syntax_data: {"ast_node_type":"function","tokens":[{"end":60,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet:     pub fn ungate_last(&self, feature: Symbol, span: Span) {
context_before:     /// Using this is discouraged unless you have a really good reason to.
context_after:         let removed_span = self.spans.borrow_mut().entry(feature).or_default().pop().unwrap();