syntax_data: {"ast_node_type":"other","tokens":[{"end":35,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:             if visited.insert(ty) {
context_before:         ty::Tuple(tys) => tys.iter().find_map(|ty| {
context_after:                 return characteristic_def_id_of_type_cached(ty, visited);