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error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
--> $DIR/try-operator-on-main.rs:7:31
|
LL | fn main() {
| --------- this function should return `Result` or `Option` to accept `?`
LL | // error for a `Try` type on a non-`Try` fn
LL | std::fs::File::open("foo")?;
| ^ cannot use the `?` operator in a function that returns `()`
|
= help: the trait `FromResidual<Result<Infallible, std::io::Error>>` is not implemented for `()`
error[E0277]: the `?` operator can only be applied to values that implement `Try`
--> $DIR/try-operator-on-main.rs:10:5
|
LL | ()?;
| ^^^ the `?` operator cannot be applied to type `()`
|
= help: the trait `Try` is not implemented for `()`
error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
--> $DIR/try-operator-on-main.rs:10:7
|
LL | fn main() {
| --------- this function should return `Result` or `Option` to accept `?`
...
LL | ()?;
| ^ cannot use the `?` operator in a function that returns `()`
|
= help: the trait `FromResidual<_>` is not implemented for `()`
error[E0277]: the trait bound `(): Try` is not satisfied
--> $DIR/try-operator-on-main.rs:14:25
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LL | try_trait_generic::<()>();
| ^^ the trait `Try` is not implemented for `()`
|
note: required by a bound in `try_trait_generic`
--> $DIR/try-operator-on-main.rs:17:25
|
LL | fn try_trait_generic<T: Try>() -> T {
| ^^^ required by this bound in `try_trait_generic`
error[E0277]: the `?` operator can only be applied to values that implement `Try`
--> $DIR/try-operator-on-main.rs:19:5
|
LL | ()?;
| ^^^ the `?` operator cannot be applied to type `()`
|
= help: the trait `Try` is not implemented for `()`
error: aborting due to 5 previous errors
For more information about this error, try `rustc --explain E0277`.
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