syntax_data: {"ast_node_type":"variable","tokens":[{"end":81,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let variant = if def.is_struct() { None } else { Some(v_index) };
context_before:             for (v_index, v_def) in def.variants().iter_enumerated() {
context_after:                 for (f_index, f_def) in v_def.fields.iter().enumerate() {