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
Charm pricing subtracts a cent from the ceiling · case 01
A converted price of exactly 12.00 is listed at 11.99, below the converted value.
Charm pricing subtracts a cent from the ceiling · case 02
A converted price of exactly 12.00 is listed at 11.99, below the converted value.
Charm pricing subtracts a cent from the ceiling · case 03
A converted price of exactly 12.00 is listed at 11.99, below the converted value.
Charm pricing subtracts a cent from the ceiling · case 04
A converted price of exactly 12.00 is listed at 11.99, below the converted value.
Charm pricing subtracts a cent from the ceiling · case 05
A converted price of exactly 12.00 is listed at 11.99, below the converted value.
A converted value already on a charm price is bumped to the next one · case 01
11.99 converts to 12.99 even though 11.99 is already a valid charm price.
A converted value already on a charm price is bumped to the next one · case 02
11.99 converts to 12.99 even though 11.99 is already a valid charm price.
A converted value already on a charm price is bumped to the next one · case 03
11.99 converts to 12.99 even though 11.99 is already a valid charm price.
A converted value already on a charm price is bumped to the next one · case 04
11.99 converts to 12.99 even though 11.99 is already a valid charm price.
A converted value already on a charm price is bumped to the next one · case 05
11.99 converts to 12.99 even though 11.99 is already a valid charm price.
Yen prices receive a decimal .99 charm ending · case 01
Yen shelf prices appear as 1234.99.
Yen prices receive a decimal .99 charm ending · case 02
Yen shelf prices appear as 1234.99.
Yen prices receive a decimal .99 charm ending · case 03
Yen shelf prices appear as 1234.99.
Yen prices receive a decimal .99 charm ending · case 04
Yen shelf prices appear as 1234.99.
Yen prices receive a decimal .99 charm ending · case 05
Yen shelf prices appear as 1234.99.
The converted price is rounded to cents before charm pricing · case 01
A converted value of 11.994 is listed at 11.99, below the converted amount.
The converted price is rounded to cents before charm pricing · case 02
A converted value of 11.994 is listed at 11.99, below the converted amount.
The converted price is rounded to cents before charm pricing · case 03
A converted value of 11.994 is listed at 11.99, below the converted amount.
The converted price is rounded to cents before charm pricing · case 04
A converted value of 11.994 is listed at 11.99, below the converted amount.
The converted price is rounded to cents before charm pricing · case 05
A converted value of 11.994 is listed at 11.99, below the converted amount.
Every currency's deposit rate is scaled on a 360-day basis · case 01
Sterling and Canadian-dollar forwards are mispriced by the basis difference.
Every currency's deposit rate is scaled on a 360-day basis · case 02
Sterling and Canadian-dollar forwards are mispriced by the basis difference.
Every currency's deposit rate is scaled on a 360-day basis · case 03
Sterling and Canadian-dollar forwards are mispriced by the basis difference.
Every currency's deposit rate is scaled on a 360-day basis · case 04
Sterling and Canadian-dollar forwards are mispriced by the basis difference.
Every currency's deposit rate is scaled on a 360-day basis · case 05
Sterling and Canadian-dollar forwards are mispriced by the basis difference.
The base and quote deposit rates are swapped in the parity formula · case 01
A higher-yielding quote currency produces forward discount points instead of premium points.
The base and quote deposit rates are swapped in the parity formula · case 02
A higher-yielding quote currency produces forward discount points instead of premium points.
The base and quote deposit rates are swapped in the parity formula · case 03
A higher-yielding quote currency produces forward discount points instead of premium points.
The base and quote deposit rates are swapped in the parity formula · case 04
A higher-yielding quote currency produces forward discount points instead of premium points.
The base and quote deposit rates are swapped in the parity formula · case 05
A higher-yielding quote currency produces forward discount points instead of premium points.
Forward points are derived from the rounded outright · case 01
Points disagree in the second decimal with points computed from the exact forward.
