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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.
39 lines
1.7 KiB
Plaintext
39 lines
1.7 KiB
Plaintext
error[E0038]: the trait `Bar` cannot be made into an object
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--> $DIR/issue-19538.rs:17:15
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LL | let test: &mut dyn Bar = &mut thing;
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| ^^^^^^^^^^^^ `Bar` 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-19538.rs:2:8
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LL | fn foo<T>(&self, val: T);
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| ^^^ ...because method `foo` has generic type parameters
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...
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LL | trait Bar: Foo { }
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| --- this trait cannot be made into an object...
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= help: consider moving `foo` to another trait
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= help: only type `Thing` implements the trait, consider using it directly instead
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error[E0038]: the trait `Bar` cannot be made into an object
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--> $DIR/issue-19538.rs:17:30
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LL | let test: &mut dyn Bar = &mut thing;
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| ^^^^^^^^^^ `Bar` 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-19538.rs:2:8
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LL | fn foo<T>(&self, val: T);
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| ^^^ ...because method `foo` has generic type parameters
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...
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LL | trait Bar: Foo { }
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| --- this trait cannot be made into an object...
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= help: consider moving `foo` to another trait
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= help: only type `Thing` implements the trait, consider using it directly instead
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= note: required for the cast from `&mut Thing` to `&mut dyn Bar`
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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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