rust/tests/ui/object-safety/object-safety-supertrait-mentions-Self.stderr

43 lines
1.7 KiB
Plaintext

error[E0277]: the size for values of type `Self` cannot be known at compilation time
--> $DIR/object-safety-supertrait-mentions-Self.rs:8:13
|
LL | trait Baz : Bar<Self> {
| ^^^^^^^^^ doesn't have a size known at compile-time
|
note: required by an implicit `Sized` bound in `Bar`
--> $DIR/object-safety-supertrait-mentions-Self.rs:4:11
|
LL | trait Bar<T> {
| ^ required by the implicit `Sized` requirement on this type parameter in `Bar`
help: consider further restricting `Self`
|
LL | trait Baz : Bar<Self> + Sized {
| +++++++
help: consider relaxing the implicit `Sized` restriction
|
LL | trait Bar<T: ?Sized> {
| ++++++++
error[E0038]: the trait `Baz` cannot be made into an object
--> $DIR/object-safety-supertrait-mentions-Self.rs:16:31
|
LL | fn make_baz<T:Baz>(t: &T) -> &dyn Baz {
| ^^^^^^^ `Baz` 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-safety-supertrait-mentions-Self.rs:8:13
|
LL | trait Baz : Bar<Self> {
| --- ^^^^^^^^^ ...because it uses `Self` as a type parameter
| |
| this trait cannot be made into an object...
help: consider using an opaque type instead
|
LL | fn make_baz<T:Baz>(t: &T) -> &impl Baz {
| ~~~~
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0038, E0277.
For more information about an error, try `rustc --explain E0038`.