From Jason Turner

[temp.class.order]

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  #### Partial ordering of class template specializations <a id="temp.class.order">[[temp.class.order]]</a>
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- For two class template partial specializations, the first is at least as
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- specialized as the second if, given the following rewrite to two
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- function templates, the first function template is at least as
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- specialized as the second according to the ordering rules for function
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- templates ([[temp.func.order]]):
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- - the first function template has the same template parameters as the
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- first partial specialization and has a single function parameter whose
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- type is a class template specialization with the template arguments of
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- the first partial specialization, and
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- - the second function template has the same template parameters as the
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- second partial specialization and has a single function parameter
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- whose type is a class template specialization with the template
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- arguments of the second partial specialization.
 
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  ``` cpp
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  template<int I, int J, class T> class X { };
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  template<int I, int J> class X<I, J, int> { }; // #1
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  template<int I> class X<I, I, int> { }; // #2
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- template<int I, int J> void f(X<I, J, int>); // A
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- template<int I> void f(X<I, I, int>); // B
 
 
 
 
 
 
 
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  ```
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- The partial specialization `#2` is more specialized than the partial
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- specialization `#1` because the function template `B` is more
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- specialized than the function template `A` according to the ordering
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- rules for function templates.
 
 
 
 
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  #### Partial ordering of class template specializations <a id="temp.class.order">[[temp.class.order]]</a>
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+ For two class template partial specializations, the first is *more
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+ specialized* than the second if, given the following rewrite to two
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+ function templates, the first function template is more specialized than
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+ the second according to the ordering rules for function templates (
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+ [[temp.func.order]]):
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+ - Each of the two function templates has the same template parameters as
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+ the corresponding partial specialization.
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+ - Each function template has a single function parameter whose type is a
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+ class template specialization where the template arguments are the
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+ corresponding template parameters from the function template for each
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+ template argument in the *template-argument-list* of the
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+ *simple-template-id* of the partial specialization.
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+
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+ [*Example 1*:
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  ``` cpp
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  template<int I, int J, class T> class X { };
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  template<int I, int J> class X<I, J, int> { }; // #1
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  template<int I> class X<I, I, int> { }; // #2
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+ template<int I0, int J0> void f(X<I0, J0, int>); // A
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+ template<int I0> void f(X<I0, I0, int>); // B
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+
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+ template <auto v> class Y { };
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+ template <auto* p> class Y<p> { }; // #3
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+ template <auto** pp> class Y<pp> { }; // #4
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+
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+ template <auto* p0> void g(Y<p0>); // C
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+ template <auto** pp0> void g(Y<pp0>); // D
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  ```
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+ According to the ordering rules for function templates, the function
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+ template *B* is more specialized than the function template *A* and the
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+ function template *D* is more specialized than the function template
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+ *C*. Therefore, the partial specialization \#2 is more specialized than
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+ the partial specialization \#1 and the partial specialization \#4 is
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+ more specialized than the partial specialization \#3.
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+
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+ — *end example*]
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