Forward points are derived from the rounded outright · case 02
Points disagree in the second decimal with points computed from the exact forward.
Forward points are derived from the rounded outright · case 03
Points disagree in the second decimal with points computed from the exact forward.
Forward points are derived from the rounded outright · case 04
Points disagree in the second decimal with points computed from the exact forward.
Forward points are derived from the rounded outright · case 05
Points disagree in the second decimal with points computed from the exact forward.
JPY-quoted forwards use a four-decimal pip · case 01
USDJPY forward points are a hundred times too large.
JPY-quoted forwards use a four-decimal pip · case 02
USDJPY forward points are a hundred times too large.
JPY-quoted forwards use a four-decimal pip · case 03
USDJPY forward points are a hundred times too large.
JPY-quoted forwards use a four-decimal pip · case 04
USDJPY forward points are a hundred times too large.
JPY-quoted forwards use a four-decimal pip · case 05
USDJPY forward points are a hundred times too large.
The whole income is taxed at the rate of its highest bracket · case 01
Crossing a threshold by one dollar raises tax on every dollar of income.
The whole income is taxed at the rate of its highest bracket · case 02
Crossing a threshold by one dollar raises tax on every dollar of income.
The whole income is taxed at the rate of its highest bracket · case 03
Crossing a threshold by one dollar raises tax on every dollar of income.
The whole income is taxed at the rate of its highest bracket · case 04
Crossing a threshold by one dollar raises tax on every dollar of income.
The whole income is taxed at the rate of its highest bracket · case 05
Crossing a threshold by one dollar raises tax on every dollar of income.
Each bracket rate is applied to income measured from zero · case 01
Tax in the second bracket also re-taxes the first bracket's income.
Each bracket rate is applied to income measured from zero · case 02
Tax in the second bracket also re-taxes the first bracket's income.
Each bracket rate is applied to income measured from zero · case 03
Tax in the second bracket also re-taxes the first bracket's income.
Each bracket rate is applied to income measured from zero · case 04
Tax in the second bracket also re-taxes the first bracket's income.
Each bracket rate is applied to income measured from zero · case 05
Tax in the second bracket also re-taxes the first bracket's income.
Each bracket slice is rounded to cents before summing · case 01
Totals differ by a cent from the exact schedule when several slices carry half-cents.
Each bracket slice is rounded to cents before summing · case 02
Totals differ by a cent from the exact schedule when several slices carry half-cents.
Each bracket slice is rounded to cents before summing · case 03
Totals differ by a cent from the exact schedule when several slices carry half-cents.
Each bracket slice is rounded to cents before summing · case 04
Totals differ by a cent from the exact schedule when several slices carry half-cents.
Each bracket slice is rounded to cents before summing · case 05
Totals differ by a cent from the exact schedule when several slices carry half-cents.
A schedule with non-increasing thresholds is accepted · case 01
A mis-keyed bracket table silently produces a tax figure.
A schedule with non-increasing thresholds is accepted · case 02
A mis-keyed bracket table silently produces a tax figure.
A schedule with non-increasing thresholds is accepted · case 03
A mis-keyed bracket table silently produces a tax figure.
A schedule with non-increasing thresholds is accepted · case 04
A mis-keyed bracket table silently produces a tax figure.
A schedule with non-increasing thresholds is accepted · case 05
A mis-keyed bracket table silently produces a tax figure.
Income above the last threshold escapes tax · case 01
High earners pay the same tax as someone exactly at the final threshold.
Income above the last threshold escapes tax · case 02
High earners pay the same tax as someone exactly at the final threshold.
Income above the last threshold escapes tax · case 03
High earners pay the same tax as someone exactly at the final threshold.
Income above the last threshold escapes tax · case 04
High earners pay the same tax as someone exactly at the final threshold.
Income above the last threshold escapes tax · case 05
High earners pay the same tax as someone exactly at the final threshold.
The final tax is converted to cents through binary floating point · case 01
A liability of 4.60 is reported as 459 cents.
