| struct E; |
| //~^ NOTE `E` needs to implement `std::error::Error` |
| //~| NOTE alternatively, `E` needs to implement `Into<X>` |
| struct X; //~ NOTE `X` needs to implement `From<E>` |
| |
| fn foo() -> Result<(), Box<dyn std::error::Error>> { //~ NOTE required `E: std::error::Error` because of this |
| Ok(bar()?) |
| //~^ ERROR `?` couldn't convert the error: `E: std::error::Error` is not satisfied |
| //~| NOTE the trait `std::error::Error` is not implemented for `E` |
| //~| NOTE the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait |
| //~| NOTE required for `Box<dyn std::error::Error>` to implement `From<E>` |
| //~| NOTE this has type `Result<_, E>` |
| //~| NOTE in this expansion |
| //~| NOTE in this expansion |
| //~| NOTE in this expansion |
| } |
| fn bat() -> Result<(), X> { //~ NOTE expected `X` because of this |
| Ok(bar()?) |
| //~^ ERROR `?` couldn't convert the error to `X` |
| //~| NOTE the trait `From<E>` is not implemented for `X` |
| //~| NOTE this can't be annotated with `?` because it has type `Result<_, E>` |
| //~| NOTE the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait |
| //~| NOTE in this expansion |
| //~| NOTE in this expansion |
| } |
| fn bar() -> Result<(), E> { |
| Err(E) |
| } |
| fn main() {} |
