Auto merge of #110806 - WaffleLapkin:unmkI, r=lcnr

Replace `tcx.mk_trait_ref` with `TraitRef::new`

First step in implementing rust-lang/compiler-team#616
r? `@lcnr`

compiler/rustc_borrowck/src/diagnostics/mod.rs

@@ -1120,7 +1120,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 });
                         }
                         if let Some(clone_trait) = tcx.lang_items().clone_trait()
-                            && let trait_ref = tcx.mk_trait_ref(clone_trait, [ty])
+                            && let trait_ref = ty::TraitRef::new(tcx, clone_trait, [ty])
                             && let o = Obligation::new(
                                 tcx,
                                 ObligationCause::dummy(),

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -538,7 +538,8 @@ 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 =
+                ty::TraitRef::from_lang_item(tcx, LangItem::Copy, self.last_span, [place_ty.ty]);
 
             // To have a `Copy` operand, the type `T` of the
             // value must be `Copy`. Note that we prove that `T: Copy`,
@@ -1237,8 +1238,12 @@ 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]);
+                    let trait_ref = ty::TraitRef::from_lang_item(
+                        tcx,
+                        LangItem::Sized,
+                        self.last_span,
+                        [place_ty],
+                    );
                     self.prove_trait_ref(
                         trait_ref,
                         location.to_locations(),
@@ -1810,7 +1815,8 @@ 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 =
+                                ty::TraitRef::from_lang_item(tcx, LangItem::Copy, span, [ty]);
 
                             self.prove_trait_ref(
                                 trait_ref,
@@ -1823,7 +1829,7 @@ 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 = ty::TraitRef::from_lang_item(tcx, LangItem::Sized, span, [ty]);
 
                 self.prove_trait_ref(
                     trait_ref,
@@ -1835,7 +1841,7 @@ 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 = ty::TraitRef::from_lang_item(tcx, LangItem::Sized, span, [*ty]);
 
                 self.prove_trait_ref(
                     trait_ref,
@@ -1932,9 +1938,12 @@ 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]);
+                        let trait_ref = ty::TraitRef::from_lang_item(
+                            tcx,
+                            LangItem::CoerceUnsized,
+                            span,
+                            [op.ty(body, tcx), ty],
+                        );
 
                         self.prove_trait_ref(
                             trait_ref,

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

@@ -157,7 +157,7 @@ impl Qualif for NeedsNonConstDrop {
             cx.tcx,
             ObligationCause::dummy_with_span(cx.body.span),
             cx.param_env,
-            ty::Binder::dummy(cx.tcx.at(cx.body.span).mk_trait_ref(LangItem::Destruct, [ty]))
+            ty::TraitRef::from_lang_item(cx.tcx, LangItem::Destruct, cx.body.span, [ty])
                 .with_constness(ty::BoundConstness::ConstIfConst),
         );
 

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -694,7 +694,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         let assoc_bindings = self.create_assoc_bindings_for_generic_args(args);
 
         let poly_trait_ref =
-            ty::Binder::bind_with_vars(tcx.mk_trait_ref(trait_def_id, substs), bound_vars);
+            ty::Binder::bind_with_vars(ty::TraitRef::new(tcx, trait_def_id, substs), bound_vars);
 
         debug!(?poly_trait_ref, ?assoc_bindings);
         bounds.push_trait_bound(tcx, poly_trait_ref, span, constness, polarity);
@@ -846,7 +846,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         if let Some(b) = trait_segment.args().bindings.first() {
             prohibit_assoc_ty_binding(self.tcx(), b.span, Some((trait_segment, span)));
         }
-        self.tcx().mk_trait_ref(trait_def_id, substs)
+        ty::TraitRef::new(self.tcx(), trait_def_id, substs)
     }
 
     #[instrument(level = "debug", skip(self, span))]

compiler/rustc_hir_analysis/src/autoderef.rs

@@ -123,7 +123,7 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
         let tcx = self.infcx.tcx;
 
