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FA-44281 / Borrow checking / Open access

An incomplete positive fixed-point borrow result is reused as final · case 01

An incomplete positive fixed-point borrow result is reused as final.

Verified by executionVariant 1 · 21 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The static analyzer mishandles provisional result: an incomplete positive fixed-point borrow result is reused as final.

VERIFIED REPAIR

Apply the specified transfer or inference rule at this site: if d['reused'] and not d['complete']: errors.append('provisional-result').

Unsuccessful approach: The partial repair uses if d['reused'] and not d['complete'] and d['negative']: errors.append('provisional-result'), which still violates the stipulated analysis contract.

Case contract

Validate reuse of static borrow proof certificates. Cache entry belongs to same IR revision, same normalized place, same mutability, same lifetime substitution, same solver universe, same CFG edge kind and same target layout; negative results are invalidated when new outlives facts arrive; incomplete fixed-point results are never reusable; diagnostic reuse rebinds source spans to current lifetime occurrence mapping. Input is a fully explicit descriptor of the stated toy IR. Return rule identifiers in declaration order; absent optional obligations use the provided neutral defaults. No rule is an assertion about a production language.

Why this case matters

A finite offline static-analysis model of ownership and borrowing; it does not execute the analyzed program.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(d):
    errors=[]
    if d['reused'] and d['cached_revision']!=d['revision']: errors.append('ir-revision')
    if d['reused'] and d['cached_place']!=d['place']: errors.append('normalized-place-key')
    if d['reused'] and d['cached_mut']!=d['mutable']: errors.append('permission-key')
    if d['reused'] and d['cached_substitution']!=d['substitution']: errors.append('substitution-key')
    if d['reused'] and d['cached_universe']!=d['universe']: errors.append('universe-key')
    if d['reused'] and d['cached_edge']!=d['edge']: errors.append('edge-kind-key')
    if d['reused'] and d['cached_layout']!=d['layout']: errors.append('layout-key')
    if d['reused'] and d['negative'] and set(d['old_facts'])!=set(d['facts']): errors.append('negative-fact-invalidation')
    if False: errors.append('provisional-result')
    if d['reused'] and d['cached_spans']!=d['spans']: errors.append('diagnostic-span-rebind')
    return errors
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
base={'cached_revision': 0, 'revision': 0, 'cached_place': [], 'place': [], 'cached_mut': False, 'mutable': False, 'cached_substitution': {}, 'substitution': {}, 'cached_universe': 0, 'universe': 0, 'cached_edge': 'normal', 'edge': 'normal', 'cached_layout': [], 'layout': [], 'negative': False, 'old_facts': [], 'facts': [], 'complete': True, 'reused': False, 'cached_spans': {}, 'spans': {}}
check('well formed empty obligations',solve(base),[])
check('ir-revision regression 0', solve(dict(base, **({'reused':True,'cached_revision':N,'revision':N+1}))), ['ir-revision'])
check('ir-revision regression 1', solve(dict(base, **({'reused':True,'cached_revision':N+1,'revision':N+2}))), ['ir-revision'])
check('normalized-place-key regression 0', solve(dict(base, **({'reused':True,'cached_place':['r','a'],'place':['r','b']}))), ['normalized-place-key'])
check('normalized-place-key regression 1', solve(dict(base, **({'reused':True,'cached_place':['r',N],'place':['r',N+1]}))), ['normalized-place-key'])
check('permission-key regression 0', solve(dict(base, **({'reused':True,'cached_mut':False,'mutable':True}))), ['permission-key'])
