Start the manual test at WebCore/manual-tests/inspector/debugger-step-on-for-statements.html Use 'Step into' and 'Step out' to enter and exit all of the functions on the 'for' line (e.g. initialize(), condition(), increment()). You will step in and out of increment() and initialize() but skip condition(). You can step into condition() if, when you are in increment() or initialize(), you press 'step-into' instead of 'step-out'
I've been running into this bug lately, especially stepping into complicated expressions with multiple calls.
*** Bug 19277 has been marked as a duplicate of this bug. ***
<rdar://problem/19281609>
*** This bug has been marked as a duplicate of bug 155325 ***