Has anyone, based on great performance, ever been awarded a higher degree than the one they enrolled for? Out of curiosity, I was wondering if anyone, historically, has ever been awarded a degree that was a level higher than the one they were enrolled in and studying for, simply because their performance warranted a higher award? For example, somebody could have been awarded a MPhil instead of an MSc or a PhD instead of an MSc?
Although a bit old, there's the case of Luzin's Master's thesis: . . . he completed his thesis The integral and trigonometric series which he submitted in 1915. After his oral examination he was awarded a doctorate, despite having submitted his thesis for the Master's Degree. In fact, even for a Ph.D. thesis, Luzin's is one of the strongest ever written in mathematics --- in my opinion easily in the top 20 (and probably in the top 10) of all-time Ph.D. theses in mathematics for its influence on later developments.

This appears to be the published version of Luzin's thesis, which is 242 pages and in Russian, with the table of contents on pp. 241-242. For references to it, this search and this other search seem to work the best. I didn't get many hits for the title's French translation, by the way.