I've been struggling with this for some time now. Xcode simply does not show anything in the variables view of the Debug area. It's not that the variables are listed but don't show any values, there is always absolutely nothing in that box (regardless of scope : All/ Auto/ Local Variables). I've made the following futile attempts to resolve this issuse :
1. Made sure target scheme's build configuration for Run is set to Debug.
2. In target Build Settings, set optimizations to None.
3. Clean code.
4. Clear derived data and module cache.
5. Re-installed Xcode (including testing with previous version Xcode 10)
I'm using Swift only (no obj-c headers). No pods. No external frameworks.
I found the Variables view to be an extremely helpful feature of Xcode but I've been deprived of that tool now. Any direction or support is much appreciated.