Rollup merge of #131475 - fmease:compiler-mv-obj-safe-dyn-compat-2, r…

…=jieyouxu

Compiler & its UI tests: Rename remaining occurrences of "object safe" to "dyn compatible"

Follow-up to #130826.
Part of #130852.

1. 1st commit: Fix stupid oversights. Should've been part of #130826.
2. 2nd commit: Rename the unstable feature `object_safe_for_dispatch` to `dyn_compatible_for_dispatch`. Might not be worth the churn, you decide.
3. 3rd commit: Apply the renaming to all UI tests (contents and paths).

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.*"]`.
@@ -546,13 +554,6 @@ 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

@@ -777,6 +777,7 @@ 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

@@ -1,12 +1,8 @@
-//! "Object safety" refers to the ability for a trait to be converted
-//! to an object. In general, traits may only be converted to an
-//! object if all of their methods meet certain criteria. In particular,
-//! they must:
+//! "Dyn-compatibility"[^1] refers to the ability for a trait to be converted
+//! to a trait object. In general, traits may only be converted to a trait
+//! object if certain criteria are met.
 //!
-//!   - have a suitable receiver from which we can extract a vtable and coerce to a "thin" version
-//!     that doesn't contain the vtable;
-//!   - not reference the erased type `Self` except for in this receiver;
-//!   - not have generic type parameters.
+//! [^1]: Formerly known as "object safety".
 
 use std::iter;
 use std::ops::ControlFlow;
@@ -506,8 +502,8 @@ fn virtual_call_violations_for_method<'tcx>(
 
 /// This code checks that `receiver_is_dispatchable` is correctly implemented.
 ///
-/// This check is outlined from the object safety check to avoid cycles with
-/// layout computation, which relies on knowing whether methods are object safe.
+/// This check is outlined from the dyn-compatibility check to avoid cycles with
+/// layout computation, which relies on knowing whether methods are dyn-compatible.
 fn check_receiver_correct<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, method: ty::AssocItem) {
     if !is_vtable_safe_method(tcx, trait_def_id, method) {
         return;
@@ -643,8 +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 object safe, 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`.
@@ -678,7 +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"));
@@ -865,7 +861,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for IllegalSelfTypeVisitor<'tcx> {
     }
 
     fn visit_const(&mut self, ct: ty::Const<'tcx>) -> Self::Result {
-        // Constants can only influence object safety if they are generic and reference `Self`.
+        // Constants can only influence dyn-compatibility if they are generic and reference `Self`.
         // This is only possible for unevaluated constants, so we walk these here.
         self.tcx.expand_abstract_consts(ct).super_visit_with(self)
     }

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() {

src/tools/tidy/src/issues.txt

@@ -3172,10 +3172,6 @@ ui/nll/user-annotations/issue-55241.rs
 ui/nll/user-annotations/issue-55748-pat-types-constrain-bindings.rs
 ui/nll/user-annotations/issue-57731-ascibed-coupled-types.rs
 ui/numbers-arithmetic/issue-8460.rs
-ui/object-safety/issue-102762.rs
-ui/object-safety/issue-102933.rs
-ui/object-safety/issue-106247.rs
-ui/object-safety/issue-19538.rs
 ui/on-unimplemented/issue-104140.rs
 ui/or-patterns/issue-64879-trailing-before-guard.rs
 ui/or-patterns/issue-67514-irrefutable-param.rs

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/allocator/dyn-compatible.rs

@@ -0,0 +1,13 @@
+//@ run-pass
+
+// Check that `Allocator` is dyn-compatible, this allows for polymorphic allocators
+
+#![feature(allocator_api)]
+
+use std::alloc::{Allocator, System};
+
+fn ensure_dyn_compatible(_: &dyn Allocator) {}
+
+fn main() {
+    ensure_dyn_compatible(&System);
+}

tests/ui/associated-type-bounds/entails-sized-object-safety.rs → tests/ui/associated-type-bounds/entails-sized-dyn-compatibility.rs

@@ -4,21 +4,21 @@ trait Tr1: Sized { type As1; }
 trait Tr2<'a>: Sized { type As2; }
 
 trait ObjTr1 { fn foo() -> Self where Self: Tr1<As1: Copy>; }
-fn _assert_obj_safe_1(_: Box<dyn ObjTr1>) {}
+fn _assert_dyn_compat_1(_: Box<dyn ObjTr1>) {}
 
 trait ObjTr2 { fn foo() -> Self where Self: Tr1<As1: 'static>; }
-fn _assert_obj_safe_2(_: Box<dyn ObjTr2>) {}
+fn _assert_dyn_compat_2(_: Box<dyn ObjTr2>) {}
 
 trait ObjTr3 { fn foo() -> Self where Self: Tr1<As1: Into<u8> + 'static + Copy>; }
-fn _assert_obj_safe_3(_: Box<dyn ObjTr3>) {}
+fn _assert_dyn_compat_3(_: Box<dyn ObjTr3>) {}
 
 trait ObjTr4 { fn foo() -> Self where Self: Tr1<As1: for<'a> Tr2<'a>>; }
-fn _assert_obj_safe_4(_: Box<dyn ObjTr4>) {}
+fn _assert_dyn_compat_4(_: Box<dyn ObjTr4>) {}
 
 trait ObjTr5 { fn foo() -> Self where for<'a> Self: Tr1<As1: Tr2<'a>>; }
-fn _assert_obj_safe_5(_: Box<dyn ObjTr5>) {}
+fn _assert_dyn_compat_5(_: Box<dyn ObjTr5>) {}
 
 trait ObjTr6 { fn foo() -> Self where Self: for<'a> Tr1<As1: Tr2<'a, As2: for<'b> Tr2<'b>>>; }
-fn _assert_obj_safe_6(_: Box<dyn ObjTr6>) {}
+fn _assert_dyn_compat_6(_: Box<dyn ObjTr6>) {}
 
 fn main() {}

tests/ui/async-await/in-trait/object-safety.stderr → tests/ui/async-await/in-trait/dyn-compatibility.stderr

