title: Will Concepts replace SFINAE?
body: <p>Concepts likely to be in the C++ standard (C++17, or maybe C++20).</p>
  
  <p>So I wonder if this new feature can completely replace SFINAE, or it's just a small version of SFINAE with nice error reports and type checking.</p>
  
  <p>Are there any cases when SFINAE is the only choice instead of using Concepts?</p>