Not all post-TCJA changes are in the IRC

[MaxGhenis]

Per a range of websites, TCJA removed the ALD for alimony paid, and removed alimony income as a gross income source. But this information is not in the IRC: the relevant sections are just deleted. To find this information and ensure our code accurately captures post-TCJA law, we need to consult the TCJA text itself: https://www.congress.gov/bill/115th-congress/house-bill/1/text

I've only seen this for alimony income but it could affect other parts of the law in our system. When I asked Claude for other similar ones it didn't surface any gaps in our model:

Individual Tax Rates and Brackets:
The TCJA modified tax rates and brackets, but these changes are set to expire after 2025. The IRC sections (1 and 6428) reflect the current rates, but don't include provisions for the reversion.
Standard Deduction:
The increased standard deduction is in IRC Section 63, but the sunset isn't mentioned there.
Personal Exemptions:
TCJA effectively eliminated personal exemptions by setting the amount to zero, but didn't remove IRC Section 151. The section remains, with the amount set to zero until 2025.
Child Tax Credit:
The increased credit amount and refundability are in IRC Section 24, but the reversion isn't specified there.
State and Local Tax (SALT) Deduction Cap:
The $10,000 cap is in IRC Section 164(b)(6), but doesn't mention its planned expiration.
Mortgage Interest Deduction:
The lower limits are in IRC Section 163(h)(3), without noting the scheduled reversion.
Alternative Minimum Tax (AMT):
Increased exemption amounts are in IRC Section 55, but don't specify the reversion.
Pass-through Business Income Deduction:
The Section 199A deduction is entirely new and set to expire, but the IRC doesn't mention this.
Estate Tax Exemption:
The increased exemption is in IRC Section 2010(c)(3), but doesn't note its scheduled return to previous levels.