{"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"self.psess.gated_spans.gate(sym::const_trait_impl,"}]}
            self.psess.gated_spans.gate(sym::const_trait_impl, span);
            let span = start.to(self.prev_token.span);
            BoundConstness::Maybe(span)