No bill of attainder, ex post facto law, retroactive law, or law impairing the obligations of contracts shall ever be made.
BILLS OF ATTAINDER; EX POST FACTO OR RETROACTIVE LAWS; IMPAIRING OBLIGATION OF CONTRACTS
Tex. Const. art. 1, § 16, under Bill of Rights.
Tex. Const. art. 1, § 16
BILLS OF ATTAINDER; EX POST FACTO OR RETROACTIVE LAWS; IMPAIRING OBLIGATION OF CONTRACTS