{"ast_node_type":"other","tokens":[{"end":29,"kind":"keyword","start":0,"text":"match"}]}
                match *self {
            pub fn header(&'a $($mut)? self) -> Option<&'a $($mut)? FnHeader> {
                    FnKind::Fn(_, _, Fn { sig, .. }) => Some(&$($mut)? sig.header),