Understand the failure.
Verify the repair.
Small, reproducible software failures. The broken implementation, the fix that didn’t work, and the one that passed—preserved together.
Explore the cases ↓How results are verified ↗WHAT THE ARCHIVE CONTAINS
100840 executable cases. 20168 are open.
Every case records the implementation that fails, the fix that did not work, and the repair that passed its checks—with recorded outputs and source hashes. This release adds 100840 cases across 20168 failure mechanisms and 254 domains.
The open tier gives you the failure and the unsuccessful fix for one case in every mechanism. The remaining 80672 cases, 5 variants per mechanism, are member-only: the verified repair, its recorded checks, and the full fixture suite are held in the member archive. Read the methodology ↗
A RECORD OF WHAT WENT WRONG
Browse the archive / 100840
Credit line average daily balance: minimum payment cap · case 01
The minimum payment due exceeds the total owed on small balances.
Credit line average daily balance: minimum payment cap · case 02
The minimum payment due exceeds the total owed on small balances.
Credit line average daily balance: minimum payment cap · case 03
The minimum payment due exceeds the total owed on small balances.
Credit line average daily balance: minimum payment cap · case 04
The minimum payment due exceeds the total owed on small balances.
Credit line average daily balance: minimum payment cap · case 05
The minimum payment due exceeds the total owed on small balances.
Credit line average daily balance: minimum payment components · case 01
Minimum payments do not cover the cycle interest.
Credit line average daily balance: minimum payment components · case 02
Minimum payments do not cover the cycle interest.
Credit line average daily balance: minimum payment components · case 03
Minimum payments do not cover the cycle interest.
Credit line average daily balance: minimum payment components · case 04
Minimum payments do not cover the cycle interest.
Credit line average daily balance: minimum payment components · case 05
Minimum payments do not cover the cycle interest.
Credit line average daily balance: average daily balance divisor · case 01
Average daily balance is wrong in 28 and 31 day cycles.
Credit line average daily balance: average daily balance divisor · case 02
Average daily balance is wrong in 28 and 31 day cycles.
Credit line average daily balance: average daily balance divisor · case 03
Average daily balance is wrong in 28 and 31 day cycles.
Credit line average daily balance: average daily balance divisor · case 04
Average daily balance is wrong in 28 and 31 day cycles.
Credit line average daily balance: average daily balance divisor · case 05
Average daily balance is wrong in 28 and 31 day cycles.
Graduated payment schedule: step compounding base · case 01
Later-year payments grow linearly instead of compounding.
Graduated payment schedule: step compounding base · case 02
Later-year payments grow linearly instead of compounding.
Graduated payment schedule: step compounding base · case 03
Later-year payments grow linearly instead of compounding.
Graduated payment schedule: step compounding base · case 04
Later-year payments grow linearly instead of compounding.
Graduated payment schedule: step compounding base · case 05
Later-year payments grow linearly instead of compounding.
Graduated payment schedule: year boundary · case 01
Payments step up in the twelfth month of each year.
Graduated payment schedule: year boundary · case 02
Payments step up in the twelfth month of each year.
Graduated payment schedule: year boundary · case 03
Payments step up in the twelfth month of each year.
Graduated payment schedule: year boundary · case 04
Payments step up in the twelfth month of each year.
Graduated payment schedule: year boundary · case 05
Payments step up in the twelfth month of each year.
Graduated payment schedule: re-level term · case 01
The fixed payment after the graduated years leaves most of the balance unpaid at maturity.
Graduated payment schedule: re-level term · case 02
The fixed payment after the graduated years leaves most of the balance unpaid at maturity.
Graduated payment schedule: re-level term · case 03
The fixed payment after the graduated years leaves most of the balance unpaid at maturity.
Graduated payment schedule: re-level term · case 04
The fixed payment after the graduated years leaves most of the balance unpaid at maturity.
Graduated payment schedule: re-level term · case 05
The fixed payment after the graduated years leaves most of the balance unpaid at maturity.
Graduated payment schedule: step count limit · case 01
The schedule re-levels one year early and skips the last step.
Graduated payment schedule: step count limit · case 02
The schedule re-levels one year early and skips the last step.
Graduated payment schedule: step count limit · case 03
The schedule re-levels one year early and skips the last step.
Graduated payment schedule: step count limit · case 04
The schedule re-levels one year early and skips the last step.
Graduated payment schedule: step count limit · case 05
The schedule re-levels one year early and skips the last step.
Graduated payment schedule: peak tracking · case 01
Peak balance disclosures report only the original principal.
