Rename feature object_safe_for_dispatch to dyn_compatible_for_dispatch

compiler/rustc_feature/src/removed.rs

@@ -154,6 +154,10 @@ declare_features! (
     /// then removed. But there was no utility storing it separately, so now
     /// it's in this list.
     (removed, no_stack_check, "1.0.0", None, None),
+    /// Allows making `dyn Trait` well-formed even if `Trait` is not dyn-compatible (object safe).
+    /// Renamed to `dyn_compatible_for_dispatch`.
+    (removed, object_safe_for_dispatch, "CURRENT_RUSTC_VERSION", Some(43561),
+     Some("renamed to `dyn_compatible_for_dispatch`")),
     /// Allows using `#[on_unimplemented(..)]` on traits.
     /// (Moved to `rustc_attrs`.)
     (removed, on_unimplemented, "1.40.0", None, None),

compiler/rustc_feature/src/unstable.rs

@@ -259,6 +259,14 @@ declare_features! (
     (unstable, doc_notable_trait, "1.52.0", Some(45040)),
     /// Allows using the `may_dangle` attribute (RFC 1327).
     (unstable, dropck_eyepatch, "1.10.0", Some(34761)),
+    /// Allows making `dyn Trait` well-formed even if `Trait` is not dyn-compatible[^1].
+    /// In that case, `dyn Trait: Trait` does not hold. Moreover, coercions and
+    /// casts in safe Rust to `dyn Trait` for such a `Trait` is also forbidden.
+    ///
+    /// Renamed from `object_safe_for_dispatch`.
+    ///
+    /// [^1]: Formerly known as "object safe".
+    (unstable, dyn_compatible_for_dispatch, "CURRENT_RUSTC_VERSION", Some(43561)),
     /// Allows using the `#[fundamental]` attribute.
     (unstable, fundamental, "1.0.0", Some(29635)),
     /// Allows using `#[link_name="llvm.*"]`.
@@ -544,13 +552,6 @@ declare_features! (
     (unstable, non_exhaustive_omitted_patterns_lint, "1.57.0", Some(89554)),
     /// Allows `for<T>` binders in where-clauses
     (incomplete, non_lifetime_binders, "1.69.0", Some(108185)),
-    /// Allows making `dyn Trait` well-formed even if `Trait` is not dyn-compatible[^1].
-    /// In that case, `dyn Trait: Trait` does not hold. Moreover, coercions and
-    /// casts in safe Rust to `dyn Trait` for such a `Trait` is also forbidden.
-    ///
-    /// [^1]: Formerly known as "object safe".
-    // FIXME(dyn_compat_renaming): Rename feature.
-    (unstable, object_safe_for_dispatch, "1.40.0", Some(43561)),
     /// Allows using enums in offset_of!
     (unstable, offset_of_enum, "1.75.0", Some(120141)),
     /// Allows using fields with slice type in offset_of!

compiler/rustc_hir_analysis/src/coherence/mod.rs

@@ -199,7 +199,7 @@ fn check_object_overlap<'tcx>(
         for component_def_id in component_def_ids {
             if !tcx.is_dyn_compatible(component_def_id) {
                 // FIXME(dyn_compat_renaming): Rename test and update comment.
-                // Without the 'object_safe_for_dispatch' feature this is an error
+                // Without the 'dyn_compatible_for_dispatch' feature this is an error
                 // which will be reported by wfcheck. Ignore it here.
                 // This is tested by `coherence-impl-trait-for-trait-object-safe.rs`.
                 // With the feature enabled, the trait is not implemented automatically,

compiler/rustc_span/src/symbol.rs

@@ -776,6 +776,7 @@ symbols! {
         dropck_eyepatch,
         dropck_parametricity,
         dylib,
+        dyn_compatible_for_dispatch,
         dyn_metadata,
         dyn_star,
         dyn_trait,

compiler/rustc_trait_selection/src/traits/dyn_compatibility.rs

@@ -639,8 +639,8 @@ fn object_ty_for_trait<'tcx>(
 /// contained by the trait object, because the object that needs to be coerced is behind
 /// a pointer.
 ///
-/// In practice, we cannot use `dyn Trait` explicitly in the obligation because it would result
-/// in a new check that `Trait` is dyn-compatible, creating a cycle (until object_safe_for_dispatch
+/// In practice, we cannot use `dyn Trait` explicitly in the obligation because it would result in
+/// a new check that `Trait` is dyn-compatible, creating a cycle (until dyn_compatible_for_dispatch
 /// is stabilized, see tracking issue <https://github.com/rust-lang/rust/issues/43561>).
 /// Instead, we fudge a little by introducing a new type parameter `U` such that
 /// `Self: Unsize<U>` and `U: Trait + ?Sized`, and use `U` in place of `dyn Trait`.
@@ -674,7 +674,7 @@ fn receiver_is_dispatchable<'tcx>(
 
