Stop passing the self-type as a separate argument.

Author: oli-obk

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -489,12 +489,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             // but the type has region variables, so erase those.
             tcx.infer_ctxt()
                 .build()
-                .type_implements_trait(
-                    default_trait,
-                    tcx.erase_regions(ty),
-                    ty::List::empty(),
-                    param_env,
-                )
+                .type_implements_trait(default_trait, [tcx.erase_regions(ty)], param_env)
                 .must_apply_modulo_regions()
         };
 
@@ -1707,7 +1702,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             err.span_label(borrow_span, note);
 
             let tcx = self.infcx.tcx;
-            let ty_params = ty::List::empty();
 
             let return_ty = self.regioncx.universal_regions().unnormalized_output_ty;
             let return_ty = tcx.erase_regions(return_ty);
@@ -1716,7 +1710,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             if let Some(iter_trait) = tcx.get_diagnostic_item(sym::Iterator)
                 && self
                     .infcx
-                    .type_implements_trait(iter_trait, return_ty, ty_params, self.param_env)
+                    .type_implements_trait(iter_trait, [return_ty], self.param_env)
                     .must_apply_modulo_regions()
             {
                 err.span_suggestion_hidden(

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -547,7 +547,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
 
         if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
             let tcx = self.tcx();
-            let trait_ref = tcx.at(self.last_span).mk_trait_ref(LangItem::Copy, place_ty.ty, []);
+            let trait_ref = tcx.at(self.last_span).mk_trait_ref(LangItem::Copy, [place_ty.ty]);
 
             // To have a `Copy` operand, the type `T` of the
             // value must be `Copy`. Note that we prove that `T: Copy`,
@@ -1271,7 +1271,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 self.check_rvalue(body, rv, location);
                 if !self.unsized_feature_enabled() {
                     let trait_ref =
-                        tcx.at(self.last_span).mk_trait_ref(LangItem::Sized, place_ty, []);
+                        tcx.at(self.last_span).mk_trait_ref(LangItem::Sized, [place_ty]);
                     self.prove_trait_ref(
                         trait_ref,
                         location.to_locations(),
@@ -1860,7 +1860,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         Operand::Move(place) => {
                             // Make sure that repeated elements implement `Copy`.
                             let ty = place.ty(body, tcx).ty;
-                            let trait_ref = tcx.at(span).mk_trait_ref(LangItem::Copy, ty, []);
+                            let trait_ref = tcx.at(span).mk_trait_ref(LangItem::Copy, [ty]);
 
                             self.prove_trait_ref(
                                 trait_ref,
@@ -1873,7 +1873,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             }
 
             &Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf, ty) => {
-                let trait_ref = tcx.at(span).mk_trait_ref(LangItem::Sized, ty, []);
+                let trait_ref = tcx.at(span).mk_trait_ref(LangItem::Sized, [ty]);
 
                 self.prove_trait_ref(
                     trait_ref,
@@ -1885,7 +1885,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             Rvalue::ShallowInitBox(operand, ty) => {
                 self.check_operand(operand, location);
 
-                let trait_ref = tcx.at(span).mk_trait_ref(LangItem::Sized, *ty, []);
+                let trait_ref = tcx.at(span).mk_trait_ref(LangItem::Sized, [*ty]);
 
                 self.prove_trait_ref(
                     trait_ref,
@@ -1982,11 +1982,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
                     CastKind::Pointer(PointerCast::Unsize) => {
                         let &ty = ty;
-                        let trait_ref = tcx.at(span).mk_trait_ref(
-                            LangItem::CoerceUnsized,
-                            op.ty(body, tcx),
-                            [ty.into()],
-                        );
+                        let trait_ref = tcx
+                            .at(span)
+                            .mk_trait_ref(LangItem::CoerceUnsized, [op.ty(body, tcx), ty]);
 
