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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: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `NotObjectSafe` for this new enum and using it instead:
A
B
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:29:17
|
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: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `NotObjectSafe` for this new enum and using it instead:
A
B
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[E0746]: return type cannot have an unboxed trait object
--> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:21:13
|
LL | fn car() -> dyn NotObjectSafe {
| ^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
|
help: return an `impl Trait` instead of a `dyn Trait`, if all returned values are the same type
|
LL | fn car() -> impl NotObjectSafe {
| ~~~~
help: box the return type, and wrap all of the returned values in `Box::new`
|
LL ~ fn car() -> Box<dyn NotObjectSafe> {
LL |
LL | if true {
LL ~ return Box::new(A);
LL | }
LL ~ Box::new(B)
|
error[E0038]: the trait `NotObjectSafe` cannot be made into an object
--> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:31:16
|
LL | return Box::new(A);
| ^^^^^^^^^^^ `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: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `NotObjectSafe` for this new enum and using it instead:
A
B
= note: required for the cast from `Box<A>` to `Box<(dyn NotObjectSafe + 'static)>`
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:33:5
|
LL | Box::new(B)
| ^^^^^^^^^^^ `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: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `NotObjectSafe` for this new enum and using it instead:
A
B
= note: required for the cast from `Box<B>` to `Box<(dyn NotObjectSafe + 'static)>`
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 5 previous errors
Some errors have detailed explanations: E0038, E0746.
For more information about an error, try `rustc --explain E0038`.
|
