FA-40780 / Heap invariants / Member archive

Interval delete retains the unremoved endpoint instead of deleting or retaining the whole pair · case 05

The bounded interval pop end certificate reports an incorrect remaining.

Member previewVariant 5 · 3 implementations · 7 checks per implementation

Case contract

A bounded interval-tail removal receives intervals, and side low or high. Remove the requested endpoint from the final interval (singleton removed wholly), returning extracted tail replacement, remaining interval list, new logical size, singleton status, surviving endpoint, and array-node count. This isolates tail extraction before global bubbling.

Why this case matters

This isolates an internal heap representation or priority-structure invariant using deterministic finite records.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression certificate 3	`{"nodes": 1, "remaining": [], "replacement": 1, "singleton": true, "size": 1, "survivor": 9}`	`{"nodes": 1, "remaining": [[9]], "replacement": 1, "singleton": true, "size": 1, "survivor": 9}`	Failed

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