Graduated payment schedule: peak tracking · case 02
Peak balance disclosures report only the original principal.
Graduated payment schedule: peak tracking · case 03
Peak balance disclosures report only the original principal.
Graduated payment schedule: peak tracking · case 04
Peak balance disclosures report only the original principal.
Graduated payment schedule: peak tracking · case 05
Peak balance disclosures report only the original principal.
Social security wage-base withholding: section 125 wage reduction · case 01
Employees contributing to a 401(k) have too little social security withheld.
Social security wage-base withholding: section 125 wage reduction · case 02
Employees contributing to a 401(k) have too little social security withheld.
Social security wage-base withholding: section 125 wage reduction · case 03
Employees contributing to a 401(k) have too little social security withheld.
Social security wage-base withholding: section 125 wage reduction · case 04
Employees contributing to a 401(k) have too little social security withheld.
Social security wage-base withholding: section 125 wage reduction · case 05
Employees contributing to a 401(k) have too little social security withheld.
Social security wage-base withholding: reported tips inclusion · case 01
Tipped employees are under-withheld because reported tips never reach social security wages.
Social security wage-base withholding: reported tips inclusion · case 02
Tipped employees are under-withheld because reported tips never reach social security wages.
Social security wage-base withholding: reported tips inclusion · case 03
Tipped employees are under-withheld because reported tips never reach social security wages.
Social security wage-base withholding: reported tips inclusion · case 04
Tipped employees are under-withheld because reported tips never reach social security wages.
Social security wage-base withholding: reported tips inclusion · case 05
Tipped employees are under-withheld because reported tips never reach social security wages.
Social security wage-base withholding: remaining wage-base room · case 01
Employees already past the wage base get a negative taxable amount and a negative tax (a refund) on the paycheck.
Social security wage-base withholding: remaining wage-base room · case 02
Employees already past the wage base get a negative taxable amount and a negative tax (a refund) on the paycheck.
Social security wage-base withholding: remaining wage-base room · case 03
Employees already past the wage base get a negative taxable amount and a negative tax (a refund) on the paycheck.
Social security wage-base withholding: remaining wage-base room · case 04
Employees already past the wage base get a negative taxable amount and a negative tax (a refund) on the paycheck.
Social security wage-base withholding: remaining wage-base room · case 05
Employees already past the wage base get a negative taxable amount and a negative tax (a refund) on the paycheck.
Social security wage-base withholding: taxable wage cap · case 01
Paychecks that cross the wage base withhold on the full paycheck instead of only the portion below the base.
Social security wage-base withholding: taxable wage cap · case 02
Paychecks that cross the wage base withhold on the full paycheck instead of only the portion below the base.
Social security wage-base withholding: taxable wage cap · case 03
Paychecks that cross the wage base withhold on the full paycheck instead of only the portion below the base.
Social security wage-base withholding: taxable wage cap · case 04
Paychecks that cross the wage base withhold on the full paycheck instead of only the portion below the base.
Social security wage-base withholding: taxable wage cap · case 05
Paychecks that cross the wage base withhold on the full paycheck instead of only the portion below the base.
Social security wage-base withholding: cent rounding of tax · case 01
Withholding is a cent short whenever 6.2% of taxable wages has a fractional cent of one half or more.
Social security wage-base withholding: cent rounding of tax · case 02
Withholding is a cent short whenever 6.2% of taxable wages has a fractional cent of one half or more.
Social security wage-base withholding: cent rounding of tax · case 03
Withholding is a cent short whenever 6.2% of taxable wages has a fractional cent of one half or more.
Social security wage-base withholding: cent rounding of tax · case 04
Withholding is a cent short whenever 6.2% of taxable wages has a fractional cent of one half or more.
Social security wage-base withholding: cent rounding of tax · case 05
Withholding is a cent short whenever 6.2% of taxable wages has a fractional cent of one half or more.
Additional Medicare withholding threshold: threshold crossing portion · case 01
After the threshold is crossed, each paycheck applies the extra 0.9% to all year-to-date excess wages again.
Additional Medicare withholding threshold: threshold crossing portion · case 02
After the threshold is crossed, each paycheck applies the extra 0.9% to all year-to-date excess wages again.
Additional Medicare withholding threshold: threshold crossing portion · case 03
After the threshold is crossed, each paycheck applies the extra 0.9% to all year-to-date excess wages again.
Additional Medicare withholding threshold: threshold crossing portion · case 04
After the threshold is crossed, each paycheck applies the extra 0.9% to all year-to-date excess wages again.
