- a/compiler/rustc_infer/src/infer/sub.rs
+++ b/compiler/rustc_infer/src/infer/sub.rs
@@ -161,7 +161,7 @@ impl<'tcx> TypeRelation<'tcx> for Sub<'_, '_, 'tcx> {
                 let a_types = infcx.tcx.anonymize_bound_vars(a_types);
                 let b_types = infcx.tcx.anonymize_bound_vars(b_types);
                 if a_types.bound_vars() == b_types.bound_vars() {
-                    let (a_types, b_types) = infcx.replace_bound_vars_with_placeholders(
+                    let (a_types, b_types) = infcx.instantiate_binder_with_placeholders(
                         a_types.map_bound(|a_types| (a_types, b_types.skip_binder())),
                     );
                     for (a, b) in std::iter::zip(a_types, b_types) {
diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs
index a2c15123b4f..c1936b7dbe4 100644
--- a/compiler/rustc_trait_selection/src/solve/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs
@@ -74,7 +74,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
                                     )
                                 }
                                 ty::PredicateKind::Subtype(pred) => {
-                                    let (a, b) = infcx.replace_bound_vars_with_placeholders(
+                                    let (a, b) = infcx.instantiate_binder_with_placeholders(
                                         goal.predicate.kind().rebind((pred.a, pred.b)),
                                     );
                                     let expected_found = ExpectedFound::new(true, a, b);
@@ -84,7 +84,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
                                     )
                                 }
                                 ty::PredicateKind::Coerce(pred) => {
-                                    let (a, b) = infcx.replace_bound_vars_with_placeholders(
+                                    let (a, b) = infcx.instantiate_binder_with_placeholders(
                                         goal.predicate.kind().rebind((pred.a, pred.b)),
                                     );
                                     let expected_found = ExpectedFound::new(false, a, b);
@@ -94,7 +94,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
                                     )
                                 }
                                 ty::PredicateKind::ConstEquate(a, b) => {
-                                    let (a, b) = infcx.replace_bound_vars_with_placeholders(
+                                    let (a, b) = infcx.instantiate_binder_with_placeholders(
                                         goal.predicate.kind().rebind((a, b)),
                                     );
                                     let expected_found = ExpectedFound::new(true, a, b);
diff --git a/compiler/rustc_trait_selection/src/solve/infcx_ext.rs b/compiler/rustc_trait_selection/src/solve/infcx_ext.rs
index 42f597c781d..36f987c9f9c 100644
--- a/compiler/rustc_trait_selection/src/solve/infcx_ext.rs
+++ b/compiler/rustc_trait_selection/src/solve/infcx_ext.rs
@@ -26,7 +26,7 @@ pub(super) trait InferCtxtExt<'tcx> {
         rhs: T,
     ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution>;
 
-    fn instantiate_bound_vars_with_infer<T: TypeFoldable<'tcx> + Copy>(
+    fn instantiate_binder_with_infer<T: TypeFoldable<'tcx> + Copy>(
         &self,
         value: ty::Binder<'tcx, T>,
     ) -> T;
@@ -65,11 +65,11 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
             })
     }
 
-    fn instantiate_bound_vars_with_infer<T: TypeFoldable<'tcx> + Copy>(
+    fn instantiate_binder_with_infer<T: TypeFoldable<'tcx> + Copy>(
         &self,
         value: ty::Binder<'tcx, T>,
     ) -> T {
-        self.replace_bound_vars_with_fresh_vars(
+        self.instantiate_binder_with_fresh_vars(
             DUMMY_SP,
             LateBoundRegionConversionTime::HigherRankedType,
             value,
diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs
index e4725c0a1b7..9f092b6018f 100644
--- a/compiler/rustc_trait_selection/src/solve/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/mod.rs
@@ -304,7 +304,7 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
                 }
             }
         } else {
-            let kind = self.infcx.replace_bound_vars_with_placeholders(kind);
+            let kind = self.infcx.instantiate_binder_with_placeholders(kind);
             let goal = goal.with(self.tcx(), ty::Binder::dummy(kind));
             let (_, certainty) = self.evaluate_goal(goal)?;
             self.make_canonical_response(certainty)
diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs
index f9acf7a53ee..e3ec71d1b4f 100644
--- a/compiler/rustc_trait_selection/src/solve/project_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs
@@ -323,7 +323,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
         {
             ecx.infcx.probe(|_| {
                 let assumption_projection_pred =
-                    ecx.infcx.instantiate_bound_vars_with_infer(poly_projection_pred);
+                    ecx.infcx.instantiate_binder_with_infer(poly_projection_pred);
                 let nested_goals = ecx.infcx.eq(
                     goal.param_env,
                     goal.predicate.projection_ty,
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index 1cf1efc9704..06a72e95d49 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -72,7 +72,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
             // FIXME: Constness and polarity
             ecx.infcx.probe(|_| {
                 let assumption_trait_pred =
-                    ecx.infcx.instantiate_bound_vars_with_infer(poly_trait_pred);
+                    ecx.infcx.instantiate_binder_with_infer(poly_trait_pred);
                 let nested_goals = ecx.infcx.eq(
                     goal.param_env,
                     goal.predicate.trait_ref,
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs
index 5007a019e18..1ee35a86e62 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs
@@ -54,7 +54,7 @@ pub(super) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
         }
 
