pub(crate) fn extend_span(&mut self) -> Result<(), Error> {
        match self {
            Node::Terminal(_) => Err(format_err!("Can't extend terminal's span.")),
            Node::NonTerminal(nt) => {
                nt.span.extend();
                Ok(())
            }
        }
    }
/// Extend the upper bounds of a span.
Extend the upper bounds of a span.
Extend the upper bounds of a span .
pub(crate) fn extend_span(&mut self) -> Result<(), Error> {
        match self {
            Node::Terminal(_) => Err(format_err!("Can't extend terminal's span.")),
            Node::NonTerminal(nt) => {
                nt.span.extend();
                Ok(())
            }
        }
    }
pub ( crate ) fn extend_span ( & mut self ) -> Result < ( ) , Error > { match self { Node :: Terminal ( _ ) => Err ( format_err ! ( " " ) ) , Node :: NonTerminal ( nt ) => { nt . span . extend ( ) ; Ok ( ( ) ) } } }
Extend the upper bounds of a span.
Extend the upper bounds of a span .
&mut self
&mut self