main() {
    let x: u64;
    let imm_ref: &u64;

    x = 5;
    imm_ref = &x;
    imm_ref = freeze(move(imm_ref));
    release(move(imm_ref));
    return;
}

// check: VerificationError { kind: FunctionDefinition, idx: 0, err: FreezeRefTypeMismatchError(6) }