{"ast_node_type":"other","tokens":[{"end":83,"kind":"keyword","start":0,"text":"///"}]}
    /// Returns `None` if there are multiple non-1-ZST fields or only 1-ZST-fields.
    /// Finds the one field that is not a 1-ZST.
    pub fn non_1zst_field<C>(&self, cx: &C) -> Option<(FieldIdx, Self)>