let ... = ... else {} badly and infinitely indented with repeated formatting

[madonuko]

This issue is similar to #4609.

To reproduce:

macro_rules! a {
    () => {
        let x = y else {
            any
        };
    };
}

fn b() {
    let Some(x) = Some("hai") else {panic!("oops");};
}

d!(
    macro x() {
        let x = y else {
            any
        };
    }
);

Run $ rustfmt test.rs

And now you get this:

macro_rules! a {
    () => {
        let x = y else {
                    any
                };
    };
}

fn b() {
    let Some(x) = Some("hai") else {panic!("oops");};
}

d!(
    macro x() {
        let x = y else {
                    any
                };
    }
);

Notice the bad indentation in macro_rules! a and d!(...) and the unchanged bad indentation in b().

for d!(), this only happens with:

• macro invocation with !()
• the macro keyword (weird!)
• and it should look like a function except you replace fn with macro
• and of course the let ... = ... else {}; statement; yes you need ;

And for the case in b() it just happens anywhere; seems like there is no support for formatting let ... = ... else {}; statements in rustfmt?

Some of the affected versions

• rustfmt 1.5.1-stable (d5a82bb 2023-02-07)
• rustfmt 1.5.2-stable (8ede3aa 2023-07-12)

[calebcartwright]

Thanks but I'm going to close because this is a duplicate of #5503 and you need to have rustfmt v1.6.0 or higher to have a version that has formatting support for let-else statements. That version of rustfmt should be on stable in Rust 1.72, and has been out on the nightly toolchains for a while.

Some docs/links below for reference:
https://github.com/rust-lang/rustfmt/blob/master/CHANGELOG.md#160-2023-07-02
#4914
https://blog.rust-lang.org/2023/07/01/rustfmt-supports-let-else-statements.html