As described in bug 12763, a few C++ sources in LibreOffice trigger the
following assert, when compiling in C++0x or C++11 mode:

Assertion failed: (EST != EST_Delayed && EST != EST_Uninstantiated),
function isNothrow, file tools/clang/include/clang/AST/Type.h, line
2873.

Richard Smith reduced the testcase to:

template<bool B> struct T {
  virtual void f() noexcept (B);
};
struct X : public T<true> {
  virtual void g();
};
void X::g() {}