Proposed resolution (November, 2009):

Change 12.6 [over.literal] paragraph 3 as follows:

The declaration of a literal operator shall have a parameter-declaration-clause equivalent to one of the following:

  const char*
  unsigned long long int
  long double
  char
  wchar_t
  char16_t
  char32_t
  const char*, std::size_t
  const wchar_t*, std::size_t
  const char16_t*, std::size_t
  const char32_t*, std::size_t