Question

This compiles on GCC 4.6 but doesn’t with VS2010 sp1:
Is it my fault or VS screwed up again?

 #include "stdafx.h"

enum Attribute{red_att,black_att,key_att,value_att};

struct Color{};



template<enum Attribute>
struct Tag_Value;

template<>
struct Tag_Value<red_att>
{
    typedef Color type;
};

int main()
{

    return 0;
}

Errors:
error C2599: 'Attribute' : forward declaration of enum type is not allowed

error C2440: 'specialization' : cannot convert from 'Attribute' to 'Attribute'

Answer 1

I’m not certain what the exact problem is—my guess is that it is treating enum Attribute as the beginning of a new enum declaration… perhaps as a member of Tag_Value. So you have two Attribute enums and it won’t let you specialize one with the other.

To fix, just get rid of the enum:

template<enum Attribute> struct Tag_Value;

to this:

template<Attribute> struct Tag_Value;