60 lines
2.9 KiB
Rust
60 lines
2.9 KiB
Rust
fn foo() -> Result<String, String> { //~ NOTE expected `String` because of this
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let test = String::from("one,two");
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let x = test
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.split_whitespace()
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.next()
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.ok_or_else(|| {
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"Couldn't split the test string"
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});
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let one = x
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.map(|s| ())
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.map_err(|e| { //~ NOTE this can't be annotated with `?` because it has type `Result<_, ()>`
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e; //~ HELP remove this semicolon
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})
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.map(|()| "")?; //~ ERROR `?` couldn't convert the error to `String`
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//~^ NOTE in this expansion of desugaring of operator `?`
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//~| NOTE in this expansion of desugaring of operator `?`
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//~| NOTE in this expansion of desugaring of operator `?`
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//~| NOTE the trait `From<()>` is not implemented for `String`
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//~| NOTE the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
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//~| NOTE required for `Result<String, String>` to implement `FromResidual<Result<Infallible, ()>>`
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Ok(one.to_string())
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}
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fn bar() -> Result<(), String> { //~ NOTE expected `String` because of this
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let x = foo(); //~ NOTE this has type `Result<_, String>`
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let one = x
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.map(|s| ())
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.map_err(|_| ())?; //~ ERROR `?` couldn't convert the error to `String`
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//~^ NOTE in this expansion of desugaring of operator `?`
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//~| NOTE in this expansion of desugaring of operator `?`
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//~| NOTE in this expansion of desugaring of operator `?`
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//~| NOTE in this expansion of desugaring of operator `?`
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//~| NOTE this can't be annotated with `?` because it has type `Result<_, ()>`
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//~| NOTE the trait `From<()>` is not implemented for `String`
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//~| NOTE the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
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//~| NOTE required for `Result<(), String>` to implement `FromResidual<Result<Infallible, ()>>`
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//~| HELP the following other types implement trait `From<T>`:
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Ok(one)
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}
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fn baz() -> Result<String, String> { //~ NOTE expected `String` because of this
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let test = String::from("one,two");
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let one = test
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.split_whitespace()
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.next()
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.ok_or_else(|| { //~ NOTE this can't be annotated with `?` because it has type `Result<_, ()>`
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"Couldn't split the test string"; //~ HELP remove this semicolon
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})?;
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//~^ ERROR `?` couldn't convert the error to `String`
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//~| NOTE in this expansion of desugaring of operator `?`
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//~| NOTE in this expansion of desugaring of operator `?`
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//~| NOTE in this expansion of desugaring of operator `?`
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//~| NOTE the trait `From<()>` is not implemented for `String`
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//~| NOTE the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
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//~| NOTE required for `Result<String, String>` to implement `FromResidual<Result<Infallible, ()>>`
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Ok(one.to_string())
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}
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fn main() {}
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