? operator for propagating Reslut, Option - does clippy give false positive warning ?

[tomaszdrozdz]

Description

Hello all,

Is this warning OK - or false positive ?

let r: Result<i32, std::num::ParseIntError> = (|| -> Result<i32, std::num::ParseIntError> { 
    Ok("1".parse::<i32>()?) })();

Gives:

question mark operator is useless here
for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_question_mark
#[warn(clippy::needless_question_mark)] on by default

---

But of course:

let r: Result<i32, std::num::ParseIntError> = (|| -> Result<i32, std::num::ParseIntError> { 
    Ok("1".parse::<i32>() ) })();

Gives:

mismatched types
expected type i32
found enum std::result::Result<i32, std::num::ParseIntError>

---

And this:

let r: Result<i32, std::num::ParseIntError> = (|| -> Result<i32, std::num::ParseIntError> { 
    Ok("1".parse::<i32>()? + "2".parse::<i32>()?) })();

does not produce warning.

Version

Additional Labels

No response

[Alexendoo]

Tweaked the message to be clearer in #14682, the lint wants you to remove the Ok as well as the ?

[tomaszdrozdz]

Thank You :)