Rustfmt fails to format code

[ImplOfAnImpl]

Rustfmt fails to format the following code.
Nothing is printed to the console. However, if I deliberately add a trailing whitespace somewhere, then it starts emitting the "left behind trailing whitespace" error, like in #2896

struct Foo;

impl Foo {
    async fn foo(&mut self) {
        if true {
            async {


                if true {
                    if true {

                        if true {



                                log::info!("A relatively long string 111111111111111111111111111111111111111111");





                        }
                    }
                }

            }
            .await;
        }
    }
}

Commenting out either the log or the await line fixes the issue.

My config:

max_width = 100
hard_tabs = false
tab_spaces = 4
array_width = 80
chain_width = 80
single_line_if_else_max_width = 50
newline_style = "Unix"
edition = "2021"

match_arm_leading_pipes = "Preserve"

Version:

$ rustfmt --version
rustfmt 1.8.0-stable (90b35a6239 2024-11-26)

[ytmimi]

The .await makes this a chain. The deeply nested nature of this code is what makes it hard fro rustfmt to deal with. The line containing log::info!("A relatively long string 111111111111111111111111111111111111111111"); is 114 characters long, which exceeds the max width.

If you bump the max_width to some sufficiently high number (I tried 120), then the code reformats:

struct Foo;

impl Foo {
    async fn foo(&mut self) {
        if true {
            async {
                if true {
                    if true {
                        if true {
                            log::info!("A relatively long string 111111111111111111111111111111111111111111");
                        }
                    }
                }
            }
            .await;
        }
    }
}

Given that max_width is a hard constraint for rustfmt I'd recommend refactoring code so that it isn't as deeply nested if you can.