FA-90742 / Garbage collector invariants / Member archive

Remembered sets: target card recorded instead of the slot card · case 02

Evacuation rescans cards in the target region, which do not contain the referencing slot.

Member previewVariant 2 · 3 implementations · 6 checks per implementation

Case contract

Region-based remembered sets. kinds[r] is young, old, humongous or hcont (a continuation region of the humongous object that starts in the nearest preceding humongous region). For each write [slot, value]: null values are ignored; the target region is the region of value, mapped from continuations back to the humongous start; writes within one region and writes whose slot is in a young region are filtered; otherwise the slot's card index (slot // card) is added to the target region's set. Return the remembered sets.

Why this case matters

Remembered-set filtering decides which cross-region pointers an evacuation will find.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: old-to-young and old-to-old writes	`{"1": [8], "6": [48], "7": [56]}`	`{"1": [0], "6": [16], "7": [50]}`	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.