c++/7965: Mistaken attempt to call a class template default constructor

[nmusatti@comm2000.it]

>Number:         7965
>Category:       c++
>Synopsis:       Mistaken attempt to call a class template default constructor
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Wed Sep 18 00:16:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Nicola Musatti
>Release:        gcc version 3.2 (mingw special 20020817-1)
>Organization:
>Environment:
Windows 2000
>Description:
Compilation of the enclosed source results in the following error messages:

ConcreteClass.cpp: In function `int main()':
ConcreteClass.cpp:34: no matching function for call to `DirectAttribute<A,
   double>::DirectAttribute()'
ConcreteClass.cpp:4: candidates are: DirectAttribute<A,
   double>::DirectAttribute(const DirectAttribute<A, double>&)
ConcreteClass.cpp:8:                 DirectAttribute<C, T>::DirectAttribute(T
   C::*) [with C = A, T = double]
ConcreteClass.cpp:34: warning: unused variable `ConcreteClass<A> metaA'

Apparently an attempt is made to generate a (spurious) call to DirectAttribute's default constructor. The problem disappears if DirectAttribute's private member is removed (but not the constructor's argument).
>How-To-Repeat:
Compile the following code:

template <class C, typename T>
class DirectAttribute 
{
	public:
    	typedef T C::* MemberType;

    	DirectAttribute(MemberType m) : member(m) {}

    private:
    	MemberType member;
};

struct A
{
        double f;
};

template <class C> class ConcreteClass
{
};

template <> class ConcreteClass<A>
{
    public:
       ConcreteClass() : f1(&A::f) {}

    private:
    	DirectAttribute<A,double> f1;
};

int main()
{
	ConcreteClass<A> metaA;
}
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: