syntax_data: {"ast_node_type":"other","tokens":[{"end":78,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// so this boolean value is mostly used for enabling unstable _values_ of
context_before:     /// usual parsing of `-Z` options (see [`crate::config::nightly_options`]),
context_after:     /// stable options. That separate check doesn't handle boolean values, so