     // the type `U` in the query
     // use a bogus type parameter to mimic a forall(U) query using u32::MAX for now.
-    // FIXME(mikeyhew) this is a total hack. Once object_safe_for_dispatch is stabilized, we can
+    // FIXME(mikeyhew) this is a total hack. Once dyn_compatible_for_dispatch is stabilized, we can
     // replace this with `dyn Trait`
     let unsized_self_ty: Ty<'tcx> =
         Ty::new_param(tcx, u32::MAX, Symbol::intern("RustaceansAreAwesome"));

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

@@ -881,7 +881,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                         }
 
                         if let Some(principal) = data.principal() {
-                            if !self.infcx.tcx.features().object_safe_for_dispatch {
+                            if !self.infcx.tcx.features().dyn_compatible_for_dispatch {
                                 principal.with_self_ty(self.tcx(), self_ty)
                             } else if self.tcx().is_dyn_compatible(principal.def_id()) {
                                 principal.with_self_ty(self.tcx(), self_ty)

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -829,7 +829,7 @@ impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for WfPredicates<'a, 'tcx> {
                 // obligations that don't refer to Self and
                 // checking those
 
-                let defer_to_coercion = tcx.features().object_safe_for_dispatch;
+                let defer_to_coercion = tcx.features().dyn_compatible_for_dispatch;
 
                 if !defer_to_coercion {
                     if let Some(principal) = data.principal_def_id() {

tests/crashes/120241-2.rs

@@ -1,6 +1,6 @@
 //@ known-bug: #120241
 //@ edition:2021
-#![feature(object_safe_for_dispatch)]
+#![feature(dyn_compatible_for_dispatch)]
 #![feature(unsized_fn_params)]
 
 fn guard(_s: Copy) -> bool {

tests/crashes/120241.rs

@@ -1,6 +1,6 @@
 //@ known-bug: #120241
 //@ edition:2021
-#![feature(object_safe_for_dispatch)]
+#![feature(dyn_compatible_for_dispatch)]
 
 trait B {
     fn f(a: A) -> A;

tests/crashes/120482.rs

@@ -1,6 +1,6 @@
 //@ known-bug: #120482
 //@ edition:2021
-#![feature(object_safe_for_dispatch)]
+#![feature(dyn_compatible_for_dispatch)]
 
 trait B {
     fn bar(&self, x: &Self);

tests/crashes/125512.rs

@@ -1,6 +1,6 @@
 //@ known-bug: rust-lang/rust#125512
 //@ edition:2021
-#![feature(object_safe_for_dispatch)]
+#![feature(dyn_compatible_for_dispatch)]
 trait B {
     fn f(a: A) -> A;
 }

tests/crashes/128176.rs

@@ -1,7 +1,7 @@
 //@ known-bug: rust-lang/rust#128176
 
 #![feature(generic_const_exprs)]
-#![feature(object_safe_for_dispatch)]
+#![feature(dyn_compatible_for_dispatch)]
 trait X {
     type Y<const N: i16>;
 }

tests/crashes/130521.rs

@@ -1,6 +1,6 @@
 //@ known-bug: #130521
 
-#![feature(object_safe_for_dispatch)]
+#![feature(dyn_compatible_for_dispatch)]
 struct Vtable(dyn Cap);
 
 trait Cap<'a> {}

tests/ui/coherence/coherence-unsafe-trait-object-impl.rs

@@ -1,7 +1,7 @@
 // Check that unsafe trait object do not implement themselves
 // automatically
 
