MN CTC eligible child check missing dependent requirement

[PavelMakarchuk]

Bug

mn_child_and_working_families_credits_ctc_eligible_child does not check is_tax_unit_dependent, allowing a tax unit head to count as their own qualifying child for the MN Child Tax Credit.

Reproduction

A 16-year-old single filer in MN with no income and no dependents receives a $1,750 MN CTC. The correct result is $0.

- period: 2024
  input:
    people:
      person1:
        age: 16
        employment_income: 0
        is_tax_unit_head: true
    tax_units:
      tax_unit:
        members: [person1]
    households:
      household:
        members: [person1]
        state_fips: 27
  output:
    mn_income_tax: 0  # PE currently gives -1750

Root Cause

In policyengine_us/variables/gov/states/mn/tax/income/credits/mn_child_and_working_families_credits_ctc_eligible_child.py, the formula only checks:

1. age < 18 → True (age 16)
2. meets_eitc_identification_requirements → True (has SSN)

It does not check whether the person is a dependent. The 16-year-old filer passes both checks and is counted as their own qualifying child, generating a $1,750 CTC.

Legal Basis

MN §290.0661 defines "qualifying child" per IRC §32(c), which references §152(c). Under §152(c)(2), a qualifying child must bear a relationship to the taxpayer (son, daughter, stepchild, foster child, sibling, or descendant thereof). A person cannot be their own qualifying child.

• MN §290.0661
• IRC §32(c)

Suggested Fix

Add is_tax_unit_dependent check to the eligible child formula:

return age_eligible & meets_eitc_identification_requirements & person("is_tax_unit_dependent", period)

Related

• policyengine-taxsim#688