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
Combinations respect positional order · case 01
The operation returns a result or retained state that violates this contract: Return length-r combinations of input positions, preserving input order within tuples and retaining duplicate-valued tuples.
Combinations respect positional order · case 02
The operation returns a result or retained state that violates this contract: Return length-r combinations of input positions, preserving input order within tuples and retaining duplicate-valued tuples.
Combinations respect positional order · case 03
The operation returns a result or retained state that violates this contract: Return length-r combinations of input positions, preserving input order within tuples and retaining duplicate-valued tuples.
Combinations respect positional order · case 04
The operation returns a result or retained state that violates this contract: Return length-r combinations of input positions, preserving input order within tuples and retaining duplicate-valued tuples.
Combinations respect positional order · case 05
The operation returns a result or retained state that violates this contract: Return length-r combinations of input positions, preserving input order within tuples and retaining duplicate-valued tuples.
Combinations with replacement allows reused position · case 01
The operation returns a result or retained state that violates this contract: Return length-r combinations with replacement, allowing the same input position repeatedly.
Combinations with replacement allows reused position · case 02
The operation returns a result or retained state that violates this contract: Return length-r combinations with replacement, allowing the same input position repeatedly.
Combinations with replacement allows reused position · case 03
The operation returns a result or retained state that violates this contract: Return length-r combinations with replacement, allowing the same input position repeatedly.
Combinations with replacement allows reused position · case 04
The operation returns a result or retained state that violates this contract: Return length-r combinations with replacement, allowing the same input position repeatedly.
Combinations with replacement allows reused position · case 05
The operation returns a result or retained state that violates this contract: Return length-r combinations with replacement, allowing the same input position repeatedly.
Zip longest distinguishes real none · case 01
The operation returns a result or retained state that violates this contract: Zip to exhaustion of both inputs and fill missing positions with a distinct string marker; present None is retained.
Zip longest distinguishes real none · case 02
The operation returns a result or retained state that violates this contract: Zip to exhaustion of both inputs and fill missing positions with a distinct string marker; present None is retained.
Zip longest distinguishes real none · case 03
The operation returns a result or retained state that violates this contract: Zip to exhaustion of both inputs and fill missing positions with a distinct string marker; present None is retained.
Zip longest distinguishes real none · case 04
The operation returns a result or retained state that violates this contract: Zip to exhaustion of both inputs and fill missing positions with a distinct string marker; present None is retained.
Zip longest distinguishes real none · case 05
The operation returns a result or retained state that violates this contract: Zip to exhaustion of both inputs and fill missing positions with a distinct string marker; present None is retained.
Map is lazy before consumption · case 01
The operation returns a result or retained state that violates this contract: Constructing map must not invoke callbacks; taking n results invokes only those callbacks. Return [calls before,calls after,results].
Map is lazy before consumption · case 02
The operation returns a result or retained state that violates this contract: Constructing map must not invoke callbacks; taking n results invokes only those callbacks. Return [calls before,calls after,results].
Map is lazy before consumption · case 03
The operation returns a result or retained state that violates this contract: Constructing map must not invoke callbacks; taking n results invokes only those callbacks. Return [calls before,calls after,results].
Map is lazy before consumption · case 04
The operation returns a result or retained state that violates this contract: Constructing map must not invoke callbacks; taking n results invokes only those callbacks. Return [calls before,calls after,results].
Map is lazy before consumption · case 05
The operation returns a result or retained state that violates this contract: Constructing map must not invoke callbacks; taking n results invokes only those callbacks. Return [calls before,calls after,results].
Filter lazily consumes through first match · case 01
The operation returns a result or retained state that violates this contract: Take the first value equal to sentinel from a filtered iterator; return [match or missing,unconsumed source].
Filter lazily consumes through first match · case 02
The operation returns a result or retained state that violates this contract: Take the first value equal to sentinel from a filtered iterator; return [match or missing,unconsumed source].
Filter lazily consumes through first match · case 03
The operation returns a result or retained state that violates this contract: Take the first value equal to sentinel from a filtered iterator; return [match or missing,unconsumed source].
