BondLadder

    )]    pub config: Account<'info, OracleConfig>,     #[account(mut)]    pub authority: Signer<'info>,     pub system_program: Program<'info, System>,} #[derive(Accounts)]pub struct PublishRating<'info> {    #[account(        seeds = [OracleConfig::SEED],        bump = config.bump,        has_one = authority,    )]    pub config: Account<'info, OracleConfig>,     // init_if_needed тут безпечний: запис перезаписується цілком, а доступ уже    // звужений has_one на конфізі — повторна ініціалізація не дає authority    // нічого понад те, що він і так може зробити наступною публікацією.    #[account(        init_if_needed,        payer = authority,

1. Line 65 pub authority: Signer<'info>,: Requires this account to have signed the transaction.
2. Line 73 seeds = [OracleConfig::SEED],: Declares the PDA seeds. Anchor re-derives the address and rejects the account if it doesn't match.
3. Line 74 bump = config.bump,: Uses the bump seed, the extra byte that pushes the derived address off the ed25519 curve.
4. Line 75 has_one = authority,: Checks that a stored pubkey field matches the passed account.
5. Line 79 // init_if_needed тут безпечний: запис перезаписується цілком, а доступ уже: Creates the account only if it doesn't exist. Watch for re-initialisation bugs.

    #[account(        init,        payer = authority,        space = 8 + IssuerConfig::INIT_SPACE,        seeds = [IssuerConfig::SEED],        bump,    )]    pub config: Account<'info, IssuerConfig>,     pub usdc_mint: Account<'info, Mint>,     #[account(mut)]    pub authority: Signer<'info>,     pub system_program: Program<'info, System>,} #[derive(Accounts)]pub struct RegisterInstrument<'info> {    #[account(        seeds = [IssuerConfig::SEED],        bump = config.bump,        has_one = authority,    )]

1. Line 74 init,: Creates and pays for a new account. Space and payer must be specified.
2. Line 77 seeds = [IssuerConfig::SEED],: Declares the PDA seeds. Anchor re-derives the address and rejects the account if it doesn't match.
3. Line 78 bump,: Uses the bump seed, the extra byte that pushes the derived address off the ed25519 curve.
4. Line 85 pub authority: Signer<'info>,: Requires this account to have signed the transaction.
5. Line 95 has_one = authority,: Checks that a stored pubkey field matches the passed account.

pub fn handler(ctx: Context<MintForUsdc>, amount_micro: u64) -> Result<Fill> {    let price_micro = ctx.accounts.instrument.price_micro;    require!(price_micro > 0, IssuerError::InvalidPrice);    require!(        Clock::get()?.unix_timestamp < ctx.accounts.instrument.maturity_ts,        IssuerError::MaturityInThePast    );     let Fill { units, spent_micro } = fill_for_share(amount_micro, price_micro);    require!(units > 0, IssuerError::AmountBelowUnitPrice);     token::transfer(        CpiContext::new(            ctx.accounts.token_program.to_account_info(),            Transfer {                from: ctx.accounts.buyer_usdc.to_account_info(),                to: ctx.accounts.treasury.to_account_info(),                authority: ctx.accounts.buyer.to_account_info(),            },        ),        spent_micro,    )?;     token::mint_to(

1. Line 27 require!(price_micro > 0, IssuerError::InvalidPrice);: An explicit validation that aborts the instruction with an error.
2. Line 29 Clock::get()?.unix_timestamp < ctx.accounts.instrument.maturity_ts,: Reads on-chain time from the Clock sysvar.
3. Line 36 token::transfer(: An SPL token transfer through the Token Program.
4. Line 37 CpiContext::new(: Makes a cross-program invocation into another program.
5. Line 48 token::mint_to(: Mints new tokens. The mint authority must sign.

        .checked_sub(settled.principal_micro)        .ok_or_else(|| error!(LadderError::MathOverflow))?;    position.fee_accrued = settled.fee_carried_micro;    position.last_fee_ts = now_ts;     Ok(())} /// Holdings arrive in `remaining_accounts`, so the address is checked here/// rather than by a seeds constraint, and the first exit through an/// instrument creates its holding.fn credit_holding<'info>(    holding: &AccountInfo<'info>,    rung: &Rung,    units: u64,    payer: &Signer<'info>,    system_program: &Program<'info, System>,) -> Result<()> {    let (address, bump) = Pubkey::find_program_address(        &[BackstopHolding::SEED, rung.instrument.as_ref()],        &crate::ID,    );    require_keys_eq!(holding.key(), address, ErrorCode::ConstraintSeeds);

1. Line 181 .checked_sub(settled.principal_micro): Uses checked arithmetic so overflow fails instead of wrapping.
2. Line 196 payer: &Signer<'info>,: Requires this account to have signed the transaction.
3. Line 199 let (address, bump) = Pubkey::find_program_address(: Derives a PDA from seeds and the program ID and returns the address with its canonical bump.
4. Line 199 let (address, bump) = Pubkey::find_program_address(: Uses the bump seed, the extra byte that pushes the derived address off the ed25519 curve.
5. Line 203 require_keys_eq!(holding.key(), address, ErrorCode::ConstraintSeeds);: An explicit validation that aborts the instruction with an error.