Esteban Küber 6c3879d1f1 Provide context when ? can't be called because of Result<_, E> ... When a method chain ending in `?` causes an E0277 because the expression's `Result::Err` variant doesn't have a type that can be converted to the `Result<_, E>` type parameter in the return type, provide additional context of which parts of the chain can and can't support the `?` operator. ``` 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 can be annotated with `?` because it has type `Result<String, String>` LL | let one = x LL | .map(|s| ()) | ----------- this can be annotated with `?` because it 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, ()>>` ``` Fix #72124.		2023-12-05 22:22:08 +00:00
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bad-interconversion.rs
bad-interconversion.stderr	Provide context when ? can't be called because of Result<_, E>	2023-12-05 22:22:08 +00:00
issue-32709.rs	Move tests	2023-08-28 17:47:37 -03:00
issue-32709.stderr	Provide context when ? can't be called because of Result<_, E>	2023-12-05 22:22:08 +00:00
option-to-result.rs
option-to-result.stderr	Don't sort strings right after we just sorted by types	2023-06-27 23:31:06 +00:00
try-as-monad.rs
try-on-option-diagnostics.rs
try-on-option-diagnostics.stderr
try-on-option.rs
try-on-option.stderr	Don't sort strings right after we just sorted by types	2023-06-27 23:31:06 +00:00
try-operator-custom.rs
try-operator-on-main.rs
try-operator-on-main.stderr
try-poll.rs
yeet-for-option.rs
yeet-for-result.rs