Notes from the September, 2013 meeting:

This issue is being handled editorially and is being placed in "review" status to ensure that the change has been made.

The example in 7.7 [expr.const] paragraph 6,

  struct A {
    constexpr A(int i) : val(i) { }
    constexpr operator int() { return val; }
    constexpr operator long() { return 43; }
  private:
    int val;
  };
  template<int> struct X { };
  constexpr A a = 42;
  X<a> x;               // OK: unique conversion to int
  int ary[a];           // error: ambiguous conversion

is no longer correct now that constexpr does not imply const for member functions, since the conversion functions cannot be invoked for the constant a.