syntax_data: {"ast_node_type":"other","tokens":[{"end":53,"kind":"keyword","start":0,"text":".collect::<BTreeMap<_,"}]}
source_snippet:                         .collect::<BTreeMap<_, _>>();
context_before:                         .map(|(k, v)| (k.desc().to_string(), v.clone()))
context_after:                     d.insert(name.to_string(), obj.to_json());