add Self type into whereclause

compiler/rustc_middle/src/ty/sty.rs

@@ -963,20 +963,13 @@ pub struct ExistentialTraitRef<'tcx> {
     pub substs: SubstsRef<'tcx>,
 }
 
-impl<'tcx> ExistentialTraitRef<'tcx> {
-    pub fn erase_self_ty(
-        tcx: TyCtxt<'tcx>,
-        trait_ref: ty::TraitRef<'tcx>,
-    ) -> ty::ExistentialTraitRef<'tcx> {
-        // Assert there is a Self.
-        trait_ref.substs.type_at(0);
-
-        ty::ExistentialTraitRef {
-            def_id: trait_ref.def_id,
-            substs: tcx.intern_substs(&trait_ref.substs[1..]),
-        }
+impl From<TraitRef<'tcx>> for ExistentialTraitRef<'tcx> {
+    fn from(trait_ref: TraitRef<'tcx>) -> Self {
+        Self { def_id: trait_ref.def_id, substs: trait_ref.substs }
     }
+}
 
+impl<'tcx> ExistentialTraitRef<'tcx> {
     /// Object types don't have a self type specified. Therefore, when
     /// we convert the principal trait-ref into a normal trait-ref,
     /// you must give *some* self type. A common choice is `mk_err()`
@@ -1532,6 +1525,16 @@ pub struct ExistentialProjection<'tcx> {
     pub ty: Ty<'tcx>,
 }
 
+impl From<ty::ProjectionPredicate<'tcx>> for ExistentialProjection<'tcx> {
+    fn from(projection_predicate: ty::ProjectionPredicate<'tcx>) -> Self {
+        Self {
+            item_def_id: projection_predicate.projection_ty.item_def_id,
+            substs: projection_predicate.projection_ty.substs,
+            ty: projection_predicate.ty,
+        }
+    }
+}
+
 pub type PolyExistentialProjection<'tcx> = Binder<'tcx, ExistentialProjection<'tcx>>;
 
 impl<'tcx> ExistentialProjection<'tcx> {
@@ -1562,20 +1565,6 @@ impl<'tcx> ExistentialProjection<'tcx> {
             ty: self.ty,
         }
     }
-
-    pub fn erase_self_ty(
-        tcx: TyCtxt<'tcx>,
-        projection_predicate: ty::ProjectionPredicate<'tcx>,
-    ) -> Self {
-        // Assert there is a Self.
-        projection_predicate.projection_ty.substs.type_at(0);
-
-        Self {
-            item_def_id: projection_predicate.projection_ty.item_def_id,
-            substs: tcx.intern_substs(&projection_predicate.projection_ty.substs[1..]),
-            ty: projection_predicate.ty,
-        }
-    }
 }
 
 impl<'tcx> PolyExistentialProjection<'tcx> {

compiler/rustc_middle/src/ty/vtable.rs

@@ -76,7 +76,6 @@ pub(super) fn vtable_allocation_provider<'tcx>(
     // No need to do any alignment checks on the memory accesses below, because we know the
     // allocation is correctly aligned as we created it above. Also we're only offsetting by
     // multiples of `ptr_align`, which means that it will stay aligned to `ptr_align`.
-
     for (idx, entry) in vtable_entries.iter().enumerate() {
         let idx: u64 = u64::try_from(idx).unwrap();
         let scalar = match entry {
@@ -97,8 +96,7 @@ pub(super) fn vtable_allocation_provider<'tcx>(
                 ScalarMaybeUninit::from_pointer(fn_ptr, &tcx)
             }
             VtblEntry::TraitVPtr(trait_ref) => {
-                let super_trait_ref = trait_ref
-                    .map_bound(|trait_ref| ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref));
+                let super_trait_ref = trait_ref.map_bound(|trait_ref| trait_ref.into());
                 let supertrait_alloc_id = tcx.vtable_allocation((ty, Some(super_trait_ref)));
                 let vptr = Pointer::from(supertrait_alloc_id);
                 ScalarMaybeUninit::from_pointer(vptr, &tcx)

