syntax_data: {"ast_node_type":"variable","tokens":[{"end":50,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let name: FileName = Decodable::decode(d);
context_before:     fn decode(d: &mut D) -> SourceFile {
context_after:         let src_hash: SourceFileHash = Decodable::decode(d);