Q130551: FIX: C2974 When Explicitly Call Class Template(‘s) Destructor

Article: Q130551
Product(s): Microsoft C Compiler
Version(s): 2.0,2.1
Operating System(s): 
Keyword(s): kbbuglist kbfixlist
Last Modified: 25-JUL-2001

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The information in this article applies to:

- Microsoft C/C++ Compiler (CL.EXE), included with:
   - *EDITOR Please do not choose this product*Microsoft Visual C++ 32-bit Edition* use 241, 265, 225, versions 2.0, 2.1 
-------------------------------------------------------------------------------

SYMPTOMS
========

When you explicitly call a class template destructor, and the class object is
instantiated with a user defined class in a C++ program, the compiler generates
the following compiler errors:

  Error C2974 : 'B' : invalid template actual argument '#1', type expected

  Error C2039 : 'B<int>' : is not a member of 'B<class A>'

For example, this can happen when you use MFC's collection classes and need to
overload the DestroyElement() helper function, in which the class destructor can
be explicitly called.

RESOLUTION
==========

The following code can be used to work around the problem.

Problem:

    B<A> a;
     a.B<A>::~B();

Workaround:

     B<A> a;
     a.B< class A >::~B();

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This problem was fixed in Microsoft Visual C++,
32-bit Edition, version 4.0.

MORE INFORMATION
================

Sample Code to Demonstrate Problem
----------------------------------

  /* Compile options needed: none.
  */ 

  class A
  {
  public:
     A() {}
     ~A() {}
  };

  template < class T >
  class B
  {
  public:
     B() {}
     ~B() {}
  };

  void main()
  {
     B<A> a;
     // Workaround: change the following line into a comment
     // and change the line after that into an executed line of code.
     a.B<A>::~B();
     // a.B<class A>::~B();
  }

Additional query words: 9.00 2.00 2.10 9.10

======================================================================
Keywords          :  kbbuglist kbfixlist
Technology        : kbVCsearch kbAudDeveloper kbCVCComp
Version           : :2.0,2.1
Issue type        : kbbug
Solution Type     : kbfix

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