Indentation in closures gets formatted twice and result is not nice™

[cdbrkfxrpt]

Describe the bug

On first invocation of rustfmt closure code gets formatted (nicely, arguably). On any subsequent iteration it gets formatted again (not so nicely, arguably).

To Reproduce

Throw the following in a test.rs file:

#[derive(Debug)]
struct Foo {
  some:   usize,
  member: String,
}

impl Foo {
  pub fn some_fn() {
    let edb_file = fs::read_dir(&event_path)?.find_map(|p| {
      let path = p.ok()?.path();
      (path.is_file() && Self::as_regex().is_match(&get_file_name(&path).ok()?) && path.extension()? == "edb").as_some(path)
    });
  }
}

and put the following in a rustfmt.toml file in the same directory:

# "Block" | "Visual"
indent_style = "Visual"

Now invoke rustfmt on file test.rs once. The following should happen:

#[derive(Debug)]
struct Foo {
    some: usize,
    member: String,
}

impl Foo {
    pub fn some_fn() {
        let edb_file = fs::read_dir(&event_path)?.find_map(|p| {
                           let path = p.ok()?.path();
                           (path.is_file()
                            && Self::as_regex().is_match(&get_file_name(&path).ok()?)
                            && path.extension()? == "edb")
                                                          .as_some(path)
                       });
    }
}

Now invoke rustfmt on file test.rs again, and the following should happen:

#[derive(Debug)]
struct Foo {
    some: usize,
    member: String,
}

impl Foo {
    pub fn some_fn() {
        let edb_file = fs::read_dir(&event_path)?.find_map(|p| {
                                                     let path = p.ok()?.path();
                                                     (path.is_file()
                            && Self::as_regex().is_match(&get_file_name(&path).ok()?)
                            && path.extension()? == "edb")
                                                          .as_some(path)
                                                 });
    }
}

Subsequent invocations should not make a difference. Differing settings for max_width (we use 79 characters) produce similar output.

Expected behavior

rustfmt should certainly not take two invocations to format a section of code. Personally I think the output after the first invocation is the intended one.

Meta

• rustfmt version: rustfmt 1.4.30-nightly (acd9486 2020-12-20)
• From where did you install rustfmt?: rustup
• How do you run rustfmt: through vim but this is reproducible also on direct invocation

[ytmimi]

Confirming I can reproduce this with rustfmt 1.5.1-nightly (9c8ccc32 2022-07-26)

Linking the tracking issues for indent_style (#3346)