Include disabled-adult care expenses in the VA, ID, OR, MN, and WI CDCC-conforming expense bases (credit and subtraction)

[hua7450]

Summary

Fixes the six-provision expense-base conformity gap found by the #8826 statute verification: PR #8746 added disabled-adult care (the person-level care_expenses input) to the federal IRC § 21 expense base, but five state provisions that import § 21's employment-related-expense definition still built their bases from children-only tax_unit_childcare_expenses. A household whose only qualifying individual is a disabled adult received a positive federal credit but $0 from these states.

Addresses the expense-base item in #8826. Closes #8881.

Stacked on #8855 (it includes that branch's commit because both PRs touch wi_childcare_expense_subtraction.py). Merge #8855 first; this diff then reduces to the expense-base changes only. This branch drops #8855's changelog fragment so each PR carries exactly one — no duplicate changelog entry or extra version bump regardless of merge timing.

Changes

Each state adds adult_care = add(tax_unit, period, ["care_expenses"]) to its expense base, mirroring the federal cdcc_relevant_expenses. No cap changes are needed — each state's cap already counts disabled adults:

State	Provision	§ 21 import	Cap already counts disabled adults via
VA	va_child_dependent_care_expense_deduction	Va. Code § 58.1-322.03 subd. 3 — deduction equals the amount "on which the federal credit is based under § 21"	capped_count_cdcc_eligible (federal)
ID	id_household_and_dependent_care_expense_deduction	Idaho Code § 63-3022D — expenses "as defined in section 21(b)(2)… as further specified and limited by section 21(d) and (e)"	capped_count_cdcc_eligible (federal)
OR	or_cdcc_relevant_expenses (WFHDC)	ORS 315.264(1)(a) — expenses "of a type allowable as a credit pursuant to section 21"	capped_count_cdcc_eligible (federal)
MN	mn_cdcc	Minn. Stat. § 290.067 subd. 1(a) — credit "pursuant to the provisions of section 21"	mn_cdcc_dependent_count (own incapable-of-self-care count)
WI	wi_childcare_expense_subtraction	Wis. Stat. § 71.05(6)(b)43. — adopts the § 21 expense definition	count_cdcc_eligible (federal)
WI	wi_childcare_expense_credit_potential (2024+)	Wis. Stat. § 71.07(9g)(b)2. — "using the expense limitation under par. (c) 5. rather than … 26 USC 21 (c)" swaps only the dollar cap, importing the rest of § 21	capped_count_cdcc_eligible × $10,000 per (c)5.

Statute citations were verified against primary sources during the #8826 review (see the verification comment there).

Effect

Under-inclusion only: adult-care-only households go from $0 to the statutory amount; child-only households are unchanged (care_expenses defaults to 0). Example — married couple, head earns $20k, spouse earns $6k, disabled adult dependent with $5,000 of care (MN, TY2021): expenses capped at $3,000 (one qualifying dependent) × 29% fraction at $26,000 AGI = $870, previously $0.

WI 2024+ credit (folded in from #8881)

The Act 101 branch of wi_childcare_expense_credit_potential had the same gap — its pre-2024 path includes adult care via the federal cdcc_potential, but the 2024+ standalone computation read children-only expenses. § 71.07(9g)(b)2. (verified verbatim at docs.legis.wisconsin.gov) computes "100 percent of the federal child and dependent care tax credit that the claimant may claim … using the expense limitation under par. (c) 5. rather than the expense limitation under 26 USC 21 (c)" — only the cap is swapped, so the § 21 expense definition applies. The existing $10,000 × capped-count limit already matches (c)5.'s $10,000/$20,000 amounts. New test: disabled adult dependent with $5,000 care → $1,000 credit (min(5,000, 10,000, 60,000) × 20%).

Tests

One new disabled-adult-care case per provision (VA, ID, OR, MN with hand-computed $870, WI subtraction, WI 2024+ credit). Ran locally: VA cdcc_expense, ID household_and_dependent_care, full OR WFHDC tree, full MN CDCC tree, WI subtraction + credit files + WI credits tree — 88 + 16 passed.

Out of scope (tracked in #8826)

SC § 21(e)(4) decision item; AR refundability and 2013 static-conformity flags; VT TY2022 cap and state_cdccs.yaml double-count; MD § 10-716 phase-out value check.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (f9e58e7) to head (2f968d7).
⚠️ Report is 46 commits behind head on main.

Additional details and impacted files

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##              main     #8878    +/-   ##
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  Coverage   100.00%   100.00%            
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  Files            3         9     +6     
  Lines           55       160   +105     
  Branches         0         1     +1     
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+ Hits            55       160   +105     

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unittests	100.00% <100.00%> (ø)

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