Filter lazily consumes through first match · case 04
The operation returns a result or retained state that violates this contract: Take the first value equal to sentinel from a filtered iterator; return [match or missing,unconsumed source].
Filter lazily consumes through first match · case 05
The operation returns a result or retained state that violates this contract: Take the first value equal to sentinel from a filtered iterator; return [match or missing,unconsumed source].
Any short circuit consumption · case 01
The operation returns a result or retained state that violates this contract: Apply any to a one-pass stream and return [truth result,unconsumed suffix].
Any short circuit consumption · case 02
The operation returns a result or retained state that violates this contract: Apply any to a one-pass stream and return [truth result,unconsumed suffix].
Any short circuit consumption · case 03
The operation returns a result or retained state that violates this contract: Apply any to a one-pass stream and return [truth result,unconsumed suffix].
Any short circuit consumption · case 04
The operation returns a result or retained state that violates this contract: Apply any to a one-pass stream and return [truth result,unconsumed suffix].
Any short circuit consumption · case 05
The operation returns a result or retained state that violates this contract: Apply any to a one-pass stream and return [truth result,unconsumed suffix].
All short circuit consumption · case 01
The operation returns a result or retained state that violates this contract: Apply all to a one-pass stream and return [truth result,unconsumed suffix]; the empty result is true.
All short circuit consumption · case 02
The operation returns a result or retained state that violates this contract: Apply all to a one-pass stream and return [truth result,unconsumed suffix]; the empty result is true.
All short circuit consumption · case 03
The operation returns a result or retained state that violates this contract: Apply all to a one-pass stream and return [truth result,unconsumed suffix]; the empty result is true.
All short circuit consumption · case 04
The operation returns a result or retained state that violates this contract: Apply all to a one-pass stream and return [truth result,unconsumed suffix]; the empty result is true.
All short circuit consumption · case 05
The operation returns a result or retained state that violates this contract: Apply all to a one-pass stream and return [truth result,unconsumed suffix]; the empty result is true.
Enumerate offset affects index not source · case 01
The operation returns a result or retained state that violates this contract: Enumerate the entire stream starting at the supplied counter value; offset does not skip source values.
Enumerate offset affects index not source · case 02
The operation returns a result or retained state that violates this contract: Enumerate the entire stream starting at the supplied counter value; offset does not skip source values.
Enumerate offset affects index not source · case 03
The operation returns a result or retained state that violates this contract: Enumerate the entire stream starting at the supplied counter value; offset does not skip source values.
Enumerate offset affects index not source · case 04
The operation returns a result or retained state that violates this contract: Enumerate the entire stream starting at the supplied counter value; offset does not skip source values.
Enumerate offset affects index not source · case 05
The operation returns a result or retained state that violates this contract: Enumerate the entire stream starting at the supplied counter value; offset does not skip source values.
Callable iterator misses an equal but distinct sentinel · case 01
An equal sentinel stored in another object fails to stop iteration.
Callable iterator misses an equal but distinct sentinel · case 02
An equal sentinel stored in another object fails to stop iteration.
Callable iterator misses an equal but distinct sentinel · case 03
An equal sentinel stored in another object fails to stop iteration.
Callable iterator misses an equal but distinct sentinel · case 04
An equal sentinel stored in another object fails to stop iteration.
Callable iterator misses an equal but distinct sentinel · case 05
An equal sentinel stored in another object fails to stop iteration.
Iterator membership consumes through match · case 01
The operation returns a result or retained state that violates this contract: Membership testing on a one-pass iterator consumes through the matched item and leaves only later items.
Iterator membership consumes through match · case 02
The operation returns a result or retained state that violates this contract: Membership testing on a one-pass iterator consumes through the matched item and leaves only later items.
Iterator membership consumes through match · case 03
The operation returns a result or retained state that violates this contract: Membership testing on a one-pass iterator consumes through the matched item and leaves only later items.
Iterator membership consumes through match · case 04
The operation returns a result or retained state that violates this contract: Membership testing on a one-pass iterator consumes through the matched item and leaves only later items.
