FA-11476 / Compiler transformation correctness / Open access

Boolean simplification erases evaluation of an effectful left operand · case 01

Boolean simplification erases evaluation of an effectful left operand.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The identity lhs AND false is folded without preserving lhs evaluation.

VERIFIED REPAIR

Fold the value while retaining the left effect trace if present.

Unsuccessful approach: Retaining only writes loses observable reads.

Case contract

Model lowering lhs AND false as [False, trace]; lhs is always evaluated and contributes its effect unless pure. Effect is pure, write or read; label identifies the operation.

Why this case matters

A deterministic miniature compiler-pass model; inputs are explicit IR facts, not a production compiler.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(effect, label):
    return [False, []]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('pure', solve('pure',N), [False,[]])
check('write', solve('write',N), [False,[N]])
check('read', solve('read',N), [False,[N]])
check('zero label read', solve('read',0), [False,[0]])
check('empty label write', solve('write',''), [False,['']])
check('other pure label', solve('pure',N+1), [False,[]])
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 fixture	Actual	Expected	Outcome
pure	`[False, []]`	`[False, []]`	Passed
write	`[False, []]`	`[False, [1]]`	Failed
read	`[False, []]`	`[False, [1]]`	Failed
zero label read	`[False, []]`	`[False, [0]]`	Failed
empty label write	`[False, []]`	`[False, ['']]`	Failed
other pure label	`[False, []]`	`[False, []]`	Passed

SHA-256 / a53bbfb67fc07f9b68ea0948285d5e1901b3a34991e000352449dc70ad26dd34

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(effect, label):
    return [False, [label] if effect == 'write' else []]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('pure', solve('pure',N), [False,[]])
check('write', solve('write',N), [False,[N]])
check('read', solve('read',N), [False,[N]])
check('zero label read', solve('read',0), [False,[0]])
check('empty label write', solve('write',''), [False,['']])
check('other pure label', solve('pure',N+1), [False,[]])
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 fixture	Actual	Expected	Outcome
pure	`[False, []]`	`[False, []]`	Passed
write	`[False, [1]]`	`[False, [1]]`	Passed
read	`[False, []]`	`[False, [1]]`	Failed
zero label read	`[False, []]`	`[False, [0]]`	Failed
empty label write	`[False, ['']]`	`[False, ['']]`	Passed
other pure label	`[False, []]`	`[False, []]`	Passed

SHA-256 / 7614dce1981298ed8b229eead7012e5b2485528691a2a3ea83d365c12d89b4b7

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(effect, label):
    return [False, [] if effect == 'pure' else [label]]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('pure', solve('pure',N), [False,[]])
check('write', solve('write',N), [False,[N]])
check('read', solve('read',N), [False,[N]])
check('zero label read', solve('read',0), [False,[0]])
check('empty label write', solve('write',''), [False,['']])
check('other pure label', solve('pure',N+1), [False,[]])
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 fixture	Actual	Expected	Outcome
pure	`[False, []]`	`[False, []]`	Passed
write	`[False, [1]]`	`[False, [1]]`	Passed
read	`[False, [1]]`	`[False, [1]]`	Passed
zero label read	`[False, [0]]`	`[False, [0]]`	Passed
empty label write	`[False, ['']]`	`[False, ['']]`	Passed
other pure label	`[False, []]`	`[False, []]`	Passed

SHA-256 / f5601d4799276b3a4371385142ae549d6e8e3b0586c4985bfcbd361ce7ac7e9f

Verification & scope

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 2026-09-29T14:38:48.280959+00:00.

Case digest / 79593d330e9663c90d941f6c0046d9a003e2e2cc1c2e86a7318abfce6367ba79