Is this legal?

struct X { struct Y { /* ... */ }; };
extern struct X Y;
struct X ::Y;  // trying to refer to the 'Y' declared on the previous line

[I understand the '::' is not needed and that the whitespace is not
significant -- those are not my point.]

The syntax in the Dec 1996 working paper seems ambiguous here.  How does
one decide if the decl-specifier in last line is 'struct X' or 'struct
X::Y'?  In the first case the declarator-id would be '::Y' and in the
second it would be missing.

I expected to find a rule to disambiguate saying that nested-name-specifier
was "greedy" or some such but I couldn't find any.

Section 8.3 [Meaning of declarators, dcl.meaning] does say the following
which seems to indicate that a declarator-id '::Y' would be ill-formed
except that the note implies that '::' can be used to refer to names in
global scope so perhaps I don't really grasp the meaning of the paragraph.
I also don't understand the rationale behind making the code in the example
illegal.

  A declarator-id shall not be
  qualified  except  for   the   definition   of   a   member   function
  (_class.mfct_)  or static data member (_class.static_) or nested class
  (_class.nest_) outside  of  its  class,  the  definition  or  explicit
  instantiation  of  a function, variable or class member of a namespace
  outside of its namespace, or the definition of a  previously  declared
  explicit  specialization  outside of its namespace, or the declaration
  of a friend function that is a member of another  class  or  namespace
  (_class.friend_).   When  the declarator-id is qualified, the declara-
  tion shall refer to a previously  declared  member  of  the  class  or
  namespace to which the qualifier refers, and the member shall not have
  been introduced by a using-declaration in the scope of  the  class  or
  namespace nominated by the nested-name-specifier of the declarator-id.
  [Note: if the qualifier is the global ::  scope  resolution  operator,
  the  declarator-id  refers  to a name declared in the global namespace
  scope.  ] In the qualified declarator-id for a class or namespace mem-
  ber  definition  that  appears outside of the member's class or names-
  pace, the nested-name-specifier shall not name any of  the  namespaces
  that enclose the member's definition.  [Example:
          namespace A {
                  struct B {
                          void f();
                  };
                  void A::B::f() { } // ill-formed: the declarator must not be
                                     // qualified with A::
          }
   --end example]

I do not believe that just because a declarator-id '::Y' is ill-formed
means that the ambiguity can be resolved.

I appeal to those more worthy than I to give me a clue.

Thanks,
         --scott
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