         ty::GeneratorWitness(types) => {
-            Ok(infcx.replace_bound_vars_with_placeholders(types).to_vec())
+            Ok(infcx.instantiate_binder_with_placeholders(types).to_vec())
         }
 
         ty::GeneratorWitnessMIR(..) => todo!(),
@@ -174,7 +174,7 @@ pub(super) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>(
         }
 
         ty::GeneratorWitness(types) => {
-            Ok(infcx.replace_bound_vars_with_placeholders(types).to_vec())
+            Ok(infcx.instantiate_binder_with_placeholders(types).to_vec())
         }
 
         ty::GeneratorWitnessMIR(..) => todo!(),
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
index 6bf453c3ff0..84045c4d0ed 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
@@ -22,7 +22,7 @@ pub fn recompute_applicable_impls<'tcx>(
     let impl_may_apply = |impl_def_id| {
         let ocx = ObligationCtxt::new_in_snapshot(infcx);
         let placeholder_obligation =
-            infcx.replace_bound_vars_with_placeholders(obligation.predicate);
+            infcx.instantiate_binder_with_placeholders(obligation.predicate);
         let obligation_trait_ref =
             ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref);
 
@@ -47,11 +47,11 @@ pub fn recompute_applicable_impls<'tcx>(
     let param_env_candidate_may_apply = |poly_trait_predicate: ty::PolyTraitPredicate<'tcx>| {
         let ocx = ObligationCtxt::new_in_snapshot(infcx);
         let placeholder_obligation =
-            infcx.replace_bound_vars_with_placeholders(obligation.predicate);
+            infcx.instantiate_binder_with_placeholders(obligation.predicate);
         let obligation_trait_ref =
             ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref);
 
-        let param_env_predicate = infcx.replace_bound_vars_with_fresh_vars(
+        let param_env_predicate = infcx.instantiate_binder_with_fresh_vars(
             DUMMY_SP,
             LateBoundRegionConversionTime::HigherRankedType,
             poly_trait_predicate,
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index f6d0b9713f0..cf1e05ada47 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -1716,7 +1716,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             let (values, err) = if let ty::PredicateKind::Clause(ty::Clause::Projection(data)) =
                 bound_predicate.skip_binder()
             {
-                let data = self.replace_bound_vars_with_fresh_vars(
+                let data = self.instantiate_binder_with_fresh_vars(
                     obligation.cause.span,
                     infer::LateBoundRegionConversionTime::HigherRankedType,
                     bound_predicate.rebind(data),
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index 91da690a000..59aef52910e 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -898,7 +898,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             return false;
         }
 
-        let self_ty = self.replace_bound_vars_with_fresh_vars(
+        let self_ty = self.instantiate_binder_with_fresh_vars(
             DUMMY_SP,
             LateBoundRegionConversionTime::FnCall,
             trait_pred.self_ty(),
@@ -1191,7 +1191,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             }
         }) else { return None; };
 
