{"ast_node_type":"function","tokens":[{"end":62,"kind":"keyword","start":0,"text":"pub(super)"}]}
    pub(super) fn insert_imm(&mut self, f: FieldIdx, imm: V) {
    /// necessary for writing things like enum tags that aren't in any variant.
        let field_offset = self.layout.fields.offset(f.as_usize());