syntax_data: {"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"///"}]}
source_snippet: /// The `feature`'s `Symbol` is the one you used in `unstable.rs` and `rustc_span::symbol`.
context_before: /// Construct a diagnostic for a language feature error due to the given `span`.
context_after: #[track_caller]