(From submissions #725 and #730.)

The rewrite of iterating expansion statements contains:

  static constexpr auto iter = begin + i;

Furthermore, the rewrite contains

  for (auto i = begin ; i != end ; ++i, ++result);

Furthermore, because of the use of static in the rewrite, the example in 8.7 [stmt.jump] paragraph 7 is ill-formed.

Possible resolution:

1. Change in 8.7 [stmt.jump] bullet 5.2 as follows:

   Otherwise, if S is an iterating expansion statement, S is equivalent to:

     {
       init-statement
       static constexpr auto&& range = expansion-initializer ;
       static constexpr auto begin = begin-expr;    // see 8.6.5 [stmt.ranged]
       static constexpr auto end = end-expr;        // see 8.6.5 [stmt.ranged]
       S0
       .
       .
       .
       SN-1
     }
   

   where N is the result of evaluating the expression

     [] consteval {
       std::ptrdiff_t result = 0;
       for (auto i = begin ; i != end ; ++i, ++result) ++result;
       return result;    // distance from begin to end
     }()
   

   and Si is

     {
       static constexpr auto iter = begin + i i;
       for-range-declaration = *iter ;
       compound-statement
     }
   

   The variables range , begin , end , and iter are defined for exposition only. The identifier i is considered to be a prvalue of type std::ptrdiff_t. [Note 1 : The instantiation is ill-formed if range is not a constant expression (7.7 [expr.const]). -- end note]

2. Change in 8.7 [stmt.jump] paragraph 7 as follows:

   [ Example 2:

     consteval int f() {
       static constexpr std::array<int, 3> arr {1, 2, 3};
       int result = 0;
       template for (constexpr int s : arr) {      // OK, iterating expansion statement
         result += sizeof(char[s]);
       }
       return result;
     }
     static_assert(f() == 6);
   

   —end example]