FA-4423 / Mapping semantics / Member archive

Map filter keys not values · case 03

The operation returns a result or retained state that violates this contract: Keep entries whose keys occur in the supplied allowed-key list, retaining map insertion order.

Member previewVariant 3 · 3 implementations · 4 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
key differs from value	`[]`	`[["a", "b"]]`	Failed

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

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