/// Reasons a program might have rejected an instruction.
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum ProgramError {
    /// Contract's transactions resulted in an account with a negative balance
    /// The difference from InsufficientFundsForFee is that the transaction was executed by the
    /// contract
    ResultWithNegativeTokens,

    /// The program returned an error
    RuntimeError,

    /// Program's instruction token balance does not equal the balance after the instruction
    UnbalancedInstruction,

    /// Program modified an account's program id
    ModifiedProgramId,

    /// Program spent the tokens of an account that doesn't belong to it
    ExternalAccountTokenSpend,
}