{"ast_node_type":"other","tokens":[{"end":72,"kind":"keyword","start":0,"text":"IndexVec::from_elem_n(None,"}]}
                        IndexVec::from_elem_n(None, provided_arg_count);
                    let mut real_idxs: IndexVec<ProvidedIdx, Option<(ExpectedIdx, ProvidedIdx)>> =
                    for (src, dst) in