syntax_data: {"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"\"adds"}]}
source_snippet:         "adds unstable command line options to rustc interface (default: no)"),
context_before:     unstable_options: bool = (false, parse_no_value, [UNTRACKED],
context_after:     use_ctors_section: Option<bool> = (None, parse_opt_bool, [TRACKED],