(4)[Amended Nov. 1982] The terms of office of justices of the supreme court serving on August 1, 1978, shall expire on the July 31 next preceding the first Monday in January on which such terms would otherwise have expired, but such advancement of the date of term expiration shall not impair any retirement rights vested in any such justice if the term had expired on the first Monday in January. [1975 J.R. 13, 1977 J.R. 7, vote April 1977; 1979 J.R. 36, 1981 J.R. 29, vote Nov. 1982]