| error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `std::ops::Try`) |
| --> $DIR/try-operator-on-main.rs:9:5 |
| | |
| LL | / fn main() { |
| 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 `()` |
| LL | | |
| ... | |
| LL | | try_trait_generic::<()>(); |
| LL | | } |
| | |_- this function should return `Result` or `Option` to accept `?` |
| | |
| = help: the trait `std::ops::Try` is not implemented for `()` |
| = note: required by `std::ops::Try::from_error` |
| |
| error[E0277]: the `?` operator can only be applied to values that implement `std::ops::Try` |
| --> $DIR/try-operator-on-main.rs:12:5 |
| | |
| LL | ()?; |
| | ^^^ the `?` operator cannot be applied to type `()` |
| | |
| = help: the trait `std::ops::Try` is not implemented for `()` |
| = note: required by `std::ops::Try::into_result` |
| |
| error[E0277]: the trait bound `(): std::ops::Try` is not satisfied |
| --> $DIR/try-operator-on-main.rs:15:25 |
| | |
| LL | try_trait_generic::<()>(); |
| | ^^ the trait `std::ops::Try` is not implemented for `()` |
| ... |
| 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 `std::ops::Try` |
| --> $DIR/try-operator-on-main.rs:22:5 |
| | |
| LL | ()?; |
| | ^^^ the `?` operator cannot be applied to type `()` |
| | |
| = help: the trait `std::ops::Try` is not implemented for `()` |
| = note: required by `std::ops::Try::into_result` |
| |
| error: aborting due to 4 previous errors |
| |
| For more information about this error, try `rustc --explain E0277`. |