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error[E0308]: `match` arms have incompatible types
--> $DIR/wf-unsafe-trait-obj-match.rs:23:17
|
LL | / match opt() {
LL | | Some(()) => &S,
| | -- this is found to be of type `&S`
LL | | None => &R,
| | ^^ expected `&S`, found `&R`
LL | | }
| |_____- `match` arms have incompatible types
|
= note: expected reference `&S`
found reference `&R`
help: consider using a semicolon here, but this will discard any values in the match arms
|
LL | };
| +
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-unsafe-trait-obj-match.rs:26:21
|
LL | Some(()) => &S,
| ^^ `Trait` 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/wf-unsafe-trait-obj-match.rs:6:14
|
LL | trait Trait: Sized {}
| ----- ^^^^^ ...because it requires `Self: Sized`
| |
| this trait cannot be made into an object...
= help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `Trait` for this new enum and using it instead:
S
R
= note: required for the cast from `&S` to `&dyn Trait`
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-unsafe-trait-obj-match.rs:25:25
|
LL | let t: &dyn Trait = match opt() {
| _________________________^
LL | | Some(()) => &S,
LL | | None => &R,
LL | | };
| |_____^ `Trait` 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/wf-unsafe-trait-obj-match.rs:6:14
|
LL | trait Trait: Sized {}
| ----- ^^^^^ ...because it requires `Self: Sized`
| |
| this trait cannot be made into an object...
= help: the following types implement the trait, consider defining an enum where each variant holds one of these types, implementing `Trait` for this new enum and using it instead:
S
R
= note: required for the cast from `&R` to `&dyn Trait`
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0038, E0308.
For more information about an error, try `rustc --explain E0038`.
|