         // <ty as Deref>
-        let trait_ref = tcx.mk_trait_ref(tcx.lang_items().deref_trait()?, [ty]);
+        let trait_ref = ty::TraitRef::new(tcx, tcx.lang_items().deref_trait()?, [ty]);
 
         let cause = traits::ObligationCause::misc(self.span, self.body_id);
 

compiler/rustc_hir_analysis/src/bounds.rs

@@ -63,7 +63,7 @@ impl<'tcx> Bounds<'tcx> {
 
     pub fn push_sized(&mut self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, span: Span) {
         let sized_def_id = tcx.require_lang_item(LangItem::Sized, Some(span));
-        let trait_ref = ty::Binder::dummy(tcx.mk_trait_ref(sized_def_id, [ty]));
+        let trait_ref = ty::TraitRef::new(tcx, sized_def_id, [ty]);
         // Preferable to put this obligation first, since we report better errors for sized ambiguity.
         self.predicates.insert(0, (trait_ref.without_const().to_predicate(tcx), span));
     }

compiler/rustc_hir_analysis/src/check/check.rs

@@ -536,7 +536,7 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
                             tcx,
                             assoc_item,
                             assoc_item,
-                            tcx.mk_trait_ref(id.owner_id.to_def_id(), trait_substs),
+                            ty::TraitRef::new(tcx, id.owner_id.to_def_id(), trait_substs),
                         );
                     }
                     _ => {}

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1779,7 +1779,7 @@ 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::TraitRef::new(tcx, receiver_trait_def_id, [receiver_ty]);
 
     let obligation = traits::Obligation::new(tcx, cause, wfcx.param_env, trait_ref);
 

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -265,10 +265,11 @@ fn visit_implementation_of_dispatch_from_dyn(tcx: TyCtxt<'_>, impl_did: LocalDef
                         tcx,
                         cause.clone(),
                         param_env,
-                        ty::Binder::dummy(tcx.mk_trait_ref(
+                        ty::TraitRef::new(
+                            tcx,
                             dispatch_from_dyn_trait,
                             [field.ty(tcx, substs_a), field.ty(tcx, substs_b)],
-                        )),
+                        ),
                     ));
                 }
                 let errors = ocx.select_all_or_error();
@@ -504,8 +505,12 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: LocalDefId) -> Coe
     // Register an obligation for `A: Trait<B>`.
     let ocx = ObligationCtxt::new(&infcx);
     let cause = traits::ObligationCause::misc(span, impl_did);
-    let obligation =
-        Obligation::new(tcx, cause, param_env, tcx.mk_trait_ref(trait_def_id, [source, target]));
+    let obligation = Obligation::new(
+        tcx,
+        cause,
+        param_env,
+        ty::TraitRef::new(tcx, trait_def_id, [source, target]),
+    );
     ocx.register_obligation(obligation);
     let errors = ocx.select_all_or_error();
     if !errors.is_empty() {

compiler/rustc_hir_typeck/src/coercion.rs

@@ -601,7 +601,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             self.tcx,
             cause,
             self.fcx.param_env,
-            self.tcx.mk_trait_ref(coerce_unsized_did, [coerce_source, coerce_target])
+            ty::TraitRef::new(self.tcx, coerce_unsized_did, [coerce_source, coerce_target])
         )];
 
         let mut has_unsized_tuple_coercion = false;
@@ -764,8 +764,11 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             self.tcx,
             self.cause.clone(),
             self.param_env,
-            ty::Binder::dummy(
-                self.tcx.at(self.cause.span).mk_trait_ref(hir::LangItem::PointerLike, [a]),
+            ty::TraitRef::from_lang_item(
+                self.tcx,
+                hir::LangItem::PointerLike,
+                self.cause.span,
+                [a],
             ),
         ));
 

compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs

@@ -481,7 +481,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // For the purposes of this function, we hope that it is a `struct` type, and that our current `expr` is a literal of
         // that struct type.
         let impl_trait_self_ref = if self.tcx.is_trait_alias(obligation.impl_or_alias_def_id) {
-            self.tcx.mk_trait_ref(
+            ty::TraitRef::new(
+                self.tcx,
                 obligation.impl_or_alias_def_id,
                 ty::InternalSubsts::identity_for_item(self.tcx, obligation.impl_or_alias_def_id),
             )

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -1895,7 +1895,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 _ => {
                     // Look for a user-provided impl of a `Fn` trait, and point to it.
                     let new_def_id = self.probe(|_| {
-                        let trait_ref = self.tcx.mk_trait_ref(
+                        let trait_ref = ty::TraitRef::new(self.tcx,
                             call_kind.to_def_id(self.tcx),
                             [
                                 callee_ty,

