id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
6811	Default argument of type multi_array fails under MSVC 2010 SP1	Bruce Merry <bmerry@…>	Ronald Garcia	"When I write a function with the signature

{{{
typedef boost::multi_array<int, 3> T;
void bar(const T &value = T())
}}}
and compile it with MSVC 2010 SP1 I get the following error messages
{{{
E:\postdoc\boost-bug>cl /EHsc /Ie:/postdoc/tools/boost_1_49_0 mar-bug.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 16.00.40219.01 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

mar-bug.cpp
e:/postdoc/tools/boost_1_49_0\boost/multi_array/multi_array_ref.hpp(73) : error
C3855: 'boost::const_multi_array_ref': template parameter 'NumDims' is incompati
ble with the declaration
        e:/postdoc/tools/boost_1_49_0\boost/multi_array/multi_array_ref.hpp(417)
 : see reference to class template instantiation 'boost::const_multi_array_ref<T
,NumDims,TPtr>' being compiled
        with
        [
            T=int,
            NumDims=0x03,
            TPtr=int *
        ]
        e:/postdoc/tools/boost_1_49_0\boost/multi_array.hpp(113) : see reference
 to class template instantiation 'boost::multi_array_ref<T,NumDims>' being compi
led
        with
        [
            T=int,
            NumDims=0x03
        ]
        mar-bug.cpp(5) : see reference to class template instantiation 'boost::m
ulti_array<T,NumDims>' being compiled
        with
        [
            T=int,
            NumDims=0x03
        ]
}}}

The offending piece of code appears to be in `boost/multi_array/multi_array_ref.hpp`:

{{{
 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
   // make const_multi_array_ref a friend of itself
   template <typename,std::size_t,typename>
   friend class const_multi_array_ref;
#endif
}}}

If I give the template arguments names then the compiler is happy (I'll attach a patch).

I have no idea what is special about using the type as a default argument - I tried to reproduce it using simpler steps (copy constructor, default constructor, assigning a temporary to a const ref inside a function) with no luck."	Bugs	new	To Be Determined	multi_array	Boost 1.49.0	Problem