syntax_data: {"ast_node_type":"other","tokens":[{"end":74,"kind":"keyword","start":0,"text":"feature_warn_issue(sess,"}]}
source_snippet:     feature_warn_issue(sess, feature, span, GateIssue::Language, explain);
context_before: pub fn feature_warn(sess: &Session, feature: Symbol, span: Span, explain: &'static str) {
context_after: }