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1096,10 +1096,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.tcx,
                 self.misc(expr.span),
                 self.param_env,
-                ty::Binder::dummy(self.tcx.mk_trait_ref(
+                ty::TraitRef::new(self.tcx,
                     into_def_id,
                     [expr_ty, expected_ty]
-                )),
+                ),
             ))
         {
             let sugg = if expr.precedence().order() >= PREC_POSTFIX {
@@ -1438,7 +1438,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             && !results.expr_adjustments(callee_expr).iter().any(|adj| matches!(adj.kind, ty::adjustment::Adjust::Deref(..)))
             // Check that we're in fact trying to clone into the expected type
             && self.can_coerce(*pointee_ty, expected_ty)
-            && let trait_ref = ty::Binder::dummy(self.tcx.mk_trait_ref(clone_trait_did, [expected_ty]))
+            && let trait_ref = ty::TraitRef::new(self.tcx, clone_trait_did, [expected_ty])
             // And the expected type doesn't implement `Clone`
             && !self.predicate_must_hold_considering_regions(&traits::Obligation::new(
                 self.tcx,

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -316,7 +316,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.var_for_def(cause.span, param)
         });
 
-        let trait_ref = self.tcx.mk_trait_ref(trait_def_id, substs);
+        let trait_ref = ty::TraitRef::new(self.tcx, trait_def_id, substs);
 
         // Construct an obligation
         let poly_trait_ref = ty::Binder::dummy(trait_ref);

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -954,7 +954,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
     ) {
         debug!("assemble_extension_candidates_for_trait(trait_def_id={:?})", trait_def_id);
         let trait_substs = self.fresh_item_substs(trait_def_id);
-        let trait_ref = self.tcx.mk_trait_ref(trait_def_id, trait_substs);
+        let trait_ref = ty::TraitRef::new(self.tcx, trait_def_id, trait_substs);
 
         if self.tcx.is_trait_alias(trait_def_id) {
             // For trait aliases, recursively assume all explicitly named traits are relevant

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -72,7 +72,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.autoderef(span, ty).any(|(ty, _)| {
                     info!("check deref {:?} impl FnOnce", ty);
                     self.probe(|_| {
-                        let trait_ref = tcx.mk_trait_ref(
+                        let trait_ref = ty::TraitRef::new(
+                            tcx,
                             fn_once,
                             [
                                 ty,

compiler/rustc_infer/src/infer/error_reporting/nice_region_error/placeholder_error.rs

@@ -261,11 +261,16 @@ impl<'tcx> NiceRegionError<'_, 'tcx> {
                 (false, None, None, Some(span), String::new())
             };
 
-        let expected_trait_ref = self
-            .cx
-            .resolve_vars_if_possible(self.cx.tcx.mk_trait_ref(trait_def_id, expected_substs));
-        let actual_trait_ref =
-            self.cx.resolve_vars_if_possible(self.cx.tcx.mk_trait_ref(trait_def_id, actual_substs));
+        let expected_trait_ref = self.cx.resolve_vars_if_possible(ty::TraitRef::new(
+            self.cx.tcx,
+            trait_def_id,
+            expected_substs,
+        ));
+        let actual_trait_ref = self.cx.resolve_vars_if_possible(ty::TraitRef::new(
+            self.cx.tcx,
+            trait_def_id,
+            actual_substs,
+        ));
 
         // Search the expected and actual trait references to see (a)
         // whether the sub/sup placeholders appear in them (sometimes

compiler/rustc_infer/src/traits/engine.rs

@@ -18,7 +18,7 @@ pub trait TraitEngine<'tcx>: 'tcx {
         def_id: DefId,
         cause: ObligationCause<'tcx>,
     ) {
-        let trait_ref = infcx.tcx.mk_trait_ref(def_id, [ty]);
+        let trait_ref = ty::TraitRef::new(infcx.tcx, def_id, [ty]);
         self.register_predicate_obligation(
             infcx,
             Obligation {

compiler/rustc_middle/src/ty/context.rs

@@ -1838,7 +1838,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     #[inline(always)]
-    fn check_and_mk_substs(
+    pub(crate) fn check_and_mk_substs(
         self,
         _def_id: DefId,
         substs: impl IntoIterator<Item: Into<GenericArg<'tcx>>>,
@@ -2238,15 +2238,6 @@ impl<'tcx> TyCtxt<'tcx> {
         self.mk_substs_from_iter(iter::once(self_ty.into()).chain(rest))
     }
 
