mirror of
https://github.com/rust-lang/rust
synced 2024-10-14 12:33:57 +00:00
Esteban Küber
parent
b1688b48d2
commit
6b7e6ea590
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@ -78,14 +78,17 @@ fn add_generic_param_suggestion(
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fn maybe_lint_impl_trait(&self, self_ty: &hir::Ty<'_>, diag: &mut Diagnostic) -> bool {
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let tcx = self.tcx();
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let parent_id = tcx.hir().get_parent_item(self_ty.hir_id).def_id;
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let (hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, generics, _), .. })
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| hir::Node::TraitItem(hir::TraitItem {
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kind: hir::TraitItemKind::Fn(sig, _),
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generics,
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..
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})) = tcx.hir_node_by_def_id(parent_id)
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else {
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return false;
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let (sig, generics, owner) = match tcx.hir_node_by_def_id(parent_id) {
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hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, generics, _), .. }) => {
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(sig, generics, None)
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}
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hir::Node::TraitItem(hir::TraitItem {
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kind: hir::TraitItemKind::Fn(sig, _),
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generics,
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owner_id,
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..
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}) => (sig, generics, Some(tcx.parent(owner_id.to_def_id()))),
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_ => return false,
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};
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let Ok(trait_name) = tcx.sess.source_map().span_to_snippet(self_ty.span) else {
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return false;
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@ -94,6 +97,11 @@ fn maybe_lint_impl_trait(&self, self_ty: &hir::Ty<'_>, diag: &mut Diagnostic) ->
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let is_object_safe = match self_ty.kind {
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hir::TyKind::TraitObject(objects, ..) => {
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objects.iter().all(|o| match o.trait_ref.path.res {
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Res::Def(DefKind::Trait, id) if Some(id) == owner => {
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// When we're dealing with a recursive trait, we don't want to downgrade
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// the error, so we consider them to be object safe always. (#119652)
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true
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}
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Res::Def(DefKind::Trait, id) => tcx.check_is_object_safe(id),
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_ => false,
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})
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@ -0,0 +1,19 @@
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// edition:2021
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#![allow(bare_trait_objects)]
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trait A: Sized {
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fn f(a: A) -> A;
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//~^ ERROR trait objects must include the `dyn` keyword
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//~| ERROR trait objects must include the `dyn` keyword
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}
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trait B {
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fn f(a: B) -> B;
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//~^ ERROR trait objects must include the `dyn` keyword
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//~| ERROR trait objects must include the `dyn` keyword
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}
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trait C {
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fn f(&self, a: C) -> C;
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//~^ ERROR trait objects must include the `dyn` keyword
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//~| ERROR trait objects must include the `dyn` keyword
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}
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fn main() {}
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@ -0,0 +1,105 @@
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/object-unsafe-trait-should-use-self-2021-without-dyn.rs:4:13
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LL | fn f(a: A) -> A;
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| ^
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help: use a new generic type parameter, constrained by `A`
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LL | fn f<T: A>(a: T) -> A;
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| ++++++ ~
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help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
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LL | fn f(a: impl A) -> A;
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| ++++
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help: alternatively, use a trait object to accept any type that implements `A`, accessing its methods at runtime using dynamic dispatch
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LL | fn f(a: &dyn A) -> A;
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| ++++
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/object-unsafe-trait-should-use-self-2021-without-dyn.rs:4:19
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LL | fn f(a: A) -> A;
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| ^
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help: use `impl A` to return an opaque type, as long as you return a single underlying type
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LL | fn f(a: A) -> impl A;
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| ++++
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help: alternatively, you can return an owned trait object
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LL | fn f(a: A) -> Box<dyn A>;
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| +++++++ +
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/object-unsafe-trait-should-use-self-2021-without-dyn.rs:9:13
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LL | fn f(a: B) -> B;
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| ^
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help: use a new generic type parameter, constrained by `B`
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LL | fn f<T: B>(a: T) -> B;
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| ++++++ ~
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help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
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LL | fn f(a: impl B) -> B;
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| ++++
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help: alternatively, use a trait object to accept any type that implements `B`, accessing its methods at runtime using dynamic dispatch
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LL | fn f(a: &dyn B) -> B;
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| ++++
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/object-unsafe-trait-should-use-self-2021-without-dyn.rs:9:19
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LL | fn f(a: B) -> B;
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| ^
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help: use `impl B` to return an opaque type, as long as you return a single underlying type