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -675,8 +675,7 @@ fn vtable_entries<'tcx>(
                 entries.extend(COMMON_VTABLE_ENTRIES);
             }
             VtblSegment::TraitOwnEntries { trait_ref, emit_vptr } => {
-                let existential_trait_ref = trait_ref
-                    .map_bound(|trait_ref| ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref));
+                let existential_trait_ref = trait_ref.map_bound(|trait_ref| trait_ref.into());
 
                 // Lookup the shape of vtable for the trait.
                 let own_existential_entries =

compiler/rustc_trait_selection/src/traits/object_safety.rs

@@ -554,9 +554,7 @@ fn object_ty_for_trait<'tcx>(
 
     let trait_ref = ty::TraitRef::identity(tcx, trait_def_id);
 
-    let trait_predicate = trait_ref.map_bound(|trait_ref| {
-        ty::WhereClause::Trait(ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref))
-    });
+    let trait_predicate = trait_ref.map_bound(|trait_ref| ty::WhereClause::Trait(trait_ref.into()));
 
     let mut associated_types = traits::supertraits(tcx, trait_ref)
         .flat_map(|super_trait_ref| {

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -736,9 +736,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 source_trait_ref = principal_a.with_self_ty(tcx, source);
                 upcast_trait_ref = util::supertraits(tcx, source_trait_ref).nth(idx).unwrap();
                 assert_eq!(data_b.principal_def_id(), Some(upcast_trait_ref.def_id()));
-                let existential_predicate = upcast_trait_ref.map_bound(|trait_ref| {
-                    ty::WhereClause::Trait(ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref))
-                });
+                let existential_predicate = upcast_trait_ref
+                    .map_bound(|trait_ref| ty::WhereClause::Trait(trait_ref.into()));
                 let iter = Some(existential_predicate)
                     .into_iter()
                     .chain(

compiler/rustc_trait_selection/src/traits/util.rs

@@ -285,8 +285,7 @@ pub fn upcast_choices(
 /// that come from `trait_ref`, excluding its supertraits. Used in
 /// computing the vtable base for an upcast trait of a trait object.
 pub fn count_own_vtable_entries(tcx: TyCtxt<'tcx>, trait_ref: ty::PolyTraitRef<'tcx>) -> usize {
-    let existential_trait_ref =
-        trait_ref.map_bound(|trait_ref| ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref));
+    let existential_trait_ref = trait_ref.map_bound(|trait_ref| trait_ref.into());
     let existential_trait_ref = tcx.erase_regions(existential_trait_ref);
     tcx.own_existential_vtable_entries(existential_trait_ref).len()
 }
@@ -299,9 +298,7 @@ pub fn get_vtable_index_of_object_method<N>(
     object: &super::ImplSourceObjectData<'tcx, N>,
     method_def_id: DefId,
 ) -> usize {
-    let existential_trait_ref = object
-        .upcast_trait_ref
-        .map_bound(|trait_ref| ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref));
+    let existential_trait_ref = object.upcast_trait_ref.map_bound(|trait_ref| trait_ref.into());
     let existential_trait_ref = tcx.erase_regions(existential_trait_ref);
     // Count number of methods preceding the one we are selecting and
     // add them to the total offset.

compiler/rustc_typeck/src/astconv/mod.rs

@@ -1458,7 +1458,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         ),
                     );
                 }
-                ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref)
+                trait_ref.into()
             })
         });
         let existential_projections = bounds.projection_bounds.iter().map(|(bound, _)| {
@@ -1469,7 +1469,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         &format!("trait_ref_to_existential called on {:?} with non-dummy Self", b),
                     );
                 }
-                ty::ExistentialProjection::erase_self_ty(tcx, b)
+                b.into()
             })
         });