                         self.prove_trait_ref(
                             trait_ref,

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

@@ -158,7 +158,7 @@ impl Qualif for NeedsNonConstDrop {
             ObligationCause::dummy_with_span(cx.body.span),
             cx.param_env,
             ty::Binder::dummy(ty::TraitPredicate {
-                trait_ref: cx.tcx.at(cx.body.span).mk_trait_ref(LangItem::Destruct, ty, []),
+                trait_ref: cx.tcx.at(cx.body.span).mk_trait_ref(LangItem::Destruct, [ty]),
                 constness: ty::BoundConstness::ConstIfConst,
                 polarity: ty::ImplPolarity::Positive,
             }),

compiler/rustc_hir_analysis/src/bounds.rs

@@ -62,7 +62,7 @@ impl<'tcx> Bounds<'tcx> {
         let sized_predicate = self.implicitly_sized.and_then(|span| {
             // FIXME: use tcx.at(span).mk_trait_ref(LangItem::Sized) here? This may make no-core code harder to write.
             let sized = tcx.lang_items().sized_trait()?;
-            let trait_ref = ty::Binder::dummy(tcx.mk_trait_ref(sized, param_ty, []));
+            let trait_ref = ty::Binder::dummy(tcx.mk_trait_ref(sized, [param_ty]));
             Some((trait_ref.without_const().to_predicate(tcx), span))
         });
 

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1782,7 +1782,7 @@ fn receiver_is_implemented<'tcx>(
     receiver_ty: Ty<'tcx>,
 ) -> bool {
     let tcx = wfcx.tcx();
-    let trait_ref = ty::Binder::dummy(tcx.mk_trait_ref(receiver_trait_def_id, receiver_ty, []));
+    let trait_ref = ty::Binder::dummy(tcx.mk_trait_ref(receiver_trait_def_id, [receiver_ty]));
 
     let obligation = traits::Obligation::new(tcx, cause, wfcx.param_env, trait_ref.without_const());
 

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -315,8 +315,7 @@ fn visit_implementation_of_dispatch_from_dyn<'tcx>(tcx: TyCtxt<'tcx>, impl_did:
                             cause.clone(),
                             dispatch_from_dyn_trait,
                             0,
-                            field.ty(tcx, substs_a),
-                            [field.ty(tcx, substs_b).into()],
+                            [field.ty(tcx, substs_a), field.ty(tcx, substs_b)],
                         )
                     }),
                 );
@@ -558,7 +557,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn
     // Register an obligation for `A: Trait<B>`.
     let cause = traits::ObligationCause::misc(span, impl_hir_id);
     let predicate =
-        predicate_for_trait_def(tcx, param_env, cause, trait_def_id, 0, source, [target.into()]);
+        predicate_for_trait_def(tcx, param_env, cause, trait_def_id, 0, [source, target]);
     let errors = traits::fully_solve_obligation(&infcx, predicate);
     if !errors.is_empty() {
         infcx.err_ctxt().report_fulfillment_errors(&errors, None);

compiler/rustc_hir_typeck/src/cast.rs

@@ -498,10 +498,9 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                         let ty = fcx.tcx.erase_regions(ty);
                         let expr_ty = fcx.resolve_vars_if_possible(self.expr_ty);
                         let expr_ty = fcx.tcx.erase_regions(expr_ty);
-                        let ty_params = fcx.tcx.mk_substs(std::iter::once(ty::GenericArg::from(expr_ty)));
                         if fcx
                             .infcx
-                            .type_implements_trait(from_trait, ty, ty_params, fcx.param_env)
+                            .type_implements_trait(from_trait, [ty, expr_ty], fcx.param_env)
                             .must_apply_modulo_regions()
                         {
                             label = false;

compiler/rustc_hir_typeck/src/coercion.rs

@@ -630,8 +630,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             cause,
             coerce_unsized_did,
             0,
-            coerce_source,
-            [coerce_target.into()]
+            [coerce_source, coerce_target]
         )];
 
         let mut has_unsized_tuple_coercion = false;
@@ -1086,8 +1085,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.infcx
                 .type_implements_trait(
                     self.tcx.lang_items().deref_mut_trait()?,
-                    expr_ty,
-                    ty::List::empty(),
+                    [expr_ty],
                     self.param_env,
                 )
                 .may_apply()

compiler/rustc_hir_typeck/src/expr.rs

@@ -1119,8 +1119,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     .infcx
                     .type_implements_trait(
                         self.tcx.lang_items().sized_trait().unwrap(),
-                        lhs_deref_ty,
-                        ty::List::empty(),
+                        [lhs_deref_ty],
                         self.param_env,
                     )
                     .may_apply();

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1095,7 +1095,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.param_env,
                 ty::Binder::dummy(self.tcx.mk_trait_ref(
                     into_def_id,
-                    expr_ty, [expected_ty.into()]
+                    [expr_ty, expected_ty]
                 ))
                 .to_poly_trait_predicate(),
             ))