@@ -1,11 +1,11 @@
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety.rs:9:12
+  --> $DIR/dyn-compatibility.rs:9:12
    |
 LL |     let x: &dyn Foo = todo!();
    |            ^^^^^^^^ `Foo` 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/object-safety.rs:5:14
+  --> $DIR/dyn-compatibility.rs:5:14
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...

tests/ui/coherence/coherence-impl-trait-for-trait-object-safe.rs → tests/ui/coherence/coherence-impl-trait-for-trait-dyn-compatible.rs

@@ -1,10 +1,10 @@
 // Test that we give suitable error messages when the user attempts to
 // impl a trait `Trait` for its own object type.
 
-// If the trait is not object-safe, we give a more tailored message
+// If the trait is dyn-incompatible, we give a more tailored message
 // because we're such schnuckels:
-trait NotObjectSafe { fn eq(&self, other: Self); }
-impl NotObjectSafe for dyn NotObjectSafe { }
+trait DynIncompatible { fn eq(&self, other: Self); }
+impl DynIncompatible for dyn DynIncompatible { }
 //~^ ERROR E0038
 //~| ERROR E0046
 

tests/ui/coherence/coherence-impl-trait-for-trait-dyn-compatible.stderr

@@ -0,0 +1,27 @@
+error[E0038]: the trait `DynIncompatible` cannot be made into an object
+  --> $DIR/coherence-impl-trait-for-trait-dyn-compatible.rs:7:26
+   |
+LL | impl DynIncompatible for dyn DynIncompatible { }
+   |                          ^^^^^^^^^^^^^^^^^^^ `DynIncompatible` 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/coherence-impl-trait-for-trait-dyn-compatible.rs:6:45
+   |
+LL | trait DynIncompatible { fn eq(&self, other: Self); }
+   |       ---------------                       ^^^^ ...because method `eq` references the `Self` type in this parameter
+   |       |
+   |       this trait cannot be made into an object...
+   = help: consider moving `eq` to another trait
+
+error[E0046]: not all trait items implemented, missing: `eq`
+  --> $DIR/coherence-impl-trait-for-trait-dyn-compatible.rs:7:1
+   |
+LL | trait DynIncompatible { fn eq(&self, other: Self); }
+   |                         -------------------------- `eq` from trait
+LL | impl DynIncompatible for dyn DynIncompatible { }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `eq` in implementation
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0038, E0046.
+For more information about an error, try `rustc --explain E0038`.

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/const-generics/adt_const_params/const_param_ty_object_safety.stderr → tests/ui/const-generics/adt_const_params/const_param_ty_dyn_compatibility.stderr

@@ -1,5 +1,5 @@
 error[E0038]: the trait `ConstParamTy_` cannot be made into an object
-  --> $DIR/const_param_ty_object_safety.rs:6:12
+  --> $DIR/const_param_ty_dyn_compatibility.rs:6:12
    |
 LL | fn foo(a: &dyn ConstParamTy_) {}
    |            ^^^^^^^^^^^^^^^^^ `ConstParamTy_` cannot be made into an object
@@ -14,7 +14,7 @@ LL | fn foo(a: &impl ConstParamTy_) {}
    |            ~~~~
 
 error[E0038]: the trait `UnsizedConstParamTy` cannot be made into an object
-  --> $DIR/const_param_ty_object_safety.rs:9:12
+  --> $DIR/const_param_ty_dyn_compatibility.rs:9:12
    |
 LL | fn bar(a: &dyn UnsizedConstParamTy) {}
    |            ^^^^^^^^^^^^^^^^^^^^^^^ `UnsizedConstParamTy` cannot be made into an object

tests/ui/const-generics/generic_const_exprs/object-safety-err-ret.stderr → tests/ui/const-generics/generic_const_exprs/dyn-compatibility-err-ret.stderr

@@ -1,11 +1,11 @@
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety-err-ret.rs:17:16
+  --> $DIR/dyn-compatibility-err-ret.rs:17:16
    |
 LL | fn use_dyn(v: &dyn Foo) {
    |                ^^^^^^^ `Foo` 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/object-safety-err-ret.rs:8:8
+  --> $DIR/dyn-compatibility-err-ret.rs:8:8
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...
@@ -17,13 +17,13 @@ LL |     fn test(&self) -> [u8; bar::<Self>()];
    = help: only type `()` implements the trait, consider using it directly instead
 
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety-err-ret.rs:18:5
+  --> $DIR/dyn-compatibility-err-ret.rs:18:5
    |
 LL |     v.test();
    |     ^^^^^^^^ `Foo` 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/object-safety-err-ret.rs:8:8
+  --> $DIR/dyn-compatibility-err-ret.rs:8:8
    |
 LL | trait Foo {
    |       --- this trait cannot be made into an object...