Rustfmt: Combine all delimited exprs as last argument

Summary

  • Some expressions with multi-line final arguments will now format as a single line, with the final expression overflowing.

Details

When structs, slices, arrays, and block/array-like macros are used as the last argument in an expression list, they are now allowed to overflow (like blocks/closures) instead of being indented on a new line.

// Edition 2021

fn example() {
    foo(ctx, |param| {
        action();
        foo(param)
    });

    foo(
        ctx,
        Bar {
            x: value,
            y: value2,
        },
    );

    foo(
        ctx,
        &[
            MAROON_TOMATOES,
            PURPLE_POTATOES,
            ORGANE_ORANGES,
            GREEN_PEARS,
            RED_APPLES,
        ],
    );

    foo(
        ctx,
        vec![
            MAROON_TOMATOES,
            PURPLE_POTATOES,
            ORGANE_ORANGES,
            GREEN_PEARS,
            RED_APPLES,
        ],
    );
}

This now formats as the following in the 2024 style edition:

// Edition 2024

fn example() {
    foo(ctx, |param| {
        action();
        foo(param)
    });

    foo(ctx, Bar {
        x: value,
        y: value2,
    });

    foo(ctx, &[
        MAROON_TOMATOES,
        PURPLE_POTATOES,
        ORGANE_ORANGES,
        GREEN_PEARS,
        RED_APPLES,
    ]);

    foo(ctx, vec![
        MAROON_TOMATOES,
        PURPLE_POTATOES,
        ORGANE_ORANGES,
        GREEN_PEARS,
        RED_APPLES,
    ]);
}

Migration

The change can be applied automatically by running cargo fmt or rustfmt with the 2024 Edition. See the Style edition chapter for more information on migrating and how style editions work.