Now and then the debugger starts acting flaky, losing track of breakpoints and wandering all over the place, no matter how you step into, over, or out the code. At other times, the compiler starts going wild.

Fix: Try one or more of these:

1. Quit XCode, relaunch, and try again.
2. Clean, rebuild, and try again.
3. Create a new project from scratch, copy all the source files into the new project, and try again.

FWIW, #3 is the only one that works reliably for me.