Just in case: Spoilers ahead up to chapter 14 of Re
Up to the latest chapter of Re (chapter 14 atm), Kaneki is within Haise. To how much of an extent is unknown. We have evidence that the white-haired Kaneki is present in Haise's mind as well as in an inheritance of his abilities. Further chapters also reveal memory déjà vu occurring with overlap from Kaneki's memories into Haise's. Haise even recognizes the possibility of his "other self's" memories coming back and ponders how they will interact with his. Furthermore, Haise is indicated to have an extremely high RC cell count and they also point out that if he was to turn he would be ranked as an SS rank ghoul. Kaneki was a powerful ghoul in the original TG run and was ranked similarly (or soon to be). Comparing these rough levels, we can place Haise and Kaneki on similar pedestals of power. Haise, when fighting Serpent, is shown borrowing "power" from, who is most likely, white-haired Kaneki. This sudden boost in power, which enables him to defeat Serpent, puts him on a level of ferocity similar to Kaneki, which further validates the possibility of his being our one-eyed favourite. Another red herring is when "white-haired Kaneki" is depicted giving Haise his power he is shown sitting in a chair. Thinking back to the original TG we first see the white-haired phenom emerging ferocious from a chair, born anew. The chair can represent the origin point of the white-haired version so could it not also function as a resting place, or better yet, a new birth place?
These points clearly establish that Haise and Kaneki are intrinsically linked. Is Kaneki Haise? At the moment, it's not confirmed but it's about as close as we're going to get. A theory floating around appoints that Kaneki's organs could have been transplanted into Haise. This could also explain Haise's hallucinations of Kaneki (similar to Rize/Kaneki). This is a plausible theory as the CCG has a penchant for harvesting ghoul parts and Kaneki would be a gold mine with his regenerative abilities. What doesn't work is the physical similarities. Haise looks and symbolizes a "new Kaneki". His black-encroaching-on-white hair is styled and looks half way in between the previous two Kaneki's. Two members of Pierrot also pick him out as Kaneki in a (very convincing) disguise. They clearly recognize him. The last piece in the puzzle is at the end of The original TG run a vast sky is depicts a person with a suitcase and the words "He'll return to Anteiku some day" (Touka referring to Kaneki returning). We've established that Kaneki is not in the briefcase so it has to be the individual that they're referring to. A man that bears striking silhouette similarities to Haise.
At this point if Kaneki is dead then we've be lead on the largest goose chase in manga. I think it's safe to assume that Haise is Kaneki.
What we really want to know is what happened to Hide?
TLDR: Nothing said outright but, at this point, it's a 90% Kaneki-is-Haise guarantee.