Well,m with the plethora of Catholic claims of "special revelation" some might claim to fit thru a loophole.
No one, moreover, so long as he is in this mortal life, ought so far to presume as regards the secret mystery of divine predestination, as to determine for certain that he is assuredly in [Page 40] the number of the predestinate; as if it were true, that he that is justified, either cannot sin any more, or, if he do sin, that he ought to promise himself an assured repentance; for except by special revelation, it cannot be known whom God hath chosen unto Himself. [Trent, The Sixth Session, CHAPTER XII, http://history.hanover.edu/early/trent/ct06.html]
. No one can be absolutely certain of his or her salvation unless--as to Magdalen, to the man with the palsy, or to the penitent thief--a special revelation be given (Trent, Sess. VI, can. xvi). http://www.newadvent.org/cathen/06701a.htm
However, although the "no true Scotsman" reasoning seem to apply to the final perseverance OSAS. one can know that they no have eternal life, and can attain to a condition in which they will never fall as they walk therein.
These things [4+ chapters] have I written unto you that believe on the name of the Son of God; that ye may know that ye have eternal life, and that ye may believe on the name of the Son of God. (1 John 5:13)
Wherefore the rather, brethren, give diligence to make your calling and election sure: for if ye do these things, ye shall never fall: For so an entrance shall be ministered unto you abundantly into the everlasting kingdom of our Lord and Saviour Jesus Christ. (2 Peter 1:10-11)
Such a revelation may be a good warning or a good consolation, and may conduce to renewed fervor in the faith. But it is not a source of dogma.