syntax_data: {"ast_node_type":"other","tokens":[{"end":48,"kind":"keyword","start":0,"text":"\"emit"}]}
source_snippet:         "emit bitcode in rlibs (default: yes)"),
context_before:     embed_bitcode: bool = (true, parse_bool, [TRACKED],
context_after:     extra_filename: String = (String::new(), parse_string, [UNTRACKED],