Q:

Is there an invisible wall above a certain building in the Metro Kingdom?

In the Metro Kingdom, there is a small area in which you ride a motor scooter with a dinosaur chasing you.  The "Motor Scooter: Escape!" and "Big Jump: Escape!" Power Moons are located here.  At the end of this section, there is a jump, where the dinosaur falls into a pit while you escape.  After this jump, the third building on the left wall is short enough that you could feasibly reach it with a well-timed jump off of the scooter.  
I have tried to make it to the top of this building many times, since there are often secrets in places like this in the game.  Specifically, I was looking for Power Moons and Purple Coins.  I have not been able to land the jump, or grab the ledge, even when the scooter is right next to this building, at the same height as the roof.  
In my last attempt, it looked to me like I was wall-sliding down the empty space above this building!  Is there an invisible wall there, or was I mistaken in what I was seeing?  I'd much rather not waste any more time on something impossible.  

A:

Yes, there is an invisible wall at that location.
A recent video posted on Reddit clearly shows Mario wall sliding, then diving into an invisible wall above the building in question.  
Also, as Fredy31 suggested in the comments, I have returned to the area (after completing the main story) and Cappy confirmed that there is nothing else to find in the area, so there can be no Power Moons or Purple Coins above that building.  

