Wrap each element in variadic macro with an expression

Problem:

I'm looking to write a variadic macro

#define WRAP(token, ...) 

which, when called with a token and N arguments

WRAP(decltype, a, b, c)

will expand into a comma-separated list of the arguments wrapped in the token

decltype(a), decltype(b), decltype(c)

This would allow me to write something like the following:

#define MACRO(...) \
    Class< WRAP(decltype, __VA_ARGS__) >::Function();

If I call it as follows:

MACRO(a, b, c)

it would result in:

Class<decltype(a), decltype(b), decltype(c)>::Function(0;

I have no idea how to achieve this. Is it possible? Perhaps with BOOST_PP or some such?

Motivation:

I have a macro for logging:

#define LOG(fmt, ...) \
    logger::instance().push(__FUNCTION__, fmt, __VA_ARGS__);

I have a variadic class template which is able to verify the arguments match the provided format string

template<typename... Ts>
struct Format
{
    template<std::size_t N>
    static constexpr bool check(const char (&fmt)[N], std::size_t n);
};

If I define a macro with a fixed number of arguments I can call my format checking function:

#define LOG(fmt, a) \
    static_assert(Format<decltype(a1)>::check(fmt, 0), ""); \
    logger::instance().push(__FUNCTION__, fmt, a);

However, if I use a variadic macro, this won't work for more than 1 argument:

#define LOG(fmt, ...) \
    static_assert(Format<decltype(__VA_ARGS__)>::check(fmt, 0), ""); \
    logger::instance().push(__FUNCTION__, fmt, __VA_ARGS__);

That's because decltype(__VA_ARGS__) is obviously invalid syntax.

to fix it, I need to expand __VA_ARGS__ into decltype(a1), decltype(a2), decltype(a3)