add-ix-arg.rs

// Old code
pub fn test_ix<'info>(
    _ctx: Context<'_, '_, '_, 'info, TestIx<'info>>,
) -> Result<()> {
    Ok(())
}

// New code
pub fn test_ix<'info>(
    _ctx: Context<'_, '_, '_, 'info, TestIx<'info>>,
    _test: Option<bool>,
) -> Result<()> {
    Ok(())
}

// Error
// Error: AnchorError occurred. Error Code: InstructionDidNotDeserialize. Error Number: 102. Error Message: The program could not deserialize the given instruction.