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|
error[E0277]: `?` couldn't convert the error to `u8`
--> $DIR/bad-interconversion.rs:6:20
|
LL | fn result_to_result() -> Result<u64, u8> {
| --------------- expected `u8` because of this
LL | Ok(Err(123_i32)?)
| ------------^ the trait `From<i32>` is not implemented for `u8`
| |
| this can't be annotated with `?` because it has type `Result<_, i32>`
|
= note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
= help: the following other types implement trait `From<T>`:
<u8 as From<bool>>
<u8 as From<NonZeroU8>>
= note: required for `Result<u64, u8>` to implement `FromResidual<Result<Infallible, i32>>`
error[E0277]: the `?` operator can only be used on `Result`s, not `Option`s, in a function that returns `Result`
--> $DIR/bad-interconversion.rs:11:12
|
LL | fn option_to_result() -> Result<u64, String> {
| -------------------------------------------- this function returns a `Result`
LL | Some(3)?;
| ^ use `.ok_or(...)?` to provide an error compatible with `Result<u64, String>`
|
= help: the trait `FromResidual<Option<Infallible>>` is not implemented for `Result<u64, String>`
= help: the following other types implement trait `FromResidual<R>`:
<Result<T, F> as FromResidual<Yeet<E>>>
<Result<T, F> as FromResidual<Result<Infallible, E>>>
error[E0277]: the `?` operator can only be used on `Result`s in a function that returns `Result`
--> $DIR/bad-interconversion.rs:17:31
|
LL | fn control_flow_to_result() -> Result<u64, String> {
| -------------------------------------------------- this function returns a `Result`
LL | Ok(ControlFlow::Break(123)?)
| ^ this `?` produces `ControlFlow<{integer}, Infallible>`, which is incompatible with `Result<u64, String>`
|
= help: the trait `FromResidual<ControlFlow<{integer}, Infallible>>` is not implemented for `Result<u64, String>`
= help: the following other types implement trait `FromResidual<R>`:
<Result<T, F> as FromResidual<Yeet<E>>>
<Result<T, F> as FromResidual<Result<Infallible, E>>>
error[E0277]: the `?` operator can only be used on `Option`s, not `Result`s, in a function that returns `Option`
--> $DIR/bad-interconversion.rs:22:22
|
LL | fn result_to_option() -> Option<u16> {
| ------------------------------------ this function returns an `Option`
LL | Some(Err("hello")?)
| ^ use `.ok()?` if you want to discard the `Result<Infallible, &str>` error information
|
= help: the trait `FromResidual<Result<Infallible, &str>>` is not implemented for `Option<u16>`
= help: the following other types implement trait `FromResidual<R>`:
<Option<T> as FromResidual<Yeet<()>>>
<Option<T> as FromResidual>
error[E0277]: the `?` operator can only be used on `Option`s in a function that returns `Option`
--> $DIR/bad-interconversion.rs:27:33
|
LL | fn control_flow_to_option() -> Option<u64> {
| ------------------------------------------ this function returns an `Option`
LL | Some(ControlFlow::Break(123)?)
| ^ this `?` produces `ControlFlow<{integer}, Infallible>`, which is incompatible with `Option<u64>`
|
= help: the trait `FromResidual<ControlFlow<{integer}, Infallible>>` is not implemented for `Option<u64>`
= help: the following other types implement trait `FromResidual<R>`:
<Option<T> as FromResidual<Yeet<()>>>
<Option<T> as FromResidual>
error[E0277]: the `?` operator can only be used on `ControlFlow`s in a function that returns `ControlFlow`
--> $DIR/bad-interconversion.rs:32:39
|
LL | fn result_to_control_flow() -> ControlFlow<String> {
| -------------------------------------------------- this function returns a `ControlFlow`
LL | ControlFlow::Continue(Err("hello")?)
| ^ this `?` produces `Result<Infallible, &str>`, which is incompatible with `ControlFlow<String>`
|
= help: the trait `FromResidual<Result<Infallible, &str>>` is not implemented for `ControlFlow<String>`
= help: the trait `FromResidual<ControlFlow<String, Infallible>>` is implemented for `ControlFlow<String>`
= help: for that trait implementation, expected `ControlFlow<String, Infallible>`, found `Result<Infallible, &str>`
error[E0277]: the `?` operator can only be used on `ControlFlow`s in a function that returns `ControlFlow`
--> $DIR/bad-interconversion.rs:37:12
|
LL | fn option_to_control_flow() -> ControlFlow<u64> {
| ----------------------------------------------- this function returns a `ControlFlow`
LL | Some(3)?;
| ^ this `?` produces `Option<Infallible>`, which is incompatible with `ControlFlow<u64>`
|
= help: the trait `FromResidual<Option<Infallible>>` is not implemented for `ControlFlow<u64>`
= help: the trait `FromResidual<ControlFlow<u64, Infallible>>` is implemented for `ControlFlow<u64>`
= help: for that trait implementation, expected `ControlFlow<u64, Infallible>`, found `Option<Infallible>`
error[E0277]: the `?` operator in a function that returns `ControlFlow<B, _>` can only be used on other `ControlFlow<B, _>`s (with the same Break type)
--> $DIR/bad-interconversion.rs:43:29
|
LL | fn control_flow_to_control_flow() -> ControlFlow<i64> {
| ----------------------------------------------------- this function returns a `ControlFlow`
LL | ControlFlow::Break(4_u8)?;
| ^ this `?` produces `ControlFlow<u8, Infallible>`, which is incompatible with `ControlFlow<i64>`
|
= help: the trait `FromResidual<ControlFlow<u8, Infallible>>` is not implemented for `ControlFlow<i64>`
= note: unlike `Result`, there's no `From`-conversion performed for `ControlFlow`
= help: the trait `FromResidual<ControlFlow<i64, Infallible>>` is implemented for `ControlFlow<i64>`
= help: for that trait implementation, expected `i64`, found `u8`
error: aborting due to 8 previous errors
For more information about this error, try `rustc --explain E0277`.
|