check('permission-key regression 1', solve(dict(base, **({'reused':True,'cached_mut':False,'mutable':True,'revision':N,'cached_revision':N}))), ['permission-key'])
check('substitution-key regression 0', solve(dict(base, **({'reused':True,'cached_substitution':{'a':'x'},'substitution':{'a':'y'}}))), ['substitution-key'])
check('substitution-key regression 1', solve(dict(base, **({'reused':True,'cached_substitution':{'a':N},'substitution':{'a':N+1}}))), ['substitution-key'])
check('universe-key regression 0', solve(dict(base, **({'reused':True,'cached_universe':N,'universe':N+1}))), ['universe-key'])
check('universe-key regression 1', solve(dict(base, **({'reused':True,'cached_universe':N+1,'universe':N+2}))), ['universe-key'])
check('edge-kind-key regression 0', solve(dict(base, **({'reused':True,'cached_edge':'normal','edge':'unwind'}))), ['edge-kind-key'])
check('edge-kind-key regression 1', solve(dict(base, **({'reused':True,'cached_edge':'normal','edge':'cancel','revision':N,'cached_revision':N}))), ['edge-kind-key'])
check('layout-key regression 0', solve(dict(base, **({'reused':True,'cached_layout':[0,4],'layout':[0,8]}))), ['layout-key'])
check('layout-key regression 1', solve(dict(base, **({'reused':True,'cached_layout':[0,N],'layout':[0,N+1]}))), ['layout-key'])
check('negative-fact-invalidation regression 0', solve(dict(base, **({'reused':True,'negative':True,'old_facts':['a'],'facts':['a','b']}))), ['negative-fact-invalidation'])
check('negative-fact-invalidation regression 1', solve(dict(base, **({'reused':True,'negative':True,'old_facts':[N],'facts':[N,N+1]}))), ['negative-fact-invalidation'])
check('provisional-result regression 0', solve(dict(base, **({'reused':True,'complete':False}))), ['provisional-result'])
check('provisional-result regression 1', solve(dict(base, **({'reused':True,'complete':False,'revision':N,'cached_revision':N}))), ['provisional-result'])
check('diagnostic-span-rebind regression 0', solve(dict(base, **({'reused':True,'cached_spans':{'a':1},'spans':{'a':2}}))), ['diagnostic-span-rebind'])
check('diagnostic-span-rebind regression 1', solve(dict(base, **({'reused':True,'cached_spans':{'a':N},'spans':{'a':N+1}}))), ['diagnostic-span-rebind'])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
well formed empty obligations[][]Passed
ir-revision regression 0['ir-revision']['ir-revision']Passed
ir-revision regression 1['ir-revision']['ir-revision']Passed
normalized-place-key regression 0['normalized-place-key']['normalized-place-key']Passed
normalized-place-key regression 1['normalized-place-key']['normalized-place-key']Passed
permission-key regression 0['permission-key']['permission-key']Passed
permission-key regression 1['permission-key']['permission-key']Passed
substitution-key regression 0['substitution-key']['substitution-key']Passed
substitution-key regression 1['substitution-key']['substitution-key']Passed
universe-key regression 0['universe-key']['universe-key']Passed
universe-key regression 1['universe-key']['universe-key']Passed
edge-kind-key regression 0['edge-kind-key']['edge-kind-key']Passed
edge-kind-key regression 1['edge-kind-key']['edge-kind-key']Passed
layout-key regression 0['layout-key']['layout-key']Passed
layout-key regression 1['layout-key']['layout-key']Passed
negative-fact-invalidation regression 0['negative-fact-invalidation']['negative-fact-invalidation']Passed
negative-fact-invalidation regression 1['negative-fact-invalidation']['negative-fact-invalidation']Passed
provisional-result regression 0[]['provisional-result']Failed
provisional-result regression 1[]['provisional-result']Failed
diagnostic-span-rebind regression 0['diagnostic-span-rebind']['diagnostic-span-rebind']Passed
diagnostic-span-rebind regression 1['diagnostic-span-rebind']['diagnostic-span-rebind']Passed

