[Bug c++/19188] New: friend funtion inside a template class seems to have a problem

["max656 at hotmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

A template class(tstack class) has a singly-linked list "struct" declaration in
private section.
Another template class(tstackIterator) - iterator class is declared and defined
in global space.
If the iterator template class trys to get access to the linked list structure
inside the  previous class with a friend statement declared in   the previous
class, it does not work. It behaves in much the same way as without friend
declaration. The following code shows this:
//: TSTACK.H -- Stack using templates
#ifndef TSTACK_H_
#define TSTACK_H_

// Some implementations require this:
template<class T> class tstackIterator;


template<class T> 
class tstack {

 struct link {

    T* data;
    link* next;

    link(T* Data, link* Next){
      data = Data;
      next = Next;
    }
 } * head;
  int owns;



public:

  tstack(int Owns = 1) : head(0), owns(Owns) {}
  ~tstack();
  void push(T* Data) {
    head = new link(Data,head);
  }
  T* peek() const { return head->data; }
  T* pop();
  int Owns() const { return owns; }
  void Owns(int newownership) {
    owns = newownership;
  }

  friend class tstackIterator<T>;

};

template<class T>
T* tstack<T>::pop() {
  if(head == 0) return 0;
  T* result = head->data;
  link* oldHead = head;
  head = head->next;
  delete oldHead;
  return result;
}

template<class T>
tstack<T>::~tstack() {
  link* cursor = head;
  while(head) {
    cursor = cursor->next;
    // Conditional cleanup of data:
    if(owns) delete head->data;
    delete head;
    head = cursor;
  }
}

template<class T>
class tstackIterator {
////////////////////////////////////
  tstack<T>::link* p; // this is line 68

// when it is compiled, g++ 3.4.1 give some error message but it does not make
//sense in terms of languae. but the version g++ (GCC) 3.2.3 20030502 works fine 
// except that it gives a warning saying "tstack.h:68: warning: `typename
//tstack<T>::link' is implicitly a typename"
//The Error message is attached to the bottom
///////////////////////////////////
public:
  tstackIterator(const tstack<T>& tl)
    : p(tl.head) {}
  tstackIterator(const tstackIterator& tl)
    : p(tl.p) {}
  // operator++ returns boolean indicating end:
  int operator++() {
    if(p->next)
      p = p->next;
    else p = 0; // Indicates end of list
    return int(p);
  }
  int operator++(int) { return operator++(); }
  // Smart pointer:
  T* operator->() const {
    if(!p) return 0;
    return p->data;
  }
  T* current() const {
    if(!p) return 0;
    return p->data;
  }
  // int conversion for conditional test:
  operator int() const { return p ? 1 : 0; }
};
#endif // TSTACK_H_

////////////////////////////////////////////
the compiler complaints are as follows:

In file included from tstktst.cpp:2:
../14/tstack.h:68: error: expected `;' before '*' token
../14/tstack.h: In constructor `tstackIterator<T>::tstackIterator(const
tstack<T>&)':
../14/tstack.h:71: error: class `tstackIterator<T>' does not have any field
named `p'
../14/tstack.h: In copy constructor `tstackIterator<T>::tstackIterator(const
tstackIterator<T>&)':
../14/tstack.h:73: error: class `tstackIterator<T>' does not have any field
named `p'
../14/tstack.h: In member function `int tstackIterator<T>::operator++()':
../14/tstack.h:76: error: `p' undeclared (first use this function)
../14/tstack.h:76: error: (Each undeclared identifier is reported only once for
each function it appears in.)
../14/tstack.h: In member function `T* tstackIterator<T>::operator->() const':
../14/tstack.h:84: error: `p' undeclared (first use this function)
../14/tstack.h: In member function `T* tstackIterator<T>::current() const':
../14/tstack.h:88: error: `p' undeclared (first use this function)
../14/tstack.h: In member function `tstackIterator<T>::operator int() const':
../14/tstack.h:92: error: `p' undeclared (first use this function)

-- 
           Summary: friend funtion inside a template class seems to have a
                    problem
           Product: gcc
           Version: 3.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: max656 at hotmail dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19188