Remove dead/useless code

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -230,8 +230,6 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> {
                 }
             }
 
-            self.check_item_predicates();
-
             for (idx, local) in body.local_decls.iter_enumerated() {
                 // Handle the return place below.
                 if idx == RETURN_PLACE || local.internal {
@@ -364,40 +362,6 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> {
         }
     }
 
-    fn check_item_predicates(&mut self) {
-        let ConstCx { tcx, .. } = *self.ccx;
-
-        let mut current = self.def_id().to_def_id();
-        loop {
-            let predicates = tcx.predicates_of(current);
-            for (predicate, _) in predicates.predicates {
-                match predicate.kind().skip_binder() {
-                    ty::PredicateKind::RegionOutlives(_)
-                    | ty::PredicateKind::TypeOutlives(_)
-                    | ty::PredicateKind::WellFormed(_)
-                    | ty::PredicateKind::Projection(_)
-                    | ty::PredicateKind::ConstEvaluatable(..)
-                    | ty::PredicateKind::ConstEquate(..)
-                    | ty::PredicateKind::Trait(..)
-                    | ty::PredicateKind::TypeWellFormedFromEnv(..) => continue,
-                    ty::PredicateKind::ObjectSafe(_) => {
-                        bug!("object safe predicate on function: {:#?}", predicate)
-                    }
-                    ty::PredicateKind::ClosureKind(..) => {
-                        bug!("closure kind predicate on function: {:#?}", predicate)
-                    }
-                    ty::PredicateKind::Subtype(_) | ty::PredicateKind::Coerce(_) => {
-                        bug!("subtype/coerce predicate on function: {:#?}", predicate)
-                    }
-                }
-            }
-            match predicates.parent {
-                Some(parent) => current = parent,
-                None => break,
-            }
-        }
-    }
-
     fn check_mut_borrow(&mut self, local: Local, kind: hir::BorrowKind) {
         match self.const_kind() {
             // In a const fn all borrows are transient or point to the places given via

compiler/rustc_const_eval/src/transform/check_consts/ops.rs

@@ -816,26 +816,4 @@ pub mod ty {
             )
         }
     }
-
-    /// A trait bound with the `?const Trait` opt-out
-    #[derive(Debug)]
-    pub struct TraitBoundNotConst;
-    impl<'tcx> NonConstOp<'tcx> for TraitBoundNotConst {
-        fn status_in_item(&self, _: &ConstCx<'_, 'tcx>) -> Status {
-            Status::Unstable(sym::const_trait_bound_opt_out)
-        }
-
-        fn build_error(
-            &self,
-            ccx: &ConstCx<'_, 'tcx>,
-            span: Span,
-        ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
-            feature_err(
-                &ccx.tcx.sess.parse_sess,
-                sym::const_trait_bound_opt_out,
-                span,
-                "`?const Trait` syntax is unstable",
-            )
-        }
-    }
 }