Show Indent Guide Lines In Xcode
In Xcode 10, if you press Command and hover over the structure it will show what is desired. It is not permanent but it helps.
Xcode doesn't have this feature (not that I'm aware of) , but it has a (kinda) similar one. If you look closely in a method with a few loops or if structures, each structure gets a black tint on the left side of the editing area (right next to the line numbers).
You can collapse or expand the functions as needed.
I've been searching the same but the most similar solution on Xcode 11 is shows invisibles
