Stop passing the self-type as a separate argument.

Author: oli-obk

clippy_lints/src/dereference.rs

@@ -842,14 +842,10 @@ fn walk_parents<'tcx>(
                         } else if let Some(trait_id) = cx.tcx.trait_of_item(id)
                             && let arg_ty = cx.tcx.erase_regions(cx.typeck_results().expr_ty_adjusted(e))
                             && let ty::Ref(_, sub_ty, _) = *arg_ty.kind()
-                            && let subs = match cx
+                            && let subs = cx
                                 .typeck_results()
-                                .node_substs_opt(parent.hir_id)
-                                .and_then(|subs| subs.get(1..))
-                            {
-                                Some(subs) => cx.tcx.mk_substs(subs.iter().copied()),
-                                None => cx.tcx.mk_substs(std::iter::empty::<ty::subst::GenericArg<'_>>()),
-                            } && let impl_ty = if cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref() {
+                                .node_substs_opt(parent.hir_id).map(|subs| &subs[1..]).unwrap_or_default()
+                            && let impl_ty = if cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref() {
                                 // Trait methods taking `&self`
                                 sub_ty
                             } else {
@@ -858,7 +854,7 @@ fn walk_parents<'tcx>(
                             } && impl_ty.is_ref()
                             && let infcx = cx.tcx.infer_ctxt().build()
                             && infcx
-                                .type_implements_trait(trait_id, impl_ty, subs, cx.param_env)
+                                .type_implements_trait(trait_id, [impl_ty.into()].into_iter().chain(subs.iter().copied()), cx.param_env)
                                 .must_apply_modulo_regions()
                         {
                             return Some(Position::MethodReceiverRefImpl)

clippy_lints/src/ptr.rs

@@ -692,7 +692,7 @@ fn matches_preds<'tcx>(
     let infcx = cx.tcx.infer_ctxt().build();
     preds.iter().all(|&p| match cx.tcx.erase_late_bound_regions(p) {
         ExistentialPredicate::Trait(p) => infcx
-            .type_implements_trait(p.def_id, ty, p.substs, cx.param_env)
+            .type_implements_trait(p.def_id, [ty.into()].into_iter().chain(p.substs.iter()), cx.param_env)
             .must_apply_modulo_regions(),
         ExistentialPredicate::Projection(p) => infcx.predicate_must_hold_modulo_regions(&Obligation::new(
             cx.tcx,
@@ -704,7 +704,7 @@ fn matches_preds<'tcx>(
             )),
         )),
         ExistentialPredicate::AutoTrait(p) => infcx
-            .type_implements_trait(p, ty, List::empty(), cx.param_env)
+            .type_implements_trait(p, [ty], cx.param_env)
             .must_apply_modulo_regions(),
     })
 }

clippy_utils/src/ty.rs

@@ -178,7 +178,7 @@ pub fn implements_trait_with_env<'tcx>(
     };
     let ty_params = tcx.mk_substs(ty_params.into_iter().map(|arg| arg.unwrap_or_else(|| infcx.next_ty_var(orig).into())));
     infcx
-        .type_implements_trait(trait_id, ty, ty_params, param_env)
+        .type_implements_trait(trait_id, [ty.into()].into_iter().chain(ty_params), param_env)
         .must_apply_modulo_regions()
 }