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
Multiset selection count · case 01
Distinct-subset counting forbids permitted repeats.
Multiset selection count · case 02
Distinct-subset counting forbids permitted repeats.
Multiset selection count · case 03
Distinct-subset counting forbids permitted repeats.
Multiset selection count · case 04
Distinct-subset counting forbids permitted repeats.
Multiset selection count · case 05
Distinct-subset counting forbids permitted repeats.
Binary subsets count · case 01
Squaring the size does not enumerate include/exclude choices.
Binary subsets count · case 02
Squaring the size does not enumerate include/exclude choices.
Binary subsets count · case 03
Squaring the size does not enumerate include/exclude choices.
Binary subsets count · case 04
Squaring the size does not enumerate include/exclude choices.
Binary subsets count · case 05
Squaring the size does not enumerate include/exclude choices.
Nonempty subsets count · case 01
The empty subset is included.
Nonempty subsets count · case 02
The empty subset is included.
Nonempty subsets count · case 03
The empty subset is included.
Nonempty subsets count · case 04
The empty subset is included.
Nonempty subsets count · case 05
The empty subset is included.
Proper nonempty subsets count · case 01
The whole set is retained among proper subsets.
Proper nonempty subsets count · case 02
The whole set is retained among proper subsets.
Proper nonempty subsets count · case 03
The whole set is retained among proper subsets.
Proper nonempty subsets count · case 04
The whole set is retained among proper subsets.
Proper nonempty subsets count · case 05
The whole set is retained among proper subsets.
Unordered pair count · case 01
Self pairs and symmetric copies are included.
Unordered pair count · case 02
Self pairs and symmetric copies are included.
Unordered pair count · case 03
Self pairs and symmetric copies are included.
Unordered pair count · case 04
Self pairs and symmetric copies are included.
Unordered pair count · case 05
Self pairs and symmetric copies are included.
Prime length necklace colorings · case 01
Dividing all words by the length mishandles constant words with smaller rotation orbits.
Prime length necklace colorings · case 02
Dividing all words by the length mishandles constant words with smaller rotation orbits.
Prime length necklace colorings · case 03
Dividing all words by the length mishandles constant words with smaller rotation orbits.
Prime length necklace colorings · case 04
Dividing all words by the length mishandles constant words with smaller rotation orbits.
Prime length necklace colorings · case 05
Dividing all words by the length mishandles constant words with smaller rotation orbits.
Circular labelled arrangements · case 01
Rotations are treated as different circular arrangements.
Circular labelled arrangements · case 02
Rotations are treated as different circular arrangements.
Circular labelled arrangements · case 03
Rotations are treated as different circular arrangements.
Circular labelled arrangements · case 04
Rotations are treated as different circular arrangements.
Circular labelled arrangements · case 05
Rotations are treated as different circular arrangements.
Polygon diagonal count · case 01
Polygon sides are included as diagonals.
Polygon diagonal count · case 02
Polygon sides are included as diagonals.
Polygon diagonal count · case 03
Polygon sides are included as diagonals.
Polygon diagonal count · case 04
Polygon sides are included as diagonals.
Polygon diagonal count · case 05
Polygon sides are included as diagonals.
Rectangular grid cell rectangle count · case 01
Only unit rectangles are counted.
Rectangular grid cell rectangle count · case 02
Only unit rectangles are counted.
Rectangular grid cell rectangle count · case 03
Only unit rectangles are counted.
Rectangular grid cell rectangle count · case 04
Only unit rectangles are counted.
Rectangular grid cell rectangle count · case 05
Only unit rectangles are counted.
Rectangular grid all square count · case 01
Only the unit-square placements are counted.
Rectangular grid all square count · case 02
Only the unit-square placements are counted.
Rectangular grid all square count · case 03
Only the unit-square placements are counted.
Rectangular grid all square count · case 04
Only the unit-square placements are counted.
