Steps to repro: 1. Pause inside a function with |return <expr>;| on the last line. 2. Step over each statement until the return. 3. Step over the return statement. At the end of step 3, the debugger is stepped "past" the return statement. How this is shown to the user seems inconsistent. Sometimes, the debugger implicitly "steps out" to the callee's call frame, while other times it seems to step past the return statement without stepping out. I haven't peeked at the protocol traffic to see what commands are actually being emitted. It may be the case that some of the step over clicks were not being sent to the backend somehow. To prevent this sort of race, we could add a debouncing animation to the stepping buttons that makes it clearer when the debugger command has been processed.
<rdar://problem/19281478>
I have a fix for this. I'll likely duplicate to a more general bug addressing many stepping issues.
Fixed by: bug 155325 <https://trac.webkit.org/changeset/206652> *** This bug has been marked as a duplicate of bug 155325 ***