Indiana Code Title 6. Taxation § 6-9-10-10

Sec. 10.  With respect to:

the general assembly covenants with the county, the purchasers or owners of the bonds or other obligations described in subdivision (1), and the owners of bonds described in subdivision (2) that this chapter will not be repealed or amended in any manner that will adversely affect the imposition or collection of the tax imposed under this chapter if the principal of any bonds, the interest on any bonds, or the lease rentals due under any lease remain unpaid.