Why is partial specialization of a nested class template allowed, while complete isn't?

Question

    template struct A {                                                                                                    
        template

        

Answer 1

You can work around this behavior by delegating the real work to another structure though:

namespace detail
{
  template 
  struct InnerImpl {};
}

template 
struct Outer
{
  template 
  struct Inner: detail::InnerImpl
  {
  };
};

Now you can specialize InnerImpl as you wish