C++20 allows non-trivial constexpr constructors, so this BadUnfortunateError check passes unexpectedly when compiled as C++20:
> error: 'error' diagnostics expected but not seen: build/clang-plugin/tests/TestTrivialCtorDtor.cpp Line 81: class 'BadUnfortunateError' must have trivial constructors and destructors
This constexpr constructor check was added in bug 1226376.
Differential Revision: https://phabricator.services.mozilla.com/D161951