title: Why is there no enumeration concept in C++ 20?
body: <p>I am trying to update some older code to the coming C++20 language using current GCC10.</p>
  
  <p>I was not able to update some templates because they used a <code>std::enable_if&lt;std::is_enum_v&lt;T&gt;&gt;</code> condition and there is no <code>std::enumeration</code> concept defined in C++20.</p>
  
  <p>Of course I can define my own concept but still it makes me wonder why C++20 does not implement all existing type traits as concepts.</p>
  
  <p>Why is this? Did I miss something important?</p>