FA-82374 / Chess move legality / Member archive

Rays run onto a ninth file and rank · case 04

A rook on a1 is offered "i1" and "a9".

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Input: {"board", "from": square of a rook, bishop or queen}. Return the sorted pseudo-legal destinations: walk each ray until the edge; an empty square is added, an enemy piece is added and ends the ray, a friendly piece ends the ray without being added.

Why this case matters

Move validators gate every move in engines, servers and arbiters; accepting an illegal move or rejecting a legal one corrupts the game record.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
bishop corner	`["e4", "f3", "g2", "i2"]`	`["e4", "f3", "g2"]`	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.