[Boost-bugs] [Boost C++ Libraries] #4453: is_virtual_base_of uses common names for internal types (X and Y); naming conflicts result

Subject: [Boost-bugs] [Boost C++ Libraries] #4453: is_virtual_base_of uses common names for internal types (X and Y); naming conflicts result
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-07-19 22:41:33

#4453: is_virtual_base_of uses common names for internal types (X and Y); naming
conflicts result
------------------------------------------------+---------------------------
 Reporter:  Karl Voelker <ktvoelker@…>          |       Owner:  johnmaddock
     Type:  Bugs                                |      Status:  new        
Milestone:  To Be Determined                    |   Component:  type_traits
  Version:  Boost Development Trunk             |    Severity:  Problem    
 Keywords:                                      |  
------------------------------------------------+---------------------------
 is_virtual_base_of (and probably a lot of other type traits, I suspect)
 uses some structs internally, X and Y, which inherit from the types being
 analyzed. But if the derived type under analysis (from which Y inherits)
 has a method Y, the constructor Y::Y in the internal struct becomes a
 problem. (At least, under gcc 4.5.0 20100520 prerelease.)

 I've attached a simple demonstration of the problem. I attempted to
 compile with: g++ -c MyDerived.cpp.

 One obvious solution to this problem is to change X and Y to have bizarre
 names that are unlikely to conflict with user code. I have attached a
 patch to this effect. However, I suspect that this problem occurs in many
 other type traits.

 I'm not enough of a C++ spec expert to say whether my program ought to
 compile or not. Sorry. The real-world case from which my example was
 distilled is known to compile on MSVC++. I do not have access to MSVC++ to
 test my distillation.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4453>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.