Merge dependencies on MRs touching same code

Let’s assume 2 series/MR touching same code:
Series A
Series B that is built on top

Submitting pull request for B means, that it will include A as well, because B can’t be submitted independently.

Presumably, I can still set merge dependency for B. MR for A goes through review, some changes are made (let’s say one patch is dropped) and then it’s merged.

What happens to MR for B? Will gitlab notice than the dependency is on “old A”? Or would it allow to merge B (assuming there are no conflicts)?