Coincidentally, I recently discovered that code I landed in the mozilla repo a couple of weeks ago crashes gdb when it tries to demangle (and c++filt on the command line). Looks to be infinite recursion. It's still in the current Nightly binary.

_ZN2js18CompartmentChecker5checkIN2JS8GCVectorI4jsidLm0ENS_15TempAllocPolicyEEEEEN7mozilla8EnableIfIXsrNS7_6IsSameIDTclptcvPT_LDn0E5beginEEDTclptcvSB_LDn0E3endEEEE5valueEvE4TypeERKSA_

coming from

    template <typename Container>
    typename mozilla::EnableIf<
        mozilla::IsSame<
            decltype(((Container*)nullptr)->begin()),
            decltype(((Container*)nullptr)->end())
        >::value
    >::Type
    check(const Container& container) { ... }