[Bug c++/39405] New: std::shared_ptr barfs on incomplete template class that boost::shared_ptr accepts

["gcc at cohi dot at" <gcc-bugzilla at gcc dot gnu dot org>]

Can't see why this shouldn't work with std::shared_ptr; changing the type of
m_foo to std::shared_ptr<foo>, i.e. leaving out the redundant template
argument, changes nothing; only when making foo a class instead of a class
template, and removing all template arguments, does it compile.

colin@weasel:/tmp> g++-mp-4.3 -v
Using built-in specs.
Target: i386-apple-darwin9.6.0
Configured with: ../gcc-4.3.3/configure --prefix=/opt/local
--enable-languages=c,c++,objc,obj-c++,java,fortran
--libdir=/opt/local/lib/gcc43 --includedir=/opt/local/include/gcc43
--infodir=/opt/local/share/info --mandir=/opt/local/share/man
--with-local-prefix=/opt/local --with-system-zlib --disable-nls
--program-suffix=-mp-4.3 --with-gxx-include-dir=/opt/local/include/gcc43/c++/
--with-gmp=/opt/local --with-mpfr=/opt/local
Thread model: posix
gcc version 4.3.3 (GCC) 
colin@weasel:/tmp> cat t.cc
#include <memory>

template< typename T >
struct foo
{
   std::shared_ptr< foo< T > > m_foo;
};

int main()
{
   std::shared_ptr< foo< int > > t;
   return sizeof( t );
}
colin@weasel:/tmp> make t
g++-mp-4.3 -O3 -Wall -Wextra -Woverloaded-virtual -std=gnu++0x -m32
-fno-enforce-eh-specs -I/opt/local/include    t.cc   -o t
t.cc: In instantiation of 'foo<int>':
/opt/local/include/gcc43/c++/tr1_impl/type_traits:291:   instantiated from
'std::is_abstract<foo<int> >'
/opt/local/include/gcc43/c++/tr1_impl/type_traits:206:   instantiated from
'std::is_function<foo<int> >'
/opt/local/include/gcc43/c++/type_traits:127:   instantiated from
'std::add_lvalue_reference<foo<int> >'
/opt/local/include/gcc43/c++/tr1_impl/boost_shared_ptr.h:463:   instantiated
from 'std::__shared_ptr<foo<int>, _S_mutex>'
/opt/local/include/gcc43/c++/tr1_impl/boost_shared_ptr.h:822:   instantiated
from 'std::shared_ptr<foo<int> >'
t.cc:11:   instantiated from here
t.cc:6: error: 'foo<T>::m_foo' has incomplete type
/opt/local/include/gcc43/c++/tr1_impl/boost_shared_ptr.h:822: error:
declaration of 'class std::shared_ptr<foo<int> >'
make: *** [t] Error 1
colin@weasel:/tmp> cat b.cc
#include <boost/shared_ptr.hpp>

template< typename T >
struct foo
{
   boost::shared_ptr< foo< T > > m_foo;
};

int main()
{
   boost::shared_ptr< foo< int > > t;
   return sizeof( t );
}
colin@weasel:/tmp> make b
g++-mp-4.3 -O3 -Wall -Wextra -Woverloaded-virtual -std=gnu++0x -m32
-fno-enforce-eh-specs -I/opt/local/include    b.cc   -o b
colin@weasel:/tmp>


-- 
           Summary: std::shared_ptr barfs on incomplete template class that
                    boost::shared_ptr accepts
           Product: gcc
           Version: 4.3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gcc at cohi dot at
  GCC host triplet: i386-apple-darwin9.6.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39405