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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.
35 lines
1.6 KiB
Plaintext
35 lines
1.6 KiB
Plaintext
error[E0038]: the trait `Foo` cannot be made into an object
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--> $DIR/issue-38604.rs:14:13
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LL | let _f: Box<dyn Foo> =
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| ^^^^^^^^^^^^ `Foo` 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/issue-38604.rs:2:22
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LL | trait Foo where u32: Q<Self> {
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| --- ^^^^^^^ ...because it uses `Self` as a type parameter
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| this trait cannot be made into an object...
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= help: only type `()` implements the trait, consider using it directly instead
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error[E0038]: the trait `Foo` cannot be made into an object
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--> $DIR/issue-38604.rs:15:9
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LL | Box::new(());
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| ^^^^^^^^^^^^ `Foo` 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/issue-38604.rs:2:22
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LL | trait Foo where u32: Q<Self> {
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| --- ^^^^^^^ ...because it uses `Self` as a type parameter
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| this trait cannot be made into an object...
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= help: only type `()` implements the trait, consider using it directly instead
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= note: required for the cast from `Box<()>` to `Box<dyn Foo>`
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0038`.
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