On the opening page, page 5, of his book, الناسخ والمنسوخ في القرآن الكريم, Dr. Husayn Nassaar, summarizes "the importance of knowing about abrogation" by quoting three narrations without bothering to authenticate any of them.
Is it scholarly to cite for evidence something that someone may or may not have said?
His first narration is from Huzhayfa ibn Hasl Al-Yamaani saying, "Only one of three may give a ruling: One who knows the abrogating and the abrogated in the Quran, a leader who must, or a fool."
I tried to look for that narration but could not find it. And even if it is authentic, it is the opinion of Huzhayfa unless it can be proven that it traces back to the Prophet (PBUH).
The second narration Dr. Nassaar cites is the هلكت وأهلكت story
attributed to Ali ibn Abi-Taalib, may God have been pleased with him. We've discussed this before many times.
The last narration is attributed to Ibn Abbaas, may God have been pleased with him, in which he interprets 2:269 to mean the knowledge, among other things, of abrogation in the Quran!
Again, I tried to find that narration and couldn't. And again, even if were authentic, it expresses an interpretation of one man who was not inspired by God.
So the "evidence" Dr. Nassaar opens his book with is either unknown or authentically weak. Is that any way to start a book? But, to be fair to him, he does not agree or disagree with the notion. In fact, he makes no conclusion one way or another as he finishes the book.