syntax_data: {"ast_node_type":"function","tokens":[{"end":89,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet: pub fn feature_warn(sess: &Session, feature: Symbol, span: Span, explain: &'static str) {
context_before: #[track_caller]
context_after:     feature_warn_issue(sess, feature, span, GateIssue::Language, explain);