[rustc.git] / src / doc / book / listings / ch09-error-handling / no-listing-06-question-mark-in-main / output.txt

$ cargo run
   Compiling error-handling v0.1.0 (file:///projects/error-handling)
error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
 --> src/main.rs:4:36
  |
3 | / fn main() {
4 | |     let f = File::open("hello.txt")?;
  | |                                    ^ cannot use the `?` operator in a function that returns `()`
5 | | }
  | |_- this function should return `Result` or `Option` to accept `?`
  |
  = help: the trait `FromResidual<Result<Infallible, std::io::Error>>` is not implemented for `()`
  = note: required by `from_residual`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.
error: could not compile `error-handling`

To learn more, run the command again with --verbose.
Commit	Line	Data
74b04a01 XL	1	$ cargo run
74b04a01 XL	2	Compiling error-handling v0.1.0 (file:///projects/error-handling)
94222f64 XL	3	error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
94222f64 XL	4	--> src/main.rs:4:36
74b04a01 XL	5	\|
	6	3 \| / fn main() {
	7	4 \| \| let f = File::open("hello.txt")?;
94222f64	8	\| \| ^ cannot use the `?` operator in a function that returns `()`
74b04a01 XL	9	5 \| \| }
	10	\| \|_- this function should return `Result` or `Option` to accept `?`
	11	\|
94222f64 XL	12	= help: the trait `FromResidual<Result<Infallible, std::io::Error>>` is not implemented for `()`
94222f64 XL	13	= note: required by `from_residual`
74b04a01 XL	14
	15	error: aborting due to previous error
	16
	17	For more information about this error, try `rustc --explain E0277`.
fc512014	18	error: could not compile `error-handling`
74b04a01 XL	19
74b04a01 XL	20	To learn more, run the command again with --verbose.