move Constness into TraitPredicate

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

@@ -423,7 +423,7 @@ impl Checker<'mir, 'tcx> {
                     ty::PredicateKind::Subtype(_) => {
                         bug!("subtype predicate on function: {:#?}", predicate)
                     }
-                    ty::PredicateKind::Trait(pred, _constness) => {
+                    ty::PredicateKind::Trait(pred) => {
                         if Some(pred.def_id()) == tcx.lang_items().sized_trait() {
                             continue;
                         }
@@ -817,7 +817,10 @@ impl Visitor<'tcx> for Checker<'mir, 'tcx> {
                     let obligation = Obligation::new(
                         ObligationCause::dummy(),
                         param_env,
-                        Binder::dummy(TraitPredicate { trait_ref }),
+                        Binder::dummy(TraitPredicate {
+                            trait_ref,
+                            constness: hir::Constness::Const,
+                        }),
                     );
 
                     let implsrc = tcx.infer_ctxt().enter(|infcx| {

compiler/rustc_mir/src/transform/function_item_references.rs

@@ -132,7 +132,7 @@ impl<'a, 'tcx> FunctionItemRefChecker<'a, 'tcx> {
 
     /// If the given predicate is the trait `fmt::Pointer`, returns the bound parameter type.
     fn is_pointer_trait(&self, bound: &PredicateKind<'tcx>) -> Option<Ty<'tcx>> {
-        if let ty::PredicateKind::Trait(predicate, _) = bound {
+        if let ty::PredicateKind::Trait(predicate) = bound {
             if self.tcx.is_diagnostic_item(sym::pointer_trait, predicate.def_id()) {
                 Some(predicate.trait_ref.self_ty())
             } else {