SECTION 52. Unconstitutionality of excise tax law; effect; revival of former act

If any of the provisions of this chapter imposing an excise on business corporations as defined in subsection (1) of section 30 are declared unconstitutional or inoperative by a final judgment, order or decree of the supreme court of the United States or of the supreme judicial court of the commonwealth, the portion of those provisions that was found to be unconstitutional or inoperative shall be null and void and shall become inapplicable to those corporations. In this event, the provisions of law, whether under this chapter or chapter 62, that (a) were applicable to those business corporations immediately before the enactment of the provision found to be unconstitutional or inoperative and (b) became inoperative or inapplicable in connection with the enactment of the provision found to be unconstitutional or inoperative, shall thereupon be revived and become operative and applicable in respect to those business corporations and shall be continued in full force and effect from the first day of January preceding by 6 years the first day of January of the calendar year in which the final judgment, order or decree is entered, to the same extent as if the provision found to be unconstitutional or inoperative had not been enacted. The commissioner and the local assessors shall as soon as may be assess all taxes for which liability has been incurred under the laws revived, made operative or applicable or continued in force by the foregoing provisions or any of them. The time for assessing such taxes shall be extended for a period of one year from the date of entry of such final judgment, order or decree and, for performing any duty subsequent to assessment, the time shall be extended for a further period after such assessment commensurate with the period which would have obtained under the laws hereby revived and again made operative, applicable and continued in force. Privileges and rights granted shall be correspondingly extended. Excises declared invalid by reason of the foregoing premises, which were assessed on or after the date when predecessor laws are revived, made operative or applicable or continued in force as provided in this section, shall, to the extent that those excises have been paid and are unrefunded, be credited against the taxes assessed for the same period under the laws revived and again made operative, applicable and continued in force, but if this credit exceeds the taxes due, the excess shall be refunded upon warrant of the commissioner to the state treasurer. There shall be no further or other recovery of the amounts thus credited or refunded. If any provision of this chapter other than the provisions imposing an excise shall be declared unconstitutional or inoperative, the remaining provisions shall not be affected.