SHA-256 / 47799ca7b7ae16e844e02be233de4a301da847eae429948f2acdb63073bc051d

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(d):
    errors=[]
    if d['reused'] and d['cached_revision']!=d['revision']: errors.append('ir-revision')
    if d['reused'] and d['cached_place']!=d['place']: errors.append('normalized-place-key')
    if d['reused'] and d['cached_mut']!=d['mutable']: errors.append('permission-key')
    if d['reused'] and d['cached_substitution']!=d['substitution']: errors.append('substitution-key')
    if d['reused'] and d['cached_universe']!=d['universe']: errors.append('universe-key')
    if d['reused'] and d['cached_edge']!=d['edge']: errors.append('edge-kind-key')
    if d['reused'] and d['cached_layout']!=d['layout']: errors.append('layout-key')
    if d['reused'] and d['negative'] and set(d['old_facts'])!=set(d['facts']): errors.append('negative-fact-invalidation')
    if d['reused'] and not d['complete'] and d['negative']: errors.append('provisional-result')
    if d['reused'] and d['cached_spans']!=d['spans']: errors.append('diagnostic-span-rebind')
    return errors
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
base={'cached_revision': 0, 'revision': 0, 'cached_place': [], 'place': [], 'cached_mut': False, 'mutable': False, 'cached_substitution': {}, 'substitution': {}, 'cached_universe': 0, 'universe': 0, 'cached_edge': 'normal', 'edge': 'normal', 'cached_layout': [], 'layout': [], 'negative': False, 'old_facts': [], 'facts': [], 'complete': True, 'reused': False, 'cached_spans': {}, 'spans': {}}
check('well formed empty obligations',solve(base),[])
check('ir-revision regression 0', solve(dict(base, **({'reused':True,'cached_revision':N,'revision':N+1}))), ['ir-revision'])
check('ir-revision regression 1', solve(dict(base, **({'reused':True,'cached_revision':N+1,'revision':N+2}))), ['ir-revision'])
check('normalized-place-key regression 0', solve(dict(base, **({'reused':True,'cached_place':['r','a'],'place':['r','b']}))), ['normalized-place-key'])
check('normalized-place-key regression 1', solve(dict(base, **({'reused':True,'cached_place':['r',N],'place':['r',N+1]}))), ['normalized-place-key'])
check('permission-key regression 0', solve(dict(base, **({'reused':True,'cached_mut':False,'mutable':True}))), ['permission-key'])
check('permission-key regression 1', solve(dict(base, **({'reused':True,'cached_mut':False,'mutable':True,'revision':N,'cached_revision':N}))), ['permission-key'])
check('substitution-key regression 0', solve(dict(base, **({'reused':True,'cached_substitution':{'a':'x'},'substitution':{'a':'y'}}))), ['substitution-key'])
check('substitution-key regression 1', solve(dict(base, **({'reused':True,'cached_substitution':{'a':N},'substitution':{'a':N+1}}))), ['substitution-key'])
check('universe-key regression 0', solve(dict(base, **({'reused':True,'cached_universe':N,'universe':N+1}))), ['universe-key'])
check('universe-key regression 1', solve(dict(base, **({'reused':True,'cached_universe':N+1,'universe':N+2}))), ['universe-key'])
check('edge-kind-key regression 0', solve(dict(base, **({'reused':True,'cached_edge':'normal','edge':'unwind'}))), ['edge-kind-key'])
check('edge-kind-key regression 1', solve(dict(base, **({'reused':True,'cached_edge':'normal','edge':'cancel','revision':N,'cached_revision':N}))), ['edge-kind-key'])
check('layout-key regression 0', solve(dict(base, **({'reused':True,'cached_layout':[0,4],'layout':[0,8]}))), ['layout-key'])
check('layout-key regression 1', solve(dict(base, **({'reused':True,'cached_layout':[0,N],'layout':[0,N+1]}))), ['layout-key'])
check('negative-fact-invalidation regression 0', solve(dict(base, **({'reused':True,'negative':True,'old_facts':['a'],'facts':['a','b']}))), ['negative-fact-invalidation'])
check('negative-fact-invalidation regression 1', solve(dict(base, **({'reused':True,'negative':True,'old_facts':[N],'facts':[N,N+1]}))), ['negative-fact-invalidation'])
check('provisional-result regression 0', solve(dict(base, **({'reused':True,'complete':False}))), ['provisional-result'])
check('provisional-result regression 1', solve(dict(base, **({'reused':True,'complete':False,'revision':N,'cached_revision':N}))), ['provisional-result'])
check('diagnostic-span-rebind regression 0', solve(dict(base, **({'reused':True,'cached_spans':{'a':1},'spans':{'a':2}}))), ['diagnostic-span-rebind'])
check('diagnostic-span-rebind regression 1', solve(dict(base, **({'reused':True,'cached_spans':{'a':N},'spans':{'a':N+1}}))), ['diagnostic-span-rebind'])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
well formed empty obligations[][]Passed
ir-revision regression 0['ir-revision']['ir-revision']Passed
ir-revision regression 1['ir-revision']['ir-revision']Passed
normalized-place-key regression 0['normalized-place-key']['normalized-place-key']Passed
normalized-place-key regression 1['normalized-place-key']['normalized-place-key']Passed
permission-key regression 0['permission-key']['permission-key']Passed
permission-key regression 1['permission-key']['permission-key']Passed
substitution-key regression 0['substitution-key']['substitution-key']Passed
substitution-key regression 1['substitution-key']['substitution-key']Passed
universe-key regression 0['universe-key']['universe-key']Passed
universe-key regression 1['universe-key']['universe-key']Passed
edge-kind-key regression 0['edge-kind-key']['edge-kind-key']Passed
edge-kind-key regression 1['edge-kind-key']['edge-kind-key']Passed
layout-key regression 0['layout-key']['layout-key']Passed
layout-key regression 1['layout-key']['layout-key']Passed
negative-fact-invalidation regression 0['negative-fact-invalidation']['negative-fact-invalidation']Passed
negative-fact-invalidation regression 1['negative-fact-invalidation']['negative-fact-invalidation']Passed
provisional-result regression 0[]['provisional-result']Failed
provisional-result regression 1[]['provisional-result']Failed
diagnostic-span-rebind regression 0['diagnostic-span-rebind']['diagnostic-span-rebind']Passed
diagnostic-span-rebind regression 1['diagnostic-span-rebind']['diagnostic-span-rebind']Passed

