{"ast_node_type":"function","tokens":[{"end":86,"kind":"keyword","start":0,"text":"fn"}]}
    fn new(body: &'mir Body<'tcx>, tcx: TyCtxt<'tcx>) -> ConstPropagator<'mir, 'tcx> {
impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
        let def_id = body.source.def_id();