{"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"self.dcx().emit_err(errors::ConstraintOnNegativeBound"}]}
                                    self.dcx().emit_err(errors::ConstraintOnNegativeBound {
                                if let ast::AngleBracketedArg::Constraint(constraint) = arg {
                                        span: constraint.span,