FA-62473 / Tax bracket computation / Member archive

Nonrefundable credits are allowed to produce a refund · case 03

A nonrefundable credit larger than the tax pays out cash.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

solve(tax, credits): tax is integer cents >= 0; credits is a list of [kind, cents] with kind 'nonref' (nonrefundable, unused part lost), 'carry' (nonrefundable, unused part carried forward) or 'ref' (refundable). Unknown kinds return 'ERR:kind'. Apply all nonref credits first (limited to the remaining tax), then carry credits (limited to what remains), then refundable credits in full (a negative result is a refund). Return [final_tax, carryforward].

Why this case matters

Tax computations hinge on which slice, threshold, ordering and rounding rule applies at each step; a misplaced boundary silently misstates liabilities.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression nonref-limit 1	`[0, 150]`	`[0, 0]`	Failed

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