Incorrect "Leftover tokens" error with `$(…)?` repetition

rust-analyzer version: 0.3.2845-standalone

rustc version: current stable, but shouldn't matter

editor or extension: VS Code

relevant settings: n/a

code snippet to reproduce:

#[macro_export]
macro_rules! attr {
    ($t:ty) => {
        {
            $crate::attr_array!($t; 1);
        }
    };
}

#[macro_export]
macro_rules! attr_array {
    ($( $t:ty; )? $count:expr) => {
        [(); $count]  // expected (), found [(); _]
    };
}

fn make<T>() {
    attr!(T)  // leftover tokens
}

rust-analyzer reports 2 incorrect errors, but rustc accepts this code fine.

Unlike the other issues that mention this particular error, my reproduction seems to depend on a $(…)? or $(…)* repetition being present (a + repetition makes the error go away), so I figured I'd file a separate issue.

Reproduce the supplied macro snippet in rust-analyzer and compare its diagnostics with rustc, focusing on the optional $(...)? repetition in attr_array!. Done when rust-analyzer stops reporting the two errors that rustc does not report and still handles the shown macro expansion correctly.