-    pub fn mk_trait_ref(
-        self,
-        trait_def_id: DefId,
-        substs: impl IntoIterator<Item: Into<GenericArg<'tcx>>>,
-    ) -> ty::TraitRef<'tcx> {
-        let substs = self.check_and_mk_substs(trait_def_id, substs);
-        ty::TraitRef { def_id: trait_def_id, substs, _use_mk_trait_ref_instead: () }
-    }
-
     pub fn mk_alias_ty(
         self,
         def_id: DefId,
@@ -2441,15 +2432,6 @@ impl<'tcx> TyCtxtAt<'tcx> {
     pub fn ty_error_with_message(self, msg: &str) -> Ty<'tcx> {
         self.tcx.ty_error_with_message(self.span, msg)
     }
-
-    pub fn mk_trait_ref(
-        self,
-        trait_lang_item: LangItem,
-        substs: impl IntoIterator<Item: Into<ty::GenericArg<'tcx>>>,
-    ) -> ty::TraitRef<'tcx> {
-        let trait_def_id = self.require_lang_item(trait_lang_item, Some(self.span));
-        self.tcx.mk_trait_ref(trait_def_id, substs)
-    }
 }
 
 /// Parameter attributes that can only be determined by examining the body of a function instead

compiler/rustc_middle/src/ty/mod.rs

@@ -1210,6 +1210,18 @@ impl<'tcx> ToPredicate<'tcx, PolyTraitPredicate<'tcx>> for Binder<'tcx, TraitRef
     }
 }
 
+impl<'tcx> ToPredicate<'tcx, PolyTraitPredicate<'tcx>> for TraitRef<'tcx> {
+    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> PolyTraitPredicate<'tcx> {
+        ty::Binder::dummy(self).to_predicate(tcx)
+    }
+}
+
+impl<'tcx> ToPredicate<'tcx, PolyTraitPredicate<'tcx>> for TraitPredicate<'tcx> {
+    fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> PolyTraitPredicate<'tcx> {
+        ty::Binder::dummy(self)
+    }
+}
+
 impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         self.map_bound(|p| PredicateKind::Clause(Clause::Trait(p))).to_predicate(tcx)
@@ -1234,6 +1246,12 @@ impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
     }
 }
 
+impl<'tcx> ToPredicate<'tcx> for TraitPredicate<'tcx> {
+    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
+        PredicateKind::Clause(Clause::Trait(self)).to_predicate(tcx)
+    }
+}
+
 impl<'tcx> Predicate<'tcx> {
     pub fn to_opt_poly_trait_pred(self) -> Option<PolyTraitPredicate<'tcx>> {
         let predicate = self.kind();

compiler/rustc_middle/src/ty/print/mod.rs

@@ -169,8 +169,11 @@ pub trait Printer<'tcx>: Sized {
                 self.path_append(
                     |cx: Self| {
                         if trait_qualify_parent {
-                            let trait_ref =
-                                cx.tcx().mk_trait_ref(parent_def_id, parent_substs.iter().copied());
+                            let trait_ref = ty::TraitRef::new(
+                                cx.tcx(),
+                                parent_def_id,
+                                parent_substs.iter().copied(),
+                            );
                             cx.path_qualified(trait_ref.self_ty(), Some(trait_ref))
                         } else {
                             cx.print_def_path(parent_def_id, parent_substs)

compiler/rustc_middle/src/ty/relate.rs

@@ -315,7 +315,7 @@ impl<'tcx> Relate<'tcx> for ty::TraitRef<'tcx> {
             Err(TypeError::Traits(expected_found(relation, a.def_id, b.def_id)))
         } else {
             let substs = relate_substs(relation, a.substs, b.substs)?;
-            Ok(relation.tcx().mk_trait_ref(a.def_id, substs))
+            Ok(ty::TraitRef::new(relation.tcx(), a.def_id, substs))
         }
     }
 }