{"ast_node_type":"other","tokens":[{"end":41,"kind":"keyword","start":0,"text":"with_metavar_spans(|mspans|"}]}
            with_metavar_spans(|mspans| {
            let close = metavar_span.with_ctxt(dspan.close.ctxt());
                mspans.insert(open, metavar_span) && mspans.insert(close, metavar_span)