8c04999226
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.
52 lines
2.5 KiB
Plaintext
52 lines
2.5 KiB
Plaintext
error[E0038]: the trait `Trait` cannot be made into an object
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--> $DIR/wf-convert-unsafe-trait-obj-box.rs:16:33
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LL | let t_box: Box<dyn Trait> = Box::new(S);
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| ^^^^^^^^^^^ `Trait` 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/wf-convert-unsafe-trait-obj-box.rs:6:14
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LL | trait Trait: Sized {}
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| ----- ^^^^^ ...because it requires `Self: Sized`
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| this trait cannot be made into an object...
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= help: only type `S` implements the trait, consider using it directly instead
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= note: required for the cast from `Box<S>` to `Box<dyn Trait>`
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error[E0038]: the trait `Trait` cannot be made into an object
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--> $DIR/wf-convert-unsafe-trait-obj-box.rs:17:15
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LL | takes_box(Box::new(S));
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| ^^^^^^^^^^^ `Trait` 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/wf-convert-unsafe-trait-obj-box.rs:6:14
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LL | trait Trait: Sized {}
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| ----- ^^^^^ ...because it requires `Self: Sized`
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| this trait cannot be made into an object...
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= help: only type `S` implements the trait, consider using it directly instead
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= note: required for the cast from `Box<S>` to `Box<(dyn Trait + 'static)>`
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error[E0038]: the trait `Trait` cannot be made into an object
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--> $DIR/wf-convert-unsafe-trait-obj-box.rs:15:5
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LL | Box::new(S) as Box<dyn Trait>;
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| ^^^^^^^^^^^ `Trait` 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/wf-convert-unsafe-trait-obj-box.rs:6:14
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LL | trait Trait: Sized {}
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| ----- ^^^^^ ...because it requires `Self: Sized`
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| this trait cannot be made into an object...
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= help: only type `S` implements the trait, consider using it directly instead
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= note: required for the cast from `Box<S>` to `Box<dyn Trait>`
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error: aborting due to 3 previous errors
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For more information about this error, try `rustc --explain E0038`.
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