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LL | fn f(a: B) -> impl B;
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| ++++
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help: alternatively, you can return an owned trait object
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LL | fn f(a: B) -> Box<dyn B>;
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| +++++++ +
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/object-unsafe-trait-should-use-self-2021-without-dyn.rs:14:20
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LL | fn f(&self, a: C) -> C;
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| ^
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help: use a new generic type parameter, constrained by `C`
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LL | fn f<T: C>(&self, a: T) -> C;
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| ++++++ ~
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help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
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LL | fn f(&self, a: impl C) -> C;
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| ++++
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help: alternatively, use a trait object to accept any type that implements `C`, accessing its methods at runtime using dynamic dispatch
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LL | fn f(&self, a: &dyn C) -> C;
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| ++++
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/object-unsafe-trait-should-use-self-2021-without-dyn.rs:14:26
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LL | fn f(&self, a: C) -> C;
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| ^
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help: use `impl C` to return an opaque type, as long as you return a single underlying type
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LL | fn f(&self, a: C) -> impl C;
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| ++++
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help: alternatively, you can return an owned trait object
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LL | fn f(&self, a: C) -> Box<dyn C>;
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| +++++++ +
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error: aborting due to 6 previous errors
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For more information about this error, try `rustc --explain E0782`.
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@ -0,0 +1,17 @@
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// edition:2021
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#![allow(bare_trait_objects)]
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trait A: Sized {
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fn f(a: dyn A) -> dyn A;
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//~^ ERROR associated item referring to unboxed trait object for its own trait
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//~| ERROR the trait `A` cannot be made into an object
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}
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trait B {
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fn f(a: dyn B) -> dyn B;
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//~^ ERROR associated item referring to unboxed trait object for its own trait
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//~| ERROR the trait `B` cannot be made into an object
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}
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trait C {
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fn f(&self, a: dyn C) -> dyn C;
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}
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fn main() {}
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@ -0,0 +1,65 @@
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error: associated item referring to unboxed trait object for its own trait
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--> $DIR/object-unsafe-trait-should-use-self-2021.rs:4:13
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LL | trait A: Sized {
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| - in this trait
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LL | fn f(a: dyn A) -> dyn A;
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| ^^^^^ ^^^^^
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help: you might have meant to use `Self` to refer to the implementing type
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LL | fn f(a: Self) -> Self;
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| ~~~~ ~~~~
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error[E0038]: the trait `A` cannot be made into an object
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--> $DIR/object-unsafe-trait-should-use-self-2021.rs:4:13
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LL | fn f(a: dyn A) -> dyn A;
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| ^^^^^ `A` cannot be made into an object
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note: for a trait to be "object safe" 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>
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--> $DIR/object-unsafe-trait-should-use-self-2021.rs:3:10
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LL | trait A: Sized {
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| - ^^^^^ ...because it requires `Self: Sized`
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| |
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| this trait cannot be made into an object...
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error: associated item referring to unboxed trait object for its own trait
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--> $DIR/object-unsafe-trait-should-use-self-2021.rs:9:13
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LL | trait B {
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| - in this trait
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LL | fn f(a: dyn B) -> dyn B;
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| ^^^^^ ^^^^^
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help: you might have meant to use `Self` to refer to the implementing type
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LL | fn f(a: Self) -> Self;
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| ~~~~ ~~~~
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error[E0038]: the trait `B` cannot be made into an object
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--> $DIR/object-unsafe-trait-should-use-self-2021.rs:9:13
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LL | fn f(a: dyn B) -> dyn B;
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| ^^^^^ `B` cannot be made into an object
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note: for a trait to be "object safe" 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>
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--> $DIR/object-unsafe-trait-should-use-self-2021.rs:9:8
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LL | trait B {
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| - this trait cannot be made into an object...
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LL | fn f(a: dyn B) -> dyn B;
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| ^ ...because associated function `f` has no `self` parameter
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help: consider turning `f` into a method by giving it a `&self` argument
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LL | fn f(&self, a: dyn B) -> dyn B;
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| ++++++
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help: alternatively, consider constraining `f` so it does not apply to trait objects
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LL | fn f(a: dyn B) -> dyn B where Self: Sized;
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| +++++++++++++++++
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error: aborting due to 4 previous errors
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For more information about this error, try `rustc --explain E0038`.
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