syntax_data: {"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"sm.new_source_file(PathBuf::from(\"blork.rs\").into(),"}]}
source_snippet:     sm.new_source_file(PathBuf::from("blork.rs").into(), "first line.\nsecond line".to_string());
context_before:     let sm = SourceMap::new(FilePathMapping::empty());
context_after:     sm.new_source_file(PathBuf::from("empty.rs").into(), String::new());