SHA-256 / 5db06f8e159b9d045fbd47871fc845fa8f52363842237feaf5b7662484b5ff43

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(d):
    errors=[]
    if d['reused'] and d['cached_revision']!=d['revision']: errors.append('ir-revision')
    if d['reused'] and d['cached_place']!=d['place']: errors.append('normalized-place-key')
    if d['reused'] and d['cached_mut']!=d['mutable']: errors.append('permission-key')
    if d['reused'] and d['cached_substitution']!=d['substitution']: errors.append('substitution-key')
    if d['reused'] and d['cached_universe']!=d['universe']: errors.append('universe-key')
    if d['reused'] and d['cached_edge']!=d['edge']: errors.append('edge-kind-key')
    if d['reused'] and d['cached_layout']!=d['layout']: errors.append('layout-key')
    if d['reused'] and d['negative'] and set(d['old_facts'])!=set(d['facts']): errors.append('negative-fact-invalidation')
    if d['reused'] and not d['complete']: errors.append('provisional-result')
    if d['reused'] and d['cached_spans']!=d['spans']: errors.append('diagnostic-span-rebind')
    return errors
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
base={'cached_revision': 0, 'revision': 0, 'cached_place': [], 'place': [], 'cached_mut': False, 'mutable': False, 'cached_substitution': {}, 'substitution': {}, 'cached_universe': 0, 'universe': 0, 'cached_edge': 'normal', 'edge': 'normal', 'cached_layout': [], 'layout': [], 'negative': False, 'old_facts': [], 'facts': [], 'complete': True, 'reused': False, 'cached_spans': {}, 'spans': {}}
check('well formed empty obligations',solve(base),[])
check('ir-revision regression 0', solve(dict(base, **({'reused':True,'cached_revision':N,'revision':N+1}))), ['ir-revision'])
check('ir-revision regression 1', solve(dict(base, **({'reused':True,'cached_revision':N+1,'revision':N+2}))), ['ir-revision'])
check('normalized-place-key regression 0', solve(dict(base, **({'reused':True,'cached_place':['r','a'],'place':['r','b']}))), ['normalized-place-key'])
check('normalized-place-key regression 1', solve(dict(base, **({'reused':True,'cached_place':['r',N],'place':['r',N+1]}))), ['normalized-place-key'])
check('permission-key regression 0', solve(dict(base, **({'reused':True,'cached_mut':False,'mutable':True}))), ['permission-key'])
check('permission-key regression 1', solve(dict(base, **({'reused':True,'cached_mut':False,'mutable':True,'revision':N,'cached_revision':N}))), ['permission-key'])
check('substitution-key regression 0', solve(dict(base, **({'reused':True,'cached_substitution':{'a':'x'},'substitution':{'a':'y'}}))), ['substitution-key'])
check('substitution-key regression 1', solve(dict(base, **({'reused':True,'cached_substitution':{'a':N},'substitution':{'a':N+1}}))), ['substitution-key'])
check('universe-key regression 0', solve(dict(base, **({'reused':True,'cached_universe':N,'universe':N+1}))), ['universe-key'])
check('universe-key regression 1', solve(dict(base, **({'reused':True,'cached_universe':N+1,'universe':N+2}))), ['universe-key'])
check('edge-kind-key regression 0', solve(dict(base, **({'reused':True,'cached_edge':'normal','edge':'unwind'}))), ['edge-kind-key'])
check('edge-kind-key regression 1', solve(dict(base, **({'reused':True,'cached_edge':'normal','edge':'cancel','revision':N,'cached_revision':N}))), ['edge-kind-key'])
