fn push_rhs_delimiter<'s>(
entered: &Stack<EnteredDelimiter<'s>>,
delimiter: &'s Syntax<'s>
) -> Stack<EnteredDelimiter<'s>>
fn push_rhs_delimiter<'s>(
entered: &Stack<EnteredDelimiter<'s>>,
delimiter: &'s Syntax<'s>
) -> Stack<EnteredDelimiter<'s>>