Friend declaration for template class in C++

#include <iostream>

class MyClass {
 public:
  template <typename U>
  friend class MyTemplateClass<U>;
};

int main() { return 0; }

The code provided above, tries to declare MyTemplateClass as a friend class to MyClass.

But, the issue arises when the compiler misinterprets it as specialization of template class MyTemplateClass which clearly, is not intended?

This works:

template <typename U>
friend class MyTemplateClass;

I do not understand why one would declare a type variable U, but would not use it in the friend declaration, If the purpose was to indicate that MyTemplateClass is a template class, then why can’t we directly use this?

template <>
friend class MyTemplateClass;

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