To be fair, using Xcode 10.1 with the legacy build system seems to work perfectly well (unless you need to build 32-bit apps).
It works alright… There’s no dedicated sanitizer UI, but AppCode seems to be smart enough to turn file references in the logged output into clickable links, so you can still inspect the allocation/deallocation stacks fairly easily. The debugger pauses on issues too, which is handy.
That problem is unrelated to Xcode 10. See these topics:
Ok i’m for a new project. Meanwhile where do i find the JUCE_VST3_CAN_REPLACE_VST2 statement to set to 0 ?