1 error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a function that returns `Result`
2 --> $DIR/try-on-option.rs:5:6
4 LL | fn foo() -> Result<u32, ()> {
5 | --------------------------- this function returns a `Result`
6 LL | let x: Option<u32> = None;
8 | ^ use `.ok_or(...)?` to provide an error compatible with `Result<u32, ()>`
10 = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `Result<u32, ()>`
11 = help: the following other types implement trait `FromResidual<R>`:
12 <Result<T, F> as FromResidual<Result<Infallible, E>>>
13 <Result<T, F> as FromResidual<Yeet<E>>>
15 error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
16 --> $DIR/try-on-option.rs:11:6
18 LL | fn bar() -> u32 {
19 | --------------- this function should return `Result` or `Option` to accept `?`
20 LL | let x: Option<u32> = None;
22 | ^ cannot use the `?` operator in a function that returns `u32`
24 = help: the trait `FromResidual<Option<Infallible>>` is not implemented for `u32`
26 error: aborting due to 2 previous errors
28 For more information about this error, try `rustc --explain E0277`.