{"abstract":"The operation returns a result or retained state that violates this contract: Return the full-list occurrence count corresponding to each original element.","category":"Sequence semantics","checks":4,"contract":"Return the full-list occurrence count corresponding to each original element. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","contract_signature":"x, y=None","evaluation_group":"model-eac0c291d84630f6","failed_approach":"Deduplicating the output domain loses its position-to-count correspondence.","family":"xr-occurrence-count-per-position","id":"FA-4221","implementations":{"attempt":{"sha256":"a11d9eb48ff2e5bfa2c7ca78420d1d4b7cbb99792438a84613bbb9bd12b98959","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return [x.count(v) for v in dict.fromkeys(x)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('empty collection', solve([]), [])\ncheck('singleton collection', solve(['a']), [1])\ncheck('two distinct elements', solve(['a', 'b']), [1, 1])\ncheck('nonadjacent duplicate and unsorted order', solve(['b', 'a', 'b', 'c']), [2, 1, 2, 1])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"a669845937aebcbc68e210e9e892af8a0013d690fe9938fc0a068ec130fb04cd","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    return [x[:i+1].count(v) for i,v in enumerate(x)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('empty collection', solve([]), [])\ncheck('singleton collection', solve(['a']), [1])\ncheck('two distinct elements', solve(['a', 'b']), [1, 1])\ncheck('nonadjacent duplicate and unsorted order', solve(['b', 'a', 'b', 'c']), [2, 1, 2, 1])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xr-occurrence-count-per-position","generated_at":"2026-09-29T14:37:37.061706+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A controlled local-runtime regression for collection APIs, language semantics, or ownership wrappers. Fixtures include boundary and interaction cases.","root_cause":"Prefix counts omit equal occurrences later in the sequence.","sha256":"fada5e7c3b0ca5f29dccc824de0c4dc8153208e217d7a6fcf52be97d54360a92","title":"Occurrence count per position · case 01","variant":1,"variant_policy":"Five execution reruns of a fixed adversarial fixture suite; variant number does not alter semantic inputs.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":38.752,"exit_code":1,"observations":[{"actual":[],"check":"empty collection","expected":[],"passed":true},{"actual":[1],"check":"singleton collection","expected":[1],"passed":true},{"actual":[1,1],"check":"two distinct elements","expected":[1,1],"passed":true},{"actual":[2,1,1],"check":"nonadjacent duplicate and unsorted order","expected":[2,1,2,1],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"empty collection\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"singleton collection\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"two distinct elements\", \"actual\": [1, 1], \"expected\": [1, 1], \"passed\": true}, {\"check\": \"nonadjacent duplicate and unsorted order\", \"actual\": [2, 1, 1], \"expected\": [2, 1, 2, 1], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":35.906,"exit_code":1,"observations":[{"actual":[],"check":"empty collection","expected":[],"passed":true},{"actual":[1],"check":"singleton collection","expected":[1],"passed":true},{"actual":[1,1],"check":"two distinct elements","expected":[1,1],"passed":true},{"actual":[1,1,2,1],"check":"nonadjacent duplicate and unsorted order","expected":[2,1,2,1],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"empty collection\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"singleton collection\", \"actual\": [1], \"expected\": [1], \"passed\": true}, {\"check\": \"two distinct elements\", \"actual\": [1, 1], \"expected\": [1, 1], \"passed\": true}, {\"check\": \"nonadjacent duplicate and unsorted order\", \"actual\": [1, 1, 2, 1], \"expected\": [2, 1, 2, 1], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}