-#![feature(object_safe_for_dispatch)]
+#![feature(dyn_compatible_for_dispatch)]
 
 trait Trait: Sized {
     fn call(&self);

tests/ui/feature-gates/feature-gate-dyn_compatible_for_dispatch.rs

@@ -0,0 +1,41 @@
+// Test that the use of the dyn-incompatible trait objects
+// are gated by the `dyn_compatible_for_dispatch` feature gate.
+
+trait DynIncompatible1: Sized {}
+
+trait DynIncompatible2 {
+    fn static_fn() {}
+}
+
+trait DynIncompatible3 {
+    fn foo<T>(&self);
+}
+
+trait DynIncompatible4 {
+    fn foo(&self, s: &Self);
+}
+
+fn takes_non_object_safe_ref<T>(obj: &dyn DynIncompatible1) {
+    //~^ ERROR E0038
+}
+
+fn return_non_object_safe_ref() -> &'static dyn DynIncompatible2 {
+    //~^ ERROR E0038
+    loop {}
+}
+
+fn takes_non_object_safe_box(obj: Box<dyn DynIncompatible3>) {
+    //~^ ERROR E0038
+}
+
+fn return_non_object_safe_rc() -> std::rc::Rc<dyn DynIncompatible4> {
+    //~^ ERROR E0038
+    loop {}
+}
+
+trait Trait {}
+
+impl Trait for dyn DynIncompatible1 {}
+//~^ ERROR E0038
+
+fn main() {}

tests/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr → tests/ui/feature-gates/feature-gate-dyn_compatible_for_dispatch.stderr

@@ -1,28 +1,28 @@
-error[E0038]: the trait `NonObjectSafe1` cannot be made into an object
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:18:39
+error[E0038]: the trait `DynIncompatible1` cannot be made into an object
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:18:39
    |
-LL | fn takes_non_object_safe_ref<T>(obj: &dyn NonObjectSafe1) {
-   |                                       ^^^^^^^^^^^^^^^^^^ `NonObjectSafe1` cannot be made into an object
+LL | fn takes_non_object_safe_ref<T>(obj: &dyn DynIncompatible1) {
+   |                                       ^^^^^^^^^^^^^^^^^^^^ `DynIncompatible1` cannot be made into an object
    |
 note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:4:23
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:4:25
    |
-LL | trait NonObjectSafe1: Sized {}
-   |       --------------  ^^^^^ ...because it requires `Self: Sized`
+LL | trait DynIncompatible1: Sized {}
+   |       ----------------  ^^^^^ ...because it requires `Self: Sized`
    |       |
    |       this trait cannot be made into an object...
 
-error[E0038]: the trait `NonObjectSafe2` cannot be made into an object
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:22:45
+error[E0038]: the trait `DynIncompatible2` cannot be made into an object
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:22:45
    |
-LL | fn return_non_object_safe_ref() -> &'static dyn NonObjectSafe2 {
-   |                                             ^^^^^^^^^^^^^^^^^^ `NonObjectSafe2` cannot be made into an object
+LL | fn return_non_object_safe_ref() -> &'static dyn DynIncompatible2 {
+   |                                             ^^^^^^^^^^^^^^^^^^^^ `DynIncompatible2` cannot be made into an object
    |
 note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:7:8
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:7:8
    |
-LL | trait NonObjectSafe2 {
-   |       -------------- this trait cannot be made into an object...
+LL | trait DynIncompatible2 {
+   |       ---------------- this trait cannot be made into an object...
 LL |     fn static_fn() {}
    |        ^^^^^^^^^ ...because associated function `static_fn` has no `self` parameter
 help: consider turning `static_fn` into a method by giving it a `&self` argument
@@ -34,47 +34,47 @@ help: alternatively, consider constraining `static_fn` so it does not apply to t
 LL |     fn static_fn() where Self: Sized {}
    |                    +++++++++++++++++
 
-error[E0038]: the trait `NonObjectSafe3` cannot be made into an object
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:27:39
+error[E0038]: the trait `DynIncompatible3` cannot be made into an object
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:27:39
    |
-LL | fn takes_non_object_safe_box(obj: Box<dyn NonObjectSafe3>) {
-   |                                       ^^^^^^^^^^^^^^^^^^ `NonObjectSafe3` cannot be made into an object
+LL | fn takes_non_object_safe_box(obj: Box<dyn DynIncompatible3>) {
+   |                                       ^^^^^^^^^^^^^^^^^^^^ `DynIncompatible3` cannot be made into an object
    |
 note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:11:8
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:11:8
    |
-LL | trait NonObjectSafe3 {
-   |       -------------- this trait cannot be made into an object...
+LL | trait DynIncompatible3 {
+   |       ---------------- this trait cannot be made into an object...
 LL |     fn foo<T>(&self);
    |        ^^^ ...because method `foo` has generic type parameters
    = help: consider moving `foo` to another trait
 
