syntax_data: {"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"self.spans.borrow_mut().entry(feature).or_default().push(span);"}]}
source_snippet:         self.spans.borrow_mut().entry(feature).or_default().push(span);
context_before:     pub fn gate(&self, feature: Symbol, span: Span) {
context_after:     }