Failing to get warning C4482 in VS-2017

Question

In Visual Studio 2017 (15.9.11) I fail to get warning C4482 on the code below.

I also tried to set:

• Disable Language Extensions - Yes
• Conformance mode - Yes
• EnableAllWarning (/Wall)
• using pragma (and also through project settings) to force this warning as error

Any idea why it does not work?

// Trying also to force the warning as an error
#pragma warning(error : 4482)

class CA
{
    enum COLOR
    {
        RED = 0
    };

    void foo()
    {
        COLOR c = CA::COLOR::RED;   // Expecting warning C4482
        c = COLOR::RED;             // Expecting warning C4482
    }
};

Answer 1

Presumably something changed in the C++ standard.
The documentation notes:

"This warning is not generated by Visual C++ compilers that support C++11."

Answer 2

It's valid, standard-conforming code, as of C++11 which added the following paragraph:

[basic.lookup.qual]/5 A name prefixed by a nested-name-specifier that nominates an enumeration type shall represent an enumerator of that enumeration.

To remove all doubt, there's a (non-normative) example in [dcl.enum]:

enum direction { left=’l’, right=’r’ };

void g() {
  direction d; // OK
  d = left; // OK
  d = direction::right; // OK
}

enum class altitude { high=’h’, low=’l’ };

void h() {
  altitude a; // OK
  a = high; // error: high not in scope
  a = altitude::low; // OK
}