-error[E0038]: the trait `NonObjectSafe4` cannot be made into an object
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:31:47
+error[E0038]: the trait `DynIncompatible4` cannot be made into an object
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:31:47
    |
-LL | fn return_non_object_safe_rc() -> std::rc::Rc<dyn NonObjectSafe4> {
-   |                                               ^^^^^^^^^^^^^^^^^^ `NonObjectSafe4` cannot be made into an object
+LL | fn return_non_object_safe_rc() -> std::rc::Rc<dyn DynIncompatible4> {
+   |                                               ^^^^^^^^^^^^^^^^^^^^ `DynIncompatible4` cannot be made into an object
    |
 note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:15:22
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:15:22
    |
-LL | trait NonObjectSafe4 {
-   |       -------------- this trait cannot be made into an object...
+LL | trait DynIncompatible4 {
+   |       ---------------- this trait cannot be made into an object...
 LL |     fn foo(&self, s: &Self);
    |                      ^^^^^ ...because method `foo` references the `Self` type in this parameter
    = help: consider moving `foo` to another trait
 
-error[E0038]: the trait `NonObjectSafe1` cannot be made into an object
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:38:16
+error[E0038]: the trait `DynIncompatible1` cannot be made into an object
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:38:16
    |
-LL | impl Trait for dyn NonObjectSafe1 {}
-   |                ^^^^^^^^^^^^^^^^^^ `NonObjectSafe1` cannot be made into an object
+LL | impl Trait for dyn DynIncompatible1 {}
+   |                ^^^^^^^^^^^^^^^^^^^^ `DynIncompatible1` cannot be made into an object
    |
 note: for a trait to be "dyn-compatible" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:4:23
+  --> $DIR/feature-gate-dyn_compatible_for_dispatch.rs:4:25
    |
-LL | trait NonObjectSafe1: Sized {}
-   |       --------------  ^^^^^ ...because it requires `Self: Sized`
+LL | trait DynIncompatible1: Sized {}
+   |       ----------------  ^^^^^ ...because it requires `Self: Sized`
    |       |
    |       this trait cannot be made into an object...
 

tests/ui/kindck/kindck-inherited-copy-bound.rs

@@ -1,8 +1,8 @@
 // Test that Copy bounds inherited by trait are checked.
 //
-//@ revisions: curr object_safe_for_dispatch
+//@ revisions: curr dyn_compatible_for_dispatch
 
-#![cfg_attr(object_safe_for_dispatch, feature(object_safe_for_dispatch))]
+#![cfg_attr(dyn_compatible_for_dispatch, feature(dyn_compatible_for_dispatch))]
 
 
 use std::any::Any;
@@ -19,7 +19,7 @@ fn take_param<T:Foo>(foo: &T) { }
 fn a() {
     let x: Box<_> = Box::new(3);
     take_param(&x); //[curr]~ ERROR E0277
-    //[object_safe_for_dispatch]~^ ERROR E0277
+    //[dyn_compatible_for_dispatch]~^ ERROR E0277
 }
 
 fn b() {
@@ -28,7 +28,7 @@ fn b() {
     let z = &x as &dyn Foo;
     //[curr]~^ ERROR E0038
     //[curr]~| ERROR E0038
-    //[object_safe_for_dispatch]~^^^ ERROR E0038
+    //[dyn_compatible_for_dispatch]~^^^ ERROR E0038
 }
 
 fn main() { }

tests/ui/object-safety/object-safety-associated-consts.rs

@@ -1,9 +1,9 @@
 // Check that we correctly prevent users from making trait objects
 // from traits with associated consts.
 //
-//@ revisions: curr object_safe_for_dispatch
+//@ revisions: curr dyn_compatible_for_dispatch
 
-#![cfg_attr(object_safe_for_dispatch, feature(object_safe_for_dispatch))]
+#![cfg_attr(dyn_compatible_for_dispatch, feature(dyn_compatible_for_dispatch))]
 
 trait Bar {
     const X: usize;