enum to string in modern C++11 / C++14 / C++17 and future C++20

Contrary to all other similar questions, this question is about using the new C++ features.

• 2008 c Is there a simple way to convert C++ enum to string?
• 2008 c Easy way to use variables of enum types as string in C?
• 2008 c++ How to easily map c++ enums to strings
• 2008 c++ Making something both a C identifier and a string?
• 2008 c++ Is there a simple script to convert C++ enum to string?
• 2009 c++ How to use enums as flags in C++?
• 2011 c++ How to convert an enum type variable to a string?
• 2011 c++ Enum to String C++
• 2011 c++ How to convert an enum type variable to a string?
• 2012 c How to convert enum names to string in c
• 2013 c Stringifying an conditionally compiled enum in C

After reading many answers, I did not yet find any:

• Elegant way using C++11, C++14 or C++17 new features
• Or something ready-to-use in Boost
• Else something planned for C++20

Example

An example is often better than a long explanation.
You can compile and run this snippet on Coliru.
^{(Another former example is also available)}

#include <map>
#include <iostream>

struct MyClass
{
    enum class MyEnum : char {
        AAA = -8,
        BBB = '8',
        CCC = AAA + BBB
    };
};

// Replace magic() by some faster compile-time generated code
// (you're allowed to replace the return type with std::string
// if that's easier for you)
const char* magic (MyClass::MyEnum e)
{
    const std::map<MyClass::MyEnum,const char*> MyEnumStrings {
        { MyClass::MyEnum::AAA, "MyClass::MyEnum::AAA" },
        { MyClass::MyEnum::BBB, "MyClass::MyEnum::BBB" },
        { MyClass::MyEnum::CCC, "MyClass::MyEnum::CCC" }
    };
    auto   it  = MyEnumStrings.find(e);
    return it == MyEnumStrings.end() ? "Out of range" : it->second;
}

int main()
{
   std::cout << magic(MyClass::MyEnum::AAA) <<'\n';
   std::cout << magic(MyClass::MyEnum::BBB) <<'\n';
   std::cout << magic(MyClass::MyEnum::CCC) <<'\n';
}

Constraints

• Please no valueless duplication of other answers or basic link.
• Please avoid bloat macro-based answer, or try to reduce the #define overhead as minimum as possible.
• Please no manual enum -> string mapping.

Nice to have

• Support enum values starting from a number different from zero
• Support negative enum values
• Support fragmented enum values
• Support class enum (C++11)
• Support class enum : <type> having any allowed <type> (C++11)
• Compile-time (not run-time) conversions to a string,
  or at least fast execution at run-time (e.g. std::map is not a great idea…)
• constexpr (C++11, then relaxed in C++14/17/20)
• noexcept (C++11)
• C++17/C++20 friendly snippet

One possible idea could be using the C++ compiler capabilities to generate C++ code at compilation-time using meta-programming tricks based on variadic template class and constexpr functions…