template-based wrapper for any callable with signature + metadata traits

callable.hpp

#pragma once

#include <type_traits>
#include <functional>

template<typename TCallable, typename TSignature>
constexpr bool is_callable_as_v = std::is_constructible<std::function<TSignature>, TCallable>::value;

template<
    typename TCallable,
    typename TSignature,
    typename = std::enable_if_t<is_callable_as_v<TCallable, TSignature>>>
using Callable = TCallable;

template<typename TCallable>
struct CallableMetadata
    : CallableMetadata<decltype(&TCallable::operator())>
{
};

template<class TClass, typename TReturn, typename... TArgs>
struct CallableMetadata<TReturn(TClass::*)(TArgs...)>
{
    using class_t = TClass;
    using return_t = TReturn;
    using args_tuple_t = std::tuple<TArgs...>;
    using ptr_t = TReturn(*)(TArgs...);

    // Beware! this function makes a copy of the closure! and of the arguments when called!
    static ptr_t generatePointer(const TClass& closure)
    {
        static TClass staticClosureCopy = closure;

        return [](TArgs... args)
        {
            return staticClosureCopy(args...);
        };
    }
};

template<class TClass, typename TReturn, typename... TArgs>
struct CallableMetadata<TReturn(TClass::*)(TArgs...) const>
{
    using class_t = TClass;
    using return_t = TReturn;
    using args_tuple_t = std::tuple<TArgs...>;
    using ptr_t = TReturn(*)(TArgs...) const;

    // Beware! this function makes a copy of the closure! and of the arguments when called!
    static ptr_t generatePointer(const TClass& closure)
    {
        static TClass staticClosureCopy = closure;

        return [](TArgs... args)
        {
            return staticClosureCopy(args...);
        };
    }
};

// Beware! this function makes a copy of the closure! and of the arguments when called!
template<typename TCallable>
auto* callableToPointer(const TCallable& callable)
{
    return CallableMetadata<TCallable>::generatePointer(callable);
}

Clang 12 is complaining:

error: pointer to function type cannot have 'const' qualifier

on line 47

I removed the "const" qualifier, and it seems to work, but maybe I am missing something?

I have no idea tbh, i wrote this a long time ago