"Fill match arms" code action creates non-exhaustive match

I have code like this:

        let mut chars = s.chars().peekable();
        match chars.peek() {
            Some(&'+') => {
                chars.next();
            }
            Some(&'-') => {
                bigint.negative = true;
                chars.next();
            }
            _ => (),
        }

Rust analyzer (run through Emacs) suggests the "fill match arms" action which, when applied, changes the fallback match arm to:

        None => {}

However, that's incorrect because as the compiler points out, the patterns Some(&'\u{0}'..='*'), Some(&','), Some(&'.'..='\u{d7ff}') and 1 more not covered.