Use of overloaded operator== in BOOST_TEST() is ambiguous

[kamo.tanabota@…]

I'm unable to compile the following code due to ambiguity of opertor== overloads.

#define BOOST_TEST_MODULE mytest
#include <boost/test/included/unit_test.hpp>

struct S {
    template <class T>
    S(T&&) {}
};

bool operator==(S const&, S const&) { return true; }

template <class T>
bool operator==(T const&, S const&) { return true; }

BOOST_AUTO_TEST_CASE(test1)
{
    auto const s = S{"hoge"};
    BOOST_TEST(s == 4);
}

This seems to happen if there is an overload taking a template parameter for the left operand.

Using boost::iterator_range, instead of the class S, results in same issue.

[anonymous]

I do not think we can do anything about this. Templated operator== will always conflict with my templated operator== method.

You can alway work around the issue with pair of extra ().

[Raffi Enficiaud]

Workaround mentioned in the documentation of BOOST_TEST