This is probably a very simple question, but I think its interesting.
What I would think, based on my intuition (which I think is correct in this case) is that $$\int \frac {dy}{dx}=y$$ However, to me it doesn't seem like there is something you are "integrating with respect to", meaning $$\int \frac {dy}{dx}(?)$$
doesn't have an extra d(something) tacked on to the end, like most other antiderivatives do.
If you tried to make the "dy" the thing you "tacked on", then it would become $$\int \frac 1{dx}dy$$ Which doesn't make any sense to me at all.
So, my question is, if you were trying to solve this without simply recognizing that the antiderivative of a derivative is just the function itself, then how would you solve it?
Apologies for this question being very vague.
Yes, you have to find an antiderivative with respect to something.
Since it is unspecified, the antiderivative of $\;\frac{\mathrm d y}{\mathrm d x}\;$ will implicitly be made with respect to the same variable of derivation. $x$.
$$\int \dfrac{\mathrm d y}{\mathrm d x}\mathrm d x = y+c$$
What else can you do?