In chromium, QUIC_BUG is implemented as an alias for QUIC_LOG(DFATAL).   This is useful if unexpected code paths are hit in unit tests, but unlikely to surface in any reliable way if such code paths are hit in production.

One option would be to devise a way to populate a histogram to track QUIC_BUG occurrences.  The difficult part would be how to enumerate the QUIC_BUGs without extending the current QUIC_BUG interface.

Another option is to trigger a crash, as in a CHECK failure.  The stack trace would identify the specific BUG clearly, and we should catch active QUIC_BUGs well before they reach STABLE. 

I was proposing something like the histogram in the discussion that motivated filing this bug, but as I write I'm more inclined that crashing is the better solution.