check('layout-key regression 0', solve(dict(base, **({'reused':True,'cached_layout':[0,4],'layout':[0,8]}))), ['layout-key'])
check('layout-key regression 1', solve(dict(base, **({'reused':True,'cached_layout':[0,N],'layout':[0,N+1]}))), ['layout-key'])
check('negative-fact-invalidation regression 0', solve(dict(base, **({'reused':True,'negative':True,'old_facts':['a'],'facts':['a','b']}))), ['negative-fact-invalidation'])
check('negative-fact-invalidation regression 1', solve(dict(base, **({'reused':True,'negative':True,'old_facts':[N],'facts':[N,N+1]}))), ['negative-fact-invalidation'])
check('provisional-result regression 0', solve(dict(base, **({'reused':True,'complete':False}))), ['provisional-result'])
check('provisional-result regression 1', solve(dict(base, **({'reused':True,'complete':False,'revision':N,'cached_revision':N}))), ['provisional-result'])
check('diagnostic-span-rebind regression 0', solve(dict(base, **({'reused':True,'cached_spans':{'a':1},'spans':{'a':2}}))), ['diagnostic-span-rebind'])
check('diagnostic-span-rebind regression 1', solve(dict(base, **({'reused':True,'cached_spans':{'a':N},'spans':{'a':N+1}}))), ['diagnostic-span-rebind'])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
well formed empty obligations[][]Passed
ir-revision regression 0['ir-revision']['ir-revision']Passed
ir-revision regression 1['ir-revision']['ir-revision']Passed
normalized-place-key regression 0['normalized-place-key']['normalized-place-key']Passed
normalized-place-key regression 1['normalized-place-key']['normalized-place-key']Passed
permission-key regression 0['permission-key']['permission-key']Passed
permission-key regression 1['permission-key']['permission-key']Passed
substitution-key regression 0['substitution-key']['substitution-key']Passed
substitution-key regression 1['substitution-key']['substitution-key']Passed
universe-key regression 0['universe-key']['universe-key']Passed
universe-key regression 1['universe-key']['universe-key']Passed
edge-kind-key regression 0['edge-kind-key']['edge-kind-key']Passed
edge-kind-key regression 1['edge-kind-key']['edge-kind-key']Passed
layout-key regression 0['layout-key']['layout-key']Passed
layout-key regression 1['layout-key']['layout-key']Passed
negative-fact-invalidation regression 0['negative-fact-invalidation']['negative-fact-invalidation']Passed
negative-fact-invalidation regression 1['negative-fact-invalidation']['negative-fact-invalidation']Passed
provisional-result regression 0['provisional-result']['provisional-result']Passed
provisional-result regression 1['provisional-result']['provisional-result']Passed
diagnostic-span-rebind regression 0['diagnostic-span-rebind']['diagnostic-span-rebind']Passed
diagnostic-span-rebind regression 1['diagnostic-span-rebind']['diagnostic-span-rebind']Passed

SHA-256 / e07a91d2c5d03114027bfb411d6f4a36c5eb2d58c1b59201804912fc1a0bfb29

Verification & scope

The explicitly stated toy language is the complete scope; this is not a production compiler or a claim about Rust semantics. 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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:44:10.726828+00:00.

Case digest / 03a7d42d104b14e5a5974edea85f3ad1bca9b3175811fc3d200484ceff451bec