{"ast_node_type":"other","tokens":[{"end":53,"kind":"keyword","start":0,"text":"$(${ignore($mut)}"}]}
            $(${ignore($mut)} vis.visit_span(span))?;
        fn visit_span<$($lt,)? V: $Visitor$(<$lt>)?>(vis: &mut V, span: &$($lt)? $($mut)? Span) -> V::Result {
            V::Result::output()