1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
fn foo() -> Result<String, String> { //~ NOTE expected `String` because of this
let test = String::from("one,two");
let x = test
.split_whitespace()
.next()
.ok_or_else(|| {
"Couldn't split the test string"
});
let one = x
.map(|s| ())
.map_err(|e| { //~ NOTE this can't be annotated with `?` because it has type `Result<_, ()>`
e; //~ HELP remove this semicolon
})
.map(|()| "")?; //~ ERROR `?` couldn't convert the error to `String`
//~^ NOTE in this expansion of desugaring of operator `?`
//~| NOTE in this expansion of desugaring of operator `?`
//~| NOTE in this expansion of desugaring of operator `?`
//~| NOTE 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, ()>>`
Ok(one.to_string())
}
fn bar() -> Result<(), String> { //~ NOTE expected `String` because of this
let x = foo(); //~ NOTE this has type `Result<_, String>`
let one = x
.map(|s| ())
.map_err(|_| ())?; //~ ERROR `?` couldn't convert the error to `String`
//~^ NOTE in this expansion of desugaring of operator `?`
//~| NOTE in this expansion of desugaring of operator `?`
//~| NOTE in this expansion of desugaring of operator `?`
//~| NOTE in this expansion of desugaring of operator `?`
//~| NOTE this can't be annotated with `?` because it has type `Result<_, ()>`
//~| NOTE 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>` to implement `FromResidual<Result<Infallible, ()>>`
//~| HELP the following other types implement trait `From<T>`:
Ok(one)
}
fn baz() -> Result<String, String> { //~ NOTE expected `String` because of this
let test = String::from("one,two");
let one = test
.split_whitespace()
.next()
.ok_or_else(|| { //~ NOTE this can't be annotated with `?` because it has type `Result<_, ()>`
"Couldn't split the test string"; //~ HELP remove this semicolon
})?;
//~^ ERROR `?` couldn't convert the error to `String`
//~| NOTE in this expansion of desugaring of operator `?`
//~| NOTE in this expansion of desugaring of operator `?`
//~| NOTE in this expansion of desugaring of operator `?`
//~| NOTE 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, ()>>`
Ok(one.to_string())
}
fn main() {}
|
