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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-on-option-diagnostics.rs:7:6
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LL | / fn a_function() -> u32 {
LL | | let x: Option<u32> = None;
LL | | x?;
| | ^ cannot use the `?` operator in a function that returns `u32`
LL | | 22
LL | | }
| |_- this function should return `Result` or `Option` to accept `?`
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= help: the trait `FromResidual<Option<Infallible>>` is not implemented for `u32`
error[E0277]: the `?` operator can only be used in a closure that returns `Result` or `Option` (or another type that implements `FromResidual`)
--> $DIR/try-on-option-diagnostics.rs:14:10
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LL | let a_closure = || {
| _____________________-
LL | | let x: Option<u32> = None;
LL | | x?;
| | ^ cannot use the `?` operator in a closure that returns `{integer}`
LL | | 22
LL | | };
| |_____- this function should return `Result` or `Option` to accept `?`
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= help: the trait `FromResidual<Option<Infallible>>` is not implemented for `{integer}`
error[E0277]: the `?` operator can only be used in a method that returns `Result` or `Option` (or another type that implements `FromResidual`)
--> $DIR/try-on-option-diagnostics.rs:26:14
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LL | / fn a_method() {
LL | | let x: Option<u32> = None;
LL | | x?;
| | ^ cannot use the `?` operator in a method that returns `()`
LL | | }
| |_________- this function should return `Result` or `Option` to accept `?`
|
= help: the trait `FromResidual<Option<Infallible>>` is not implemented for `()`
error[E0277]: the `?` operator can only be used in a trait method that returns `Result` or `Option` (or another type that implements `FromResidual`)
--> $DIR/try-on-option-diagnostics.rs:39:14
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LL | / fn a_trait_method() {
LL | | let x: Option<u32> = None;
LL | | x?;
| | ^ cannot use the `?` operator in a trait method that returns `()`
LL | | }
| |_________- this function should return `Result` or `Option` to accept `?`
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= help: the trait `FromResidual<Option<Infallible>>` is not implemented for `()`
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0277`.
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