{"ast_node_type":"other","tokens":[{"end":83,"kind":"keyword","start":0,"text":"self.at(&ObligationCause::dummy_with_span(span),"}]}
                        self.at(&ObligationCause::dummy_with_span(span), param_env)
                    goals.extend(
                            .eq(DefineOpaqueTypes::Yes, prev, hidden_ty)?