{"ast_node_type":"variable","tokens":[{"end":81,"kind":"keyword","start":0,"text":"let"}]}
        let is_empty = cx.ctors_for_ty(&ty).is_ok_and(|ctors| ctors.all_empty());
    pub(crate) fn wildcard(cx: &Cx, ty: Cx::Ty) -> Self {
        let ctor = if is_empty { Never } else { Wildcard };