Sec. 21.016.  BONDS INCONTESTABLE, VALID, AND BINDING.  (a)  After approval by the attorney general, registration by the comptroller, and delivery to the purchaser, the bonds are incontestable and constitute general obligations of the state.
(b)  After approval by the attorney general and registration by the comptroller, the bonds shall be held to be valid and binding obligations of the state in any action, suit, or other proceeding in which their validity is questioned.
Acts 1975, 64th Leg., p. 1405, ch. 545, Sec. 1, eff. Sept. 1, 1975.