Add `TyCtxt::is_fn_trait`

3 files changed, 6 insertions, 9 deletions

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 de35fbfe6d0..e96b9b64e78 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -687,7 +687,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                                 }
                                 ObligationCauseCode::BindingObligation(def_id, _)
                                 | ObligationCauseCode::ItemObligation(def_id)
-                                    if tcx.fn_trait_kind_from_def_id(*def_id).is_some() =>
+                                    if tcx.is_fn_trait(*def_id) =>
                                 {
                                     err.code(rustc_errors::error_code!(E0059));
                                     err.set_primary_message(format!(
@@ -847,8 +847,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                             );
                         }
 
-                        let is_fn_trait =
-                            tcx.fn_trait_kind_from_def_id(trait_ref.def_id()).is_some();
+                        let is_fn_trait = tcx.is_fn_trait(trait_ref.def_id());
                         let is_target_feature_fn = if let ty::FnDef(def_id, _) =
                             *trait_ref.skip_binder().self_ty().kind()
                         {
@@ -2156,7 +2155,7 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     if generics.params.iter().any(|p| p.name != kw::SelfUpper)
                         && !snippet.ends_with('>')
                         && !generics.has_impl_trait()
-                        && !self.tcx.fn_trait_kind_from_def_id(def_id).is_some()
+                        && !self.tcx.is_fn_trait(def_id)
                     {
                         // FIXME: To avoid spurious suggestions in functions where type arguments
                         // where already supplied, we check the snippet to make sure it doesn't
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 4ae9b22f221..ddffe25bc26 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -1679,9 +1679,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         ) -> Ty<'tcx> {
             let inputs = trait_ref.skip_binder().substs.type_at(1);
             let sig = match inputs.kind() {
-                ty::Tuple(inputs)
-                    if infcx.tcx.fn_trait_kind_from_def_id(trait_ref.def_id()).is_some() =>
-                {
+                ty::Tuple(inputs) if infcx.tcx.is_fn_trait(trait_ref.def_id()) => {
                     infcx.tcx.mk_fn_sig(
                         inputs.iter(),
                         infcx.next_ty_var(TypeVariableOrigin {
@@ -1752,7 +1750,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             && let predicates = self.tcx.predicates_of(def_id).instantiate_identity(self.tcx)
             && let Some(pred) = predicates.predicates.get(*idx)
             && let ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) = pred.kind().skip_binder()
-            && self.tcx.fn_trait_kind_from_def_id(trait_pred.def_id()).is_some()
+            && self.tcx.is_fn_trait(trait_pred.def_id())
         {
             let expected_self =
                 self.tcx.anonymize_late_bound_regions(pred.kind().rebind(trait_pred.self_ty()));
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 460ca923c6e..adce549a858 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -489,7 +489,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         candidates: &mut SelectionCandidateSet<'tcx>,
     ) {
         // We provide impl of all fn traits for fn pointers.
-        if self.tcx().fn_trait_kind_from_def_id(obligation.predicate.def_id()).is_none() {
+        if !self.tcx().is_fn_trait(obligation.predicate.def_id()) {
             return;
         }