{"ast_node_type":"other","tokens":[{"end":76,"kind":"keyword","start":0,"text":"impl<'tcx>"}]}
impl<'tcx> FromIterator<DropckConstraint<'tcx>> for DropckConstraint<'tcx> {
    fn from_iter<I: IntoIterator<Item = DropckConstraint<'tcx>>>(iter: I) -> Self {