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

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);

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,

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)

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,

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,

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!(),

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,

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),

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)
         }

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,

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,

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

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;

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);