Strange formatting of `macro_rules!` macro

With Rust 1.77.1 and rustfmt 1.7.0, as well as on current nightly 2024-03-30, the following macro definition (playground)

macro_rules! assert_eq_and_type {
    ($left:expr, $right:expr $(,)?) => {
        {
            fn check_statically_same_type<T>(_: &T, _: &T) {}
            check_statically_same_type(&$left, &$right);
        }
        assert_eq!($left, $right);
    };
}

formats to

macro_rules! assert_eq_and_type {
    ($left:expr, $right:expr $(,)?) => {{
        fn check_statically_same_type<T>(_: &T, _: &T) {}
        check_statically_same_type(&$left, &$right);
    }
    assert_eq!($left, $right);};
}

This certainly doesn't look right to me. I looked at other reported macro-related issues but couldn't find any very similar issues.

Start with the reported macro_rules! definition and compare rustfmt 1.7.0 and nightly 2024-03-30 against the playground reproduction. Trace how the macro body is formatted, then verify that the resulting output preserves the intended block structure without producing the reported compressed braces and semicolon placement.