{"ast_node_type":"function","tokens":[{"end":53,"kind":"keyword","start":0,"text":"fn"}]}
    fn known_to_be_zst(&self, ty: Ty<'tcx>) -> bool {
impl<'tcx> Replacer<'_, 'tcx> {
        if let Some(is_zst) = trivially_zst(ty, self.tcx) {