wstring comparions fails to compile for C++20 MSVC Windows

[gruenedd]

TEST_CASE("WString")
{
    std::wstring s1, s2;
    CHECK_EQ(s1, s2); // Also fails:  CHECK(s1 == s2);
}

Results in: doctest.h(1155): error C2672 "<<" (overload not found error)

Environment

Windows 10, MSVC, Visual Studio Version 17.6.4 cl.exe version 19.36.32535 (64 bit) doctest version 2.4.11 C++ language standard: C++20 (C++17 works)