[temp.param] [temp.arg.nontype] Update examples and redundant duplicated

wording to match P1907R1.

Author: zygoloid

source/templates.tex

@@ -413,9 +413,9 @@
 \begin{example}
 \begin{codeblock}
 using X = int;
-struct A { friend bool operator==(const A&, const A&) = default; };
+struct A {};
 template<const X& x, int i, A a> void f() {
-  i++;                          // error: change of template-parameter value
+  i++;                          // error: change of \grammarterm{template-parameter} value
 
   &x;                           // OK
   &i;                           // error: address of non-reference template-parameter
@@ -428,16 +428,17 @@
 \end{example}
 
 \pnum
+\begin{note}
 A non-type
 \grammarterm{template-parameter}
-shall not be declared to have floating-point or void type.
+cannot be declared to have type \cv{} \tcode{void}.
 \begin{example}
 \begin{codeblock}
-template<double d> class X;     // error
-template<double* pd> class Y;   // OK
-template<double& rd> class Z;   // OK
+template<void v> class X;       // error
+template<void* pv> class Y;     // OK
 \end{codeblock}
 \end{example}
+\end{note}
 
 \pnum
 A non-type
@@ -1233,9 +1234,10 @@
 A<&f> a;                        // selects \tcode{f(int)}
 
 template<auto n> struct B { @\commentellip@ };
-B<5> b1;                        // OK: template parameter type is \tcode{int}
-B<'a'> b2;                      // OK: template parameter type is \tcode{char}
-B<2.5> b3;                      // error: template parameter type cannot be \tcode{double}
+B<5> b1;                        // OK, template parameter type is \tcode{int}
+B<'a'> b2;                      // OK, template parameter type is \tcode{char}
+B<2.5> b3;                      // OK, template parameter type is \tcode{double}
+B<void(0)> b4;                  // error: template parameter type cannot be \tcode{void}
 \end{codeblock}
 \end{example}
 
@@ -1250,40 +1252,21 @@
   @\commentellip@
 };
 
-X<const char*, "Studebaker"> x; // error: string literal as template-argument
+X<const char*, "Studebaker"> x; // error: string literal as \grammarterm{template-argument}
+X<const char*, "Knope" + 1> x2; // error: subobject of string literal as \grammarterm{template-argument}
 
 const char p[] = "Vivisectionist";
 X<const char*, p> y;            // OK
 
 struct A {
   constexpr A(const char*) {}
-  friend bool operator==(const A&, const A&) = default;
 };
 
 X<A, "Pyrophoricity"> z;        // OK, string literal is a constructor argument to \tcode{A}
 \end{codeblock}
 \end{example}
 \end{note}
 
-\pnum
-\begin{note}
-The address of an array element or non-static data member is not an acceptable
-\grammarterm{template-argument}.
-\begin{example}
-\begin{codeblock}
-template<int* p> class X { };
-
-int a[10];
-struct S { int m; static int s; } s;
-
-X<&a[2]> x3;                    // error: address of array element
-X<&s.m> x4;                     // error: address of non-static member
-X<&s.s> x5;                     // OK: address of static member
-X<&S::s> x6;                    // OK: address of static member
-\end{codeblock}
-\end{example}
-\end{note}
-
 \pnum
 \begin{note}
 A temporary object
@@ -1296,10 +1279,16 @@
 \begin{codeblock}
 template<const int& CRI> struct B { @\commentellip@ };
 
-B<1> b2;                        // error: temporary would be required for template argument
+B<1> b1;                        // error: temporary would be required for template argument
 
 int c = 1;
-B<c> b1;                        // OK
+B<c> b2;                        // OK
+
+struct X { int n; };
+struct Y { const int &r; };
+template<Y y> struct C { @\commentellip@ };
+C<Y{X{1}.n}> c;                 // error: subobject of temporary object used to initialize
+                                // reference member of template parameter
 \end{codeblock}
 \end{example}
 \end{note}