Ya know, from the way River talked about The Doctor's ability to regenerate in "The Impossible Astronaut", and her knowledge about the process in general, it would certainly seem to indicate that she's had some actual experience with at least one of The Doctor's regenerations, if not more than one. So where does this expertise come from, when we've pretty much witnessed all of the doc's regenerations (save one) and River wasn't involved? (I'm not remotely implying she witnessed McGann to Eccleson regeneration, so get that out of your head!)
Moreover, when she met 10, she didn't immediately assume he was an earlier incarnation. In fact seemed a bit surprised that he was an earlier incarnation, and a bit miffed that he didn't already know and trust her. Thing is, why would she ever consider the possibility that he was a post-11-incarnation, if she'd seen 11 actually die?
In fact, when she looks in his eyes, and realizes that he truly is a younger incarnation of the Doctor she knew, she pretty much implies that she's been acquainted with more than one later incarnation of him, and that none were as early an incarnation as him.
Now while I know that "continuity" is a bad word in the Whoverse, most authors don't write stories that invalidate their own previous works. That is, while they're sometimes more than willing to ignore the continuity of other authors, they usually maintain a kind of "personal continuity" of their own, which guides their own projects within a series of works. I'm assuming that Moffat has a plan of some kind, and isn't going to violate any ground rules that he himself has gone out of his way to establish.
And he's pretty much established that River circa "Silence in the Library" has known several incarnations of The Doctor, all of which apparently came after Ten.
The River Song that the Doctor encounters in the library not only doesn't expect his life to end in his very next incarnation, but seemingly knows for a fact that it doesn't. And I think that Moffat going to be true to that.