#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/repetition/repeat.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/seq/size.hpp>
#include <boost/preprocessor/seq/elem.hpp>
#include <boost/preprocessor/seq/enum.hpp>
#include <boost/preprocessor/tuple/elem.hpp>
#include <boost/preprocessor/facilities/intercept.hpp>
#include <boost/mpl/bool.hpp>

#define FALSE_PARAM(_, i, data) , \
  BOOST_PP_CAT(BOOST_PP_TUPLE_ELEM(2, 1, data), i) && \
  BOOST_PP_SEQ_ELEM(i, BOOST_PP_TUPLE_ELEM(2, 0, data))

#define ASSERT_INVALID_EXPR_IMPL(vars, num_vars, expr, msg, temp) \
  struct temp { \
    template<BOOST_PP_ENUM_PARAMS(num_vars, typename temp)> \
    static boost::mpl::false_ is_ok(int* \
      BOOST_PP_REPEAT(num_vars, FALSE_PARAM, (vars, temp)), \
      decltype(expr)* = 0); \
    template<BOOST_PP_ENUM_PARAMS(num_vars, typename temp)> \
    static boost::mpl::true_ is_ok(bool, \
      BOOST_PP_ENUM_BINARY_PARAMS(num_vars, temp, && BOOST_PP_INTERCEPT)); \
    typedef decltype(is_ok((int*)0, BOOST_PP_SEQ_ENUM(vars))) test_type; \
  }; \
  static_assert(temp::test_type::value, msg);

#define ASSERT_INVALID_EXPR(vars, expr, msg) \
  ASSERT_INVALID_EXPR_IMPL(vars, BOOST_PP_SEQ_SIZE(vars), expr, msg, \
    BOOST_PP_CAT(invalid_expr_test, __LINE__))

template<typename T, typename U>
struct A {
  T x;
  U y;
  ASSERT_INVALID_EXPR((x), x+y, "Can add x and y; bad");
};

int main()
{
  A<char*, char*>();
  A<int, int>(); // generates assertion failure
}