WTF?
Seen in a Safari crash report today:
Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 com.apple.WebCore 0x00007fff849031b1 bool
WTF::HashTable
WTF::PairFirstExtractor
WTF::PairHashTraits
WTF::HashTraits
WTF::HashTraits
WTF, indeed.