syntax_data: {"ast_node_type":"other","tokens":[{"end":75,"kind":"keyword","start":0,"text":".map(|fields|"}]}
source_snippet:                 .map(|fields| *fields[FieldIdx::ZERO].ty(tcx, args).kind())
context_before:                 .filter(|fields| fields.len() == 1)
context_after:             else {