FA-4507 / Listener lifecycle / Member archive

Listener registration replaces identity · case 02

The operation returns a result or retained state that violates this contract: Listeners have identity, event name, once flag, and registration order. Dispatch uses a snapshot; listener actions remove another listener or add a new one. Return callback identities in invocation order. Registering an existing identity replaces its event metadata while preserving its registration position.

Member previewVariant 2 · 3 implementations · 5 checks per implementation

Case scope

A controlled failure with recorded boundary checks.

Why this case matters

A controlled local-runtime regression for collection APIs, language semantics, or ownership wrappers. Fixtures include boundary and interaction cases.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
replacement changes event but preserves order	`["b", ["a", "b"]]`	`["a", "b", ["a", "b"]]`	Failed

MEMBER ARCHIVE

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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