FA-4197 / Sequence semantics / Member archive

Reverse enumeration retains indices · case 02

The operation returns a result or retained state that violates this contract: Visit elements in reverse order while retaining their original indices.

Member previewVariant 2 · 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
two distinct elements	`[[0, "b"], [1, "a"]]`	`[[1, "b"], [0, "a"]]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

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

Member access is invitation-based. Sign in with your invited account to inspect the sources.