rust/tests/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr
2023-01-11 09:32:08 +00:00

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error[E0038]: the trait `NotObjectSafe` cannot be made into an object
--> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:21:13
|
LL | fn car() -> dyn NotObjectSafe {
| ^^^^^^^^^^^^^^^^^ `NotObjectSafe` 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/object-unsafe-trait-in-return-position-dyn-trait.rs:3:8
|
LL | trait NotObjectSafe {
| ------------- this trait cannot be made into an object...
LL | fn foo() -> Self;
| ^^^ ...because associated function `foo` has no `self` parameter
help: consider turning `foo` into a method by giving it a `&self` argument
|
LL | fn foo(&self) -> Self;
| +++++
help: alternatively, consider constraining `foo` so it does not apply to trait objects
|
LL | fn foo() -> Self where Self: Sized;
| +++++++++++++++++
error[E0038]: the trait `NotObjectSafe` cannot be made into an object
--> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:28:17
|
LL | fn cat() -> Box<dyn NotObjectSafe> {
| ^^^^^^^^^^^^^^^^^ `NotObjectSafe` 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/object-unsafe-trait-in-return-position-dyn-trait.rs:3:8
|
LL | trait NotObjectSafe {
| ------------- this trait cannot be made into an object...
LL | fn foo() -> Self;
| ^^^ ...because associated function `foo` has no `self` parameter
help: consider turning `foo` into a method by giving it a `&self` argument
|
LL | fn foo(&self) -> Self;
| +++++
help: alternatively, consider constraining `foo` so it does not apply to trait objects
|
LL | fn foo() -> Self where Self: Sized;
| +++++++++++++++++
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0038`.