Additional Medicare withholding threshold: threshold crossing portion · case 05
After the threshold is crossed, each paycheck applies the extra 0.9% to all year-to-date excess wages again.
Additional Medicare withholding threshold: prior excess measurement · case 01
Employees below the threshold get additional Medicare wages larger than the paycheck itself.
Additional Medicare withholding threshold: prior excess measurement · case 02
Employees below the threshold get additional Medicare wages larger than the paycheck itself.
Additional Medicare withholding threshold: prior excess measurement · case 03
Employees below the threshold get additional Medicare wages larger than the paycheck itself.
Additional Medicare withholding threshold: prior excess measurement · case 04
Employees below the threshold get additional Medicare wages larger than the paycheck itself.
Additional Medicare withholding threshold: prior excess measurement · case 05
Employees below the threshold get additional Medicare wages larger than the paycheck itself.
Additional Medicare withholding threshold: separately rounded components · case 01
The total Medicare line is off by a cent from the sum of its two printed components.
Additional Medicare withholding threshold: separately rounded components · case 02
The total Medicare line is off by a cent from the sum of its two printed components.
Additional Medicare withholding threshold: separately rounded components · case 03
The total Medicare line is off by a cent from the sum of its two printed components.
Additional Medicare withholding threshold: separately rounded components · case 04
The total Medicare line is off by a cent from the sum of its two printed components.
Additional Medicare withholding threshold: separately rounded components · case 05
The total Medicare line is off by a cent from the sum of its two printed components.
Additional Medicare withholding threshold: additional rate unit · case 01
Additional Medicare withholding is ten times too large once the threshold is crossed.
Additional Medicare withholding threshold: additional rate unit · case 02
Additional Medicare withholding is ten times too large once the threshold is crossed.
Additional Medicare withholding threshold: additional rate unit · case 03
Additional Medicare withholding is ten times too large once the threshold is crossed.
Additional Medicare withholding threshold: additional rate unit · case 04
Additional Medicare withholding is ten times too large once the threshold is crossed.
Additional Medicare withholding threshold: additional rate unit · case 05
Additional Medicare withholding is ten times too large once the threshold is crossed.
Annualized percentage-method withholding: bracket slice upper bound · case 01
Employees whose income reaches a higher bracket are withheld far too much because lower brackets tax the whole income.
Annualized percentage-method withholding: bracket slice upper bound · case 02
Employees whose income reaches a higher bracket are withheld far too much because lower brackets tax the whole income.
Annualized percentage-method withholding: bracket slice upper bound · case 03
Employees whose income reaches a higher bracket are withheld far too much because lower brackets tax the whole income.
Annualized percentage-method withholding: bracket slice upper bound · case 04
Employees whose income reaches a higher bracket are withheld far too much because lower brackets tax the whole income.
Annualized percentage-method withholding: bracket slice upper bound · case 05
Employees whose income reaches a higher bracket are withheld far too much because lower brackets tax the whole income.
Annualized percentage-method withholding: marginal slice accumulation · case 01
Withholding jumps discontinuously when income crosses a bracket, taxing all income at the top reached rate.
Annualized percentage-method withholding: marginal slice accumulation · case 02
Withholding jumps discontinuously when income crosses a bracket, taxing all income at the top reached rate.
Annualized percentage-method withholding: marginal slice accumulation · case 03
Withholding jumps discontinuously when income crosses a bracket, taxing all income at the top reached rate.
Annualized percentage-method withholding: marginal slice accumulation · case 04
Withholding jumps discontinuously when income crosses a bracket, taxing all income at the top reached rate.
Annualized percentage-method withholding: marginal slice accumulation · case 05
Withholding jumps discontinuously when income crosses a bracket, taxing all income at the top reached rate.
Annualized percentage-method withholding: de-annualization rounding stage · case 01
Per-period withholding drifts by several cents from the exact annualized result.
Annualized percentage-method withholding: de-annualization rounding stage · case 02
Per-period withholding drifts by several cents from the exact annualized result.
Annualized percentage-method withholding: de-annualization rounding stage · case 03
Per-period withholding drifts by several cents from the exact annualized result.
Annualized percentage-method withholding: de-annualization rounding stage · case 04
Per-period withholding drifts by several cents from the exact annualized result.
Annualized percentage-method withholding: de-annualization rounding stage · case 05
Per-period withholding drifts by several cents from the exact annualized result.
INSPECTABLE BY DESIGN
Every result has a runnable source.
Runnable implementations with recorded outputs, source hashes, and explicit contracts. Related variants share a failure mechanism and belong together in evaluation splits.
Read the methodology ↗