{"abstract":"Unreachable predecessors erase definite assignments.","category":"Static analysis soundness","checks":6,"contract":"Predecessors are None (unreachable) or lists of definitely assigned variables. Return their reachable intersection sorted; return None when no predecessor is reachable.","evaluation_group":"model-e782957a818d113f","failed_approach":"Unioning reachable predecessors admits assignments missing on another feasible path.","family":"z-static_analysis-reachable-must-meet","id":"FA-11501","implementations":{"attempt":{"sha256":"29d9a91a18ad3f936dea5be8b6f69a2b27ed87f5005115595a2b960c9fa2aa3f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(preds):\n    live=[set(p) for p in preds if p is not None]\n    return sorted(set.union(*live)) if live else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nx='v'+str(N)\ncheck('dead predecessor ignored',solve([[x],None]),[x])\ncheck('must hold on both',solve([[x,'z'],[x]]),[x])\ncheck('reachable empty loses facts',solve([[x],[]]),[])\ncheck('all dead',solve([None,None]),None)\ncheck('no predecessors',solve([]),None)\ncheck('single reachable',solve([[x]]),[x])\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":"ded4fffc385e675beb89ad011804bcb45c955ef9311517e0259ac97c57a4a236","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(preds):\n    if not preds: return None\n    return sorted(set.intersection(*(set(p or []) for p in preds)))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nx='v'+str(N)\ncheck('dead predecessor ignored',solve([[x],None]),[x])\ncheck('must hold on both',solve([[x,'z'],[x]]),[x])\ncheck('reachable empty loses facts',solve([[x],[]]),[])\ncheck('all dead',solve([None,None]),None)\ncheck('no predecessors',solve([]),None)\ncheck('single reachable',solve([[x]]),[x])\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"},"fixed":{"sha256":"0dcd792cdf2c3918511e9a14f891607061dde34ef2cf92e45edf6258cddc33f0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(preds):\n    live=[set(p) for p in preds if p is not None]\n    return sorted(set.intersection(*live)) if live else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nx='v'+str(N)\ncheck('dead predecessor ignored',solve([[x],None]),[x])\ncheck('must hold on both',solve([[x,'z'],[x]]),[x])\ncheck('reachable empty loses facts',solve([[x],[]]),[])\ncheck('all dead',solve([None,None]),None)\ncheck('no predecessors',solve([]),None)\ncheck('single reachable',solve([[x]]),[x])\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":"z-static_analysis-reachable-must-meet","generated_at":"2026-09-29T14:38:48.525338+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic offline analysis model exposing a specific soundness or precision boundary; it does not implement a complete language analyzer.","repair":"Intersect only reachable predecessor sets; no reachable predecessor yields None.","root_cause":"The must-analysis intersects facts from unreachable predecessors.","sha256":"f43c1e3aec2e8d1f2ee55f7cae4ab2c7fe60216e9c939e28f1c6849602c9062a","title":"Unreachable predecessors erase definite assignments · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":38.036,"exit_code":1,"observations":[{"actual":["v1"],"check":"dead predecessor ignored","expected":["v1"],"passed":true},{"actual":["v1","z"],"check":"must hold on both","expected":["v1"],"passed":false},{"actual":["v1"],"check":"reachable empty loses facts","expected":[],"passed":false},{"actual":null,"check":"all dead","expected":null,"passed":true},{"actual":null,"check":"no predecessors","expected":null,"passed":true},{"actual":["v1"],"check":"single reachable","expected":["v1"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"dead predecessor ignored\", \"actual\": [\"v1\"], \"expected\": [\"v1\"], \"passed\": true}, {\"check\": \"must hold on both\", \"actual\": [\"v1\", \"z\"], \"expected\": [\"v1\"], \"passed\": false}, {\"check\": \"reachable empty loses facts\", \"actual\": [\"v1\"], \"expected\": [], \"passed\": false}, {\"check\": \"all dead\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"no predecessors\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"single reachable\", \"actual\": [\"v1\"], \"expected\": [\"v1\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.315,"exit_code":1,"observations":[{"actual":[],"check":"dead predecessor ignored","expected":["v1"],"passed":false},{"actual":["v1"],"check":"must hold on both","expected":["v1"],"passed":true},{"actual":[],"check":"reachable empty loses facts","expected":[],"passed":true},{"actual":[],"check":"all dead","expected":null,"passed":false},{"actual":null,"check":"no predecessors","expected":null,"passed":true},{"actual":["v1"],"check":"single reachable","expected":["v1"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"dead predecessor ignored\", \"actual\": [], \"expected\": [\"v1\"], \"passed\": false}, {\"check\": \"must hold on both\", \"actual\": [\"v1\"], \"expected\": [\"v1\"], \"passed\": true}, {\"check\": \"reachable empty loses facts\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"all dead\", \"actual\": [], \"expected\": null, \"passed\": false}, {\"check\": \"no predecessors\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"single reachable\", \"actual\": [\"v1\"], \"expected\": [\"v1\"], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.954,"exit_code":0,"observations":[{"actual":["v1"],"check":"dead predecessor ignored","expected":["v1"],"passed":true},{"actual":["v1"],"check":"must hold on both","expected":["v1"],"passed":true},{"actual":[],"check":"reachable empty loses facts","expected":[],"passed":true},{"actual":null,"check":"all dead","expected":null,"passed":true},{"actual":null,"check":"no predecessors","expected":null,"passed":true},{"actual":["v1"],"check":"single reachable","expected":["v1"],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"dead predecessor ignored\", \"actual\": [\"v1\"], \"expected\": [\"v1\"], \"passed\": true}, {\"check\": \"must hold on both\", \"actual\": [\"v1\"], \"expected\": [\"v1\"], \"passed\": true}, {\"check\": \"reachable empty loses facts\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"all dead\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"no predecessors\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"single reachable\", \"actual\": [\"v1\"], \"expected\": [\"v1\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}