pub(crate) fn __reduce<'input>(
source_id: usize,
__action: i16,
__lookahead_start: Option<&u32>,
__states: &mut Vec<i16>,
__symbols: &mut Vec<(u32, __Symbol, u32)>,
_: PhantomData<&'input ()>
) -> Option<Result<Expr, ParseError<u32, Token, CalError>>>