The final tax is converted to cents through binary floating point · case 02
A liability of 4.60 is reported as 459 cents.
The final tax is converted to cents through binary floating point · case 03
A liability of 4.60 is reported as 459 cents.
The final tax is converted to cents through binary floating point · case 04
A liability of 4.60 is reported as 459 cents.
The final tax is converted to cents through binary floating point · case 05
A liability of 4.60 is reported as 459 cents.
The smaller of standard and itemized deductions is taken · case 01
A taxpayer with no itemized deductions deducts nothing.
The smaller of standard and itemized deductions is taken · case 02
A taxpayer with no itemized deductions deducts nothing.
The smaller of standard and itemized deductions is taken · case 03
A taxpayer with no itemized deductions deducts nothing.
The smaller of standard and itemized deductions is taken · case 04
A taxpayer with no itemized deductions deducts nothing.
The smaller of standard and itemized deductions is taken · case 05
A taxpayer with no itemized deductions deducts nothing.
Taxable income goes negative when deductions exceed gross income · case 01
A low-income return shows negative taxable income that offsets other lines.
Taxable income goes negative when deductions exceed gross income · case 02
A low-income return shows negative taxable income that offsets other lines.
Taxable income goes negative when deductions exceed gross income · case 03
A low-income return shows negative taxable income that offsets other lines.
Taxable income goes negative when deductions exceed gross income · case 04
A low-income return shows negative taxable income that offsets other lines.
Taxable income goes negative when deductions exceed gross income · case 05
A low-income return shows negative taxable income that offsets other lines.
Head-of-household filers receive the married additional amount · case 01
An elderly head of household deducts 400 less than entitled.
Head-of-household filers receive the married additional amount · case 02
An elderly head of household deducts 400 less than entitled.
Head-of-household filers receive the married additional amount · case 03
An elderly head of household deducts 400 less than entitled.
Head-of-household filers receive the married additional amount · case 04
An elderly head of household deducts 400 less than entitled.
Head-of-household filers receive the married additional amount · case 05
An elderly head of household deducts 400 less than entitled.
A dependent's standard deduction is not capped at the ordinary amount · case 01
A dependent with high earnings deducts more than the regular standard deduction.
A dependent's standard deduction is not capped at the ordinary amount · case 02
A dependent with high earnings deducts more than the regular standard deduction.
A dependent's standard deduction is not capped at the ordinary amount · case 03
A dependent with high earnings deducts more than the regular standard deduction.
A dependent's standard deduction is not capped at the ordinary amount · case 04
A dependent with high earnings deducts more than the regular standard deduction.
A dependent's standard deduction is not capped at the ordinary amount · case 05
A dependent with high earnings deducts more than the regular standard deduction.
A separate filer keeps the standard deduction while the spouse itemizes · case 01
Married-filing-separately returns claim a standard deduction the rules deny.
A separate filer keeps the standard deduction while the spouse itemizes · case 02
Married-filing-separately returns claim a standard deduction the rules deny.
A separate filer keeps the standard deduction while the spouse itemizes · case 03
Married-filing-separately returns claim a standard deduction the rules deny.
A separate filer keeps the standard deduction while the spouse itemizes · case 04
Married-filing-separately returns claim a standard deduction the rules deny.
A separate filer keeps the standard deduction while the spouse itemizes · case 05
Married-filing-separately returns claim a standard deduction the rules deny.
The dependent cap also truncates the age and blindness additions · case 01
An elderly dependent loses the additional standard deduction.
The dependent cap also truncates the age and blindness additions · case 02
An elderly dependent loses the additional standard deduction.
The dependent cap also truncates the age and blindness additions · case 03
An elderly dependent loses the additional standard deduction.
The dependent cap also truncates the age and blindness additions · case 04
An elderly dependent loses the additional standard deduction.
The dependent cap also truncates the age and blindness additions · case 05
An elderly dependent loses the additional standard deduction.
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 ↗