Rectangular grid all square count · case 05
Only the unit-square placements are counted.
Lattice monotone path count · case 01
The path count is confused with grid area.
Lattice monotone path count · case 02
The path count is confused with grid area.
Lattice monotone path count · case 03
The path count is confused with grid area.
Lattice monotone path count · case 04
The path count is confused with grid area.
Lattice monotone path count · case 05
The path count is confused with grid area.
Catalan balanced parentheses · case 01
Balanced totals are accepted without the prefix-balance constraint.
Catalan balanced parentheses · case 02
Balanced totals are accepted without the prefix-balance constraint.
Catalan balanced parentheses · case 03
Balanced totals are accepted without the prefix-balance constraint.
Catalan balanced parentheses · case 04
Balanced totals are accepted without the prefix-balance constraint.
Catalan balanced parentheses · case 05
Balanced totals are accepted without the prefix-balance constraint.
Derangement count · case 01
Removing only the identity leaves permutations with other fixed points.
Derangement count · case 02
Removing only the identity leaves permutations with other fixed points.
Derangement count · case 03
Removing only the identity leaves permutations with other fixed points.
Derangement count · case 04
Removing only the identity leaves permutations with other fixed points.
Derangement count · case 05
Removing only the identity leaves permutations with other fixed points.
Onto function count · case 01
All functions are accepted without requiring every target.
Onto function count · case 02
All functions are accepted without requiring every target.
Onto function count · case 03
All functions are accepted without requiring every target.
Onto function count · case 04
All functions are accepted without requiring every target.
Onto function count · case 05
All functions are accepted without requiring every target.
Stirling second kind · case 01
Labelled assignments include empty blocks and distinguish block names.
Stirling second kind · case 02
Labelled assignments include empty blocks and distinguish block names.
Stirling second kind · case 03
Labelled assignments include empty blocks and distinguish block names.
Stirling second kind · case 04
Labelled assignments include empty blocks and distinguish block names.
Stirling second kind · case 05
Labelled assignments include empty blocks and distinguish block names.
Weak composition count · case 01
A positive-composition formula excludes zero components.
Weak composition count · case 02
A positive-composition formula excludes zero components.
Weak composition count · case 03
A positive-composition formula excludes zero components.
Weak composition count · case 04
A positive-composition formula excludes zero components.
Weak composition count · case 05
A positive-composition formula excludes zero components.
Positive composition count · case 01
Zero components are admitted in a positive composition.
Positive composition count · case 02
Zero components are admitted in a positive composition.
Positive composition count · case 03
Zero components are admitted in a positive composition.
Positive composition count · case 04
Zero components are admitted in a positive composition.
Positive composition count · case 05
Zero components are admitted in a positive composition.
Multinomial word count · case 01
Repeated symbols are treated as separately labelled.
Multinomial word count · case 02
Repeated symbols are treated as separately labelled.
Multinomial word count · case 03
Repeated symbols are treated as separately labelled.
Multinomial word count · case 04
Repeated symbols are treated as separately labelled.
Multinomial word count · case 05
Repeated symbols are treated as separately labelled.
Exact heads coin count · case 01
Outcomes with other head counts are included.
Exact heads coin count · case 02
Outcomes with other head counts are included.
Exact heads coin count · case 03
Outcomes with other head counts are included.
Exact heads coin count · case 04
Outcomes with other head counts are included.
Exact heads coin count · case 05
Outcomes with other head counts are included.
Binomial probability rational · case 01
One arrangement is mistaken for all arrangements with k successes.
Binomial probability rational · case 02
One arrangement is mistaken for all arrangements with k successes.
Binomial probability rational · case 03
One arrangement is mistaken for all arrangements with k successes.
Binomial probability rational · case 04
One arrangement is mistaken for all arrangements with k successes.
Binomial probability rational · case 05
One arrangement is mistaken for all arrangements with k successes.
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 ↗