rust/tests/ui/wf/wf-convert-unsafe-trait-obj-box.stderr
Esteban Küber 8c04999226 On object safety error, mention new enum as alternative
When we encounter a `dyn Trait` that isn't object safe, look for its
implementors. If there's one, mention using it directly If there are
less than 9, mention the possibility of creating a new enum and using
that instead.

Account for object unsafe `impl Trait on dyn Trait {}`.  Make a
distinction between public and sealed traits.

Fix #80194.
2023-10-29 23:55:46 +00:00

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error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:16:33
|
LL | let t_box: Box<dyn Trait> = Box::new(S);
| ^^^^^^^^^^^ `Trait` cannot be made into an object
|
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>
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:6:14
|
LL | trait Trait: Sized {}
| ----- ^^^^^ ...because it requires `Self: Sized`
| |
| this trait cannot be made into an object...
= help: only type `S` implements the trait, consider using it directly instead
= note: required for the cast from `Box<S>` to `Box<dyn Trait>`
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:17:15
|
LL | takes_box(Box::new(S));
| ^^^^^^^^^^^ `Trait` cannot be made into an object
|
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>
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:6:14
|
LL | trait Trait: Sized {}
| ----- ^^^^^ ...because it requires `Self: Sized`
| |
| this trait cannot be made into an object...
= help: only type `S` implements the trait, consider using it directly instead
= note: required for the cast from `Box<S>` to `Box<(dyn Trait + 'static)>`
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:15:5
|
LL | Box::new(S) as Box<dyn Trait>;
| ^^^^^^^^^^^ `Trait` cannot be made into an object
|
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>
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:6:14
|
LL | trait Trait: Sized {}
| ----- ^^^^^ ...because it requires `Self: Sized`
| |
| this trait cannot be made into an object...
= help: only type `S` implements the trait, consider using it directly instead
= note: required for the cast from `Box<S>` to `Box<dyn Trait>`
error: aborting due to 3 previous errors
For more information about this error, try `rustc --explain E0038`.