For some reason, depending on the compiler I use, I get an error
message on my program. The compiler that's causing my grief is g++,
while MSVC seems to do it fine, and I think Sun's CC does it, too -
have I stumbled on a compiler bug, or are the otehrs allowing me
something that I should not be allowed to do?

The code follows:
#include <vector.h>
#include <pair.h>

template <class T>
class ptr : public pair<int, T*>
{
public:
    inline ptr(T &d);
    inline ptr();
};

template <class T>
inline ptr<T>::ptr(T & d)
        : pair<int, T*>(d.id(), (T*)0)
{
    second=static_cast<T*>(d.refer_to(*this)); // 'this' doesn't exist before
}

class graph_edge;
class graph_node
{
public:
    vector<ptr<graph_edge> > edges;

    inline graph_edge* refer_to( graph_edge &edge );
};

class graph_edge
{
public:
    vector<ptr<graph_node> > nodes;

    inline graph_node* refer_to( graph_node &node );
};

And this is what g++ says:

bug.cpp: In method `ptr<graph_edge>::ptr(graph_edge &)':
bug.cpp:14: cannot lookup method in incomplete type `graph_edge'
bug.cpp:15: in base initialization for class `pair<int,graph_edge *>'
bug.cpp:16: cannot lookup method in incomplete type `graph_edge'
bug.cpp: In method `ptr<graph_node>::ptr(graph_node &)':
bug.cpp:14: no member function `graph_node::id()' defined
bug.cpp:15: in base initialization for class `pair<int,graph_node *>'
bug.cpp:16: bad argument 1 for function `class graph_edge *
graph_node::refer_to
(class graph_edge &)' (type was class ptr<graph_node>)

What's going on here?

Enno
--

Enno Rehling  Kilianstra=DFe 129a  33098 Paderborn  Germany
rehling@usa.net  http://hrz.uni-paderborn.de/~q09960/public/
Tel/Fax: Int+ 49 (0) 5251-760796
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>>>>> Enno Rehling <enno@uni-paderborn.de> writes:

> For some reason, depending on the compiler I use, I get an error
> message on my program. The compiler that's causing my grief is g++,

> bug.cpp: In method `ptr<graph_edge>::ptr(graph_edge &)':
> bug.cpp:14: cannot lookup method in incomplete type `graph_edge'
> bug.cpp:15: in base initialization for class `pair<int,graph_edge *>'

g++ 2.7.2 instantiates class templates and their methods earlier than it
should, which can cause problems like this.  This bug will be fixed in 2.8.

Jason
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