mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-24 07:44:10 +00:00
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.
51 lines
2.1 KiB
Plaintext
51 lines
2.1 KiB
Plaintext
error[E0038]: the trait `Tr` cannot be made into an object
|
|
--> $DIR/safety.rs:15:22
|
|
|
|
|
LL | let _: &dyn Tr = &St;
|
|
| ^^^ `Tr` 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/safety.rs:4:8
|
|
|
|
|
LL | trait Tr {
|
|
| -- this trait cannot be made into an object...
|
|
LL | fn foo();
|
|
| ^^^ ...because associated function `foo` has no `self` parameter
|
|
= help: only type `St` implements the trait, consider using it directly instead
|
|
= note: required for the cast from `&St` to `&dyn Tr`
|
|
help: consider turning `foo` into a method by giving it a `&self` argument
|
|
|
|
|
LL | fn foo(&self);
|
|
| +++++
|
|
help: alternatively, consider constraining `foo` so it does not apply to trait objects
|
|
|
|
|
LL | fn foo() where Self: Sized;
|
|
| +++++++++++++++++
|
|
|
|
error[E0038]: the trait `Tr` cannot be made into an object
|
|
--> $DIR/safety.rs:15:12
|
|
|
|
|
LL | let _: &dyn Tr = &St;
|
|
| ^^^^^^^ `Tr` 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/safety.rs:4:8
|
|
|
|
|
LL | trait Tr {
|
|
| -- this trait cannot be made into an object...
|
|
LL | fn foo();
|
|
| ^^^ ...because associated function `foo` has no `self` parameter
|
|
= help: only type `St` implements the trait, consider using it directly instead
|
|
help: consider turning `foo` into a method by giving it a `&self` argument
|
|
|
|
|
LL | fn foo(&self);
|
|
| +++++
|
|
help: alternatively, consider constraining `foo` so it does not apply to trait objects
|
|
|
|
|
LL | fn foo() where Self: Sized;
|
|
| +++++++++++++++++
|
|
|
|
error: aborting due to 2 previous errors
|
|
|
|
For more information about this error, try `rustc --explain E0038`.
|