-        let output = self.replace_bound_vars_with_fresh_vars(
+        let output = self.instantiate_binder_with_fresh_vars(
             DUMMY_SP,
             LateBoundRegionConversionTime::FnCall,
             output,
@@ -1200,7 +1200,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             .skip_binder()
             .iter()
             .map(|ty| {
-                self.replace_bound_vars_with_fresh_vars(
+                self.instantiate_binder_with_fresh_vars(
                     DUMMY_SP,
                     LateBoundRegionConversionTime::FnCall,
                     inputs.rebind(*ty),
@@ -3806,13 +3806,13 @@ fn hint_missing_borrow<'tcx>(
     err: &mut Diagnostic,
 ) {
     let found_args = match found.kind() {
-        ty::FnPtr(f) => infcx.replace_bound_vars_with_placeholders(*f).inputs().iter(),
+        ty::FnPtr(f) => infcx.instantiate_binder_with_placeholders(*f).inputs().iter(),
         kind => {
             span_bug!(span, "found was converted to a FnPtr above but is now {:?}", kind)
         }
     };
     let expected_args = match expected.kind() {
-        ty::FnPtr(f) => infcx.replace_bound_vars_with_placeholders(*f).inputs().iter(),
+        ty::FnPtr(f) => infcx.instantiate_binder_with_placeholders(*f).inputs().iter(),
         kind => {
             span_bug!(span, "expected was converted to a FnPtr above but is now {:?}", kind)
         }
diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
index 18d30771035..3adc1e62e0d 100644
--- a/compiler/rustc_trait_selection/src/traits/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -321,7 +321,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 | ty::PredicateKind::ConstEvaluatable(..)
                 | ty::PredicateKind::ConstEquate(..) => {
                     let pred =
-                        ty::Binder::dummy(infcx.replace_bound_vars_with_placeholders(binder));
+                        ty::Binder::dummy(infcx.instantiate_binder_with_placeholders(binder));
                     ProcessResult::Changed(mk_pending(vec![obligation.with(infcx.tcx, pred)]))
                 }
                 ty::PredicateKind::Ambiguous => ProcessResult::Unchanged,
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index 53cae3e720c..aa81bc640aa 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -215,7 +215,7 @@ pub(super) fn poly_project_and_unify_type<'cx, 'tcx>(
     let r = infcx.commit_if_ok(|_snapshot| {
         let old_universe = infcx.universe();
         let placeholder_predicate =
-            infcx.replace_bound_vars_with_placeholders(obligation.predicate);
+            infcx.instantiate_binder_with_placeholders(obligation.predicate);
         let new_universe = infcx.universe();
 
         let placeholder_obligation = obligation.with(infcx.tcx, placeholder_predicate);
@@ -2046,7 +2046,7 @@ fn confirm_param_env_candidate<'cx, 'tcx>(
     let cause = &obligation.cause;
     let param_env = obligation.param_env;
 
-    let cache_entry = infcx.replace_bound_vars_with_fresh_vars(
+    let cache_entry = infcx.instantiate_binder_with_fresh_vars(
         cause.span,
         LateBoundRegionConversionTime::HigherRankedType,
         poly_cache_entry,
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index bba07ed965b..e9f7c3bc4cc 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -488,7 +488,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
             let poly_trait_predicate = self.infcx.resolve_vars_if_possible(obligation.predicate);
             let placeholder_trait_predicate =
-                self.infcx.replace_bound_vars_with_placeholders(poly_trait_predicate);
+                self.infcx.instantiate_binder_with_placeholders(poly_trait_predicate);
 
             // Count only those upcast versions that match the trait-ref
             // we are looking for. Specifically, do not only check for the
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 94d9eb8f587..fcc4820c2a6 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -151,7 +151,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         let trait_predicate = self.infcx.shallow_resolve(obligation.predicate);
         let placeholder_trait_predicate =
-            self.infcx.replace_bound_vars_with_placeholders(trait_predicate).trait_ref;
+            self.infcx.instantiate_binder_with_placeholders(trait_predicate).trait_ref;
         let placeholder_self_ty = placeholder_trait_predicate.self_ty();
         let placeholder_trait_predicate = ty::Binder::dummy(placeholder_trait_predicate);
         let (def_id, substs) = match *placeholder_self_ty.kind() {
@@ -336,7 +336,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             let cause = obligation.derived_cause(BuiltinDerivedObligation);
 
             let poly_trait_ref = obligation.predicate.to_poly_trait_ref();
-            let trait_ref = self.infcx.replace_bound_vars_with_placeholders(poly_trait_ref);
+            let trait_ref = self.infcx.instantiate_binder_with_placeholders(poly_trait_ref);
             let trait_obligations: Vec<PredicateObligation<'_>> = self.impl_or_trait_obligations(
                 &cause,
                 obligation.recursion_depth + 1,
@@ -427,7 +427,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let tcx = self.tcx();
         debug!(?obligation, ?index, "confirm_object_candidate");
 