Iterator membership consumes through match · case 05
The operation returns a result or retained state that violates this contract: Membership testing on a one-pass iterator consumes through the matched item and leaves only later items.
Iterator second pass is exhausted · case 01
The operation returns a result or retained state that violates this contract: Materializing a one-pass iterator exhausts it; a second materialization is empty.
Iterator second pass is exhausted · case 02
The operation returns a result or retained state that violates this contract: Materializing a one-pass iterator exhausts it; a second materialization is empty.
Iterator second pass is exhausted · case 03
The operation returns a result or retained state that violates this contract: Materializing a one-pass iterator exhausts it; a second materialization is empty.
Iterator second pass is exhausted · case 04
The operation returns a result or retained state that violates this contract: Materializing a one-pass iterator exhausts it; a second materialization is empty.
Iterator second pass is exhausted · case 05
The operation returns a result or retained state that violates this contract: Materializing a one-pass iterator exhausts it; a second materialization is empty.
Islice step consumes stop prefix · case 01
The operation returns a result or retained state that violates this contract: Exhausting islice(start,stop,step) consumes through stop regardless of the last yielded position; return [yielded,remaining].
Islice step consumes stop prefix · case 02
The operation returns a result or retained state that violates this contract: Exhausting islice(start,stop,step) consumes through stop regardless of the last yielded position; return [yielded,remaining].
Islice step consumes stop prefix · case 03
The operation returns a result or retained state that violates this contract: Exhausting islice(start,stop,step) consumes through stop regardless of the last yielded position; return [yielded,remaining].
Islice step consumes stop prefix · case 04
The operation returns a result or retained state that violates this contract: Exhausting islice(start,stop,step) consumes through stop regardless of the last yielded position; return [yielded,remaining].
Islice step consumes stop prefix · case 05
The operation returns a result or retained state that violates this contract: Exhausting islice(start,stop,step) consumes through stop regardless of the last yielded position; return [yielded,remaining].
Counter subtract retains nonpositive counts · case 01
The operation returns a result or retained state that violates this contract: Subtract right counts from left counts and retain zero and negative entries in insertion order.
Counter subtract retains nonpositive counts · case 02
The operation returns a result or retained state that violates this contract: Subtract right counts from left counts and retain zero and negative entries in insertion order.
Counter subtract retains nonpositive counts · case 03
The operation returns a result or retained state that violates this contract: Subtract right counts from left counts and retain zero and negative entries in insertion order.
Counter subtract retains nonpositive counts · case 04
The operation returns a result or retained state that violates this contract: Subtract right counts from left counts and retain zero and negative entries in insertion order.
Counter subtract retains nonpositive counts · case 05
The operation returns a result or retained state that violates this contract: Subtract right counts from left counts and retain zero and negative entries in insertion order.
Counter addition drops nonpositive sums · case 01
The operation returns a result or retained state that violates this contract: Add two counters and retain only strictly positive resulting counts.
Counter addition drops nonpositive sums · case 02
The operation returns a result or retained state that violates this contract: Add two counters and retain only strictly positive resulting counts.
Counter addition drops nonpositive sums · case 03
The operation returns a result or retained state that violates this contract: Add two counters and retain only strictly positive resulting counts.
Counter addition drops nonpositive sums · case 04
The operation returns a result or retained state that violates this contract: Add two counters and retain only strictly positive resulting counts.
Counter addition drops nonpositive sums · case 05
The operation returns a result or retained state that violates this contract: Add two counters and retain only strictly positive resulting counts.
Counter update adds not replaces · case 01
The operation returns a result or retained state that violates this contract: Counter update adds supplied counts to existing counts, retaining zero and negative entries.
Counter update adds not replaces · case 02
The operation returns a result or retained state that violates this contract: Counter update adds supplied counts to existing counts, retaining zero and negative entries.
Counter update adds not replaces · case 03
The operation returns a result or retained state that violates this contract: Counter update adds supplied counts to existing counts, retaining zero and negative entries.
Counter update adds not replaces · case 04
The operation returns a result or retained state that violates this contract: Counter update adds supplied counts to existing counts, retaining zero and negative entries.
