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error[E0277]: `?` couldn't convert the error to `String`
--> $DIR/question-mark-result-err-mismatch.rs:14:22
|
LL | fn foo() -> Result<String, String> {
| ---------------------- expected `String` because of this
...
LL | .map_err(|e| {
| __________-
LL | | e;
| | - help: remove this semicolon
LL | | })
| |__________- this can't be annotated with `?` because it has type `Result<_, ()>`
LL | .map(|()| "")?;
| ^ the trait `From<()>` is not implemented for `String`
|
= note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
= note: required for `Result<String, String>` to implement `FromResidual<Result<Infallible, ()>>`
error[E0277]: `?` couldn't convert the error to `String`
--> $DIR/question-mark-result-err-mismatch.rs:28:25
|
LL | fn bar() -> Result<(), String> {
| ------------------ expected `String` because of this
LL | let x = foo();
| ----- this has type `Result<_, String>`
...
LL | .map_err(|_| ())?;
| ---------------^ the trait `From<()>` is not implemented for `String`
| |
| this can't be annotated with `?` because it has type `Result<_, ()>`
|
= 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>`:
<String as From<char>>
<String as From<Box<str>>>
<String as From<Cow<'a, str>>>
<String as From<&str>>
<String as From<&mut str>>
<String as From<&String>>
= note: required for `Result<(), String>` to implement `FromResidual<Result<Infallible, ()>>`
error[E0277]: `?` couldn't convert the error to `String`
--> $DIR/question-mark-result-err-mismatch.rs:48:11
|
LL | fn baz() -> Result<String, String> {
| ---------------------- expected `String` because of this
...
LL | .ok_or_else(|| {
| __________-
LL | | "Couldn't split the test string";
| | - help: remove this semicolon
LL | | })?;
| | -^ the trait `From<()>` is not implemented for `String`
| |__________|
| this can't be annotated with `?` because it has type `Result<_, ()>`
|
= note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
= note: required for `Result<String, String>` to implement `FromResidual<Result<Infallible, ()>>`
error: aborting due to 3 previous errors
For more information about this error, try `rustc --explain E0277`.
|