-        let trait_predicate = self.infcx.replace_bound_vars_with_placeholders(obligation.predicate);
+        let trait_predicate = self.infcx.instantiate_binder_with_placeholders(obligation.predicate);
         let self_ty = self.infcx.shallow_resolve(trait_predicate.self_ty());
         let obligation_trait_ref = ty::Binder::dummy(trait_predicate.trait_ref);
         let ty::Dynamic(data, ..) = *self_ty.kind() else {
@@ -437,7 +437,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         let object_trait_ref = data.principal().unwrap_or_else(|| {
             span_bug!(obligation.cause.span, "object candidate with no principal")
         });
-        let object_trait_ref = self.infcx.replace_bound_vars_with_fresh_vars(
+        let object_trait_ref = self.infcx.instantiate_binder_with_fresh_vars(
             obligation.cause.span,
             HigherRankedType,
             object_trait_ref,
@@ -629,7 +629,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         }
 
         // Confirm the `type Output: Sized;` bound that is present on `FnOnce`
-        let output_ty = self.infcx.replace_bound_vars_with_placeholders(sig.output());
+        let output_ty = self.infcx.instantiate_binder_with_placeholders(sig.output());
         let output_ty = normalize_with_depth_to(
             self,
             obligation.param_env,
@@ -652,7 +652,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         debug!(?obligation, "confirm_trait_alias_candidate");
 
         let alias_def_id = obligation.predicate.def_id();
-        let predicate = self.infcx.replace_bound_vars_with_placeholders(obligation.predicate);
+        let predicate = self.infcx.instantiate_binder_with_placeholders(obligation.predicate);
         let trait_ref = predicate.trait_ref;
         let trait_def_id = trait_ref.def_id;
         let substs = trait_ref.substs;
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 0c6b2406bbd..984d6fde268 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1618,7 +1618,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     ) -> smallvec::SmallVec<[(usize, ty::BoundConstness); 2]> {
         let poly_trait_predicate = self.infcx.resolve_vars_if_possible(obligation.predicate);
         let placeholder_trait_predicate =
-            self.infcx.replace_bound_vars_with_placeholders(poly_trait_predicate);
+            self.infcx.instantiate_binder_with_placeholders(poly_trait_predicate);
         debug!(?placeholder_trait_predicate);
 
         let tcx = self.infcx.tcx;
@@ -1738,7 +1738,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         potentially_unnormalized_candidates: bool,
     ) -> ProjectionMatchesProjection {
         let mut nested_obligations = Vec::new();
-        let infer_predicate = self.infcx.replace_bound_vars_with_fresh_vars(
+        let infer_predicate = self.infcx.instantiate_binder_with_fresh_vars(
             obligation.cause.span,
             LateBoundRegionConversionTime::HigherRankedType,
             env_predicate,
@@ -2339,7 +2339,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             .flat_map(|ty| {
                 let ty: ty::Binder<'tcx, Ty<'tcx>> = types.rebind(*ty); // <----/
 
-                let placeholder_ty = self.infcx.replace_bound_vars_with_placeholders(ty);
+                let placeholder_ty = self.infcx.instantiate_binder_with_placeholders(ty);
                 let Normalized { value: normalized_ty, mut obligations } =
                     ensure_sufficient_stack(|| {
                         project::normalize_with_depth(
@@ -2418,7 +2418,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         obligation: &TraitObligation<'tcx>,
     ) -> Result<Normalized<'tcx, SubstsRef<'tcx>>, ()> {
         let placeholder_obligation =
-            self.infcx.replace_bound_vars_with_placeholders(obligation.predicate);
+            self.infcx.instantiate_binder_with_placeholders(obligation.predicate);
         let placeholder_obligation_trait_ref = placeholder_obligation.trait_ref;
 
         let impl_substs = self.infcx.fresh_substs_for_item(obligation.cause.span, impl_def_id);