Counter update adds not replaces · case 05
The operation returns a result or retained state that violates this contract: Counter update adds supplied counts to existing counts, retaining zero and negative entries.
Counter elements skip zero negative · case 01
The operation returns a result or retained state that violates this contract: Expand positive integer counts in key insertion order; zero and negative counts produce no elements.
Counter elements skip zero negative · case 02
The operation returns a result or retained state that violates this contract: Expand positive integer counts in key insertion order; zero and negative counts produce no elements.
Counter elements skip zero negative · case 03
The operation returns a result or retained state that violates this contract: Expand positive integer counts in key insertion order; zero and negative counts produce no elements.
Counter elements skip zero negative · case 04
The operation returns a result or retained state that violates this contract: Expand positive integer counts in key insertion order; zero and negative counts produce no elements.
Counter elements skip zero negative · case 05
The operation returns a result or retained state that violates this contract: Expand positive integer counts in key insertion order; zero and negative counts produce no elements.
Counter most common stable ties · case 01
The operation returns a result or retained state that violates this contract: Return at most n [key,count] pairs by descending count, breaking ties by first insertion order.
Counter most common stable ties · case 02
The operation returns a result or retained state that violates this contract: Return at most n [key,count] pairs by descending count, breaking ties by first insertion order.
Counter most common stable ties · case 03
The operation returns a result or retained state that violates this contract: Return at most n [key,count] pairs by descending count, breaking ties by first insertion order.
Counter most common stable ties · case 04
The operation returns a result or retained state that violates this contract: Return at most n [key,count] pairs by descending count, breaking ties by first insertion order.
Counter most common stable ties · case 05
The operation returns a result or retained state that violates this contract: Return at most n [key,count] pairs by descending count, breaking ties by first insertion order.
Counter unary plus filters strictly positive · case 01
The operation returns a result or retained state that violates this contract: Unary counter normalization retains strictly positive counts without changing them.
Counter unary plus filters strictly positive · case 02
The operation returns a result or retained state that violates this contract: Unary counter normalization retains strictly positive counts without changing them.
Counter unary plus filters strictly positive · case 03
The operation returns a result or retained state that violates this contract: Unary counter normalization retains strictly positive counts without changing them.
Counter unary plus filters strictly positive · case 04
The operation returns a result or retained state that violates this contract: Unary counter normalization retains strictly positive counts without changing them.
Counter unary plus filters strictly positive · case 05
The operation returns a result or retained state that violates this contract: Unary counter normalization retains strictly positive counts without changing them.
Counter unary minus selects negative side · case 01
The operation returns a result or retained state that violates this contract: Unary minus returns positive magnitudes of negative counts only.
Counter unary minus selects negative side · case 02
The operation returns a result or retained state that violates this contract: Unary minus returns positive magnitudes of negative counts only.
Counter unary minus selects negative side · case 03
The operation returns a result or retained state that violates this contract: Unary minus returns positive magnitudes of negative counts only.
Counter unary minus selects negative side · case 04
The operation returns a result or retained state that violates this contract: Unary minus returns positive magnitudes of negative counts only.
Counter unary minus selects negative side · case 05
The operation returns a result or retained state that violates this contract: Unary minus returns positive magnitudes of negative counts only.
Counter intersection minimum positive count · case 01
The operation returns a result or retained state that violates this contract: Counter intersection takes the minimum count for shared members and drops nonpositive results.
Counter intersection minimum positive count · case 02
The operation returns a result or retained state that violates this contract: Counter intersection takes the minimum count for shared members and drops nonpositive results.
Counter intersection minimum positive count · case 03
The operation returns a result or retained state that violates this contract: Counter intersection takes the minimum count for shared members and drops nonpositive results.
Counter intersection minimum positive count · case 04
The operation returns a result or retained state that violates this contract: Counter intersection takes the minimum count for shared members and drops nonpositive results.
Counter intersection minimum positive count · case 05
The operation returns a result or retained state that violates this contract: Counter intersection takes the minimum count for shared members and drops nonpositive results.
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 ↗