#include <utility>

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

class B {
public:
    B() { }
};

typedef std::pair<A*, B*> ABPair;

int main(int argc, char* argv[])
{
    B* b = 0;               // no C2440
    ABPair p2(new A(), b);

    ABPair p1(new A(), 0);  // C2440

    return 0;
}

1>ClCompile:
1>  test.cpp
1>c:program files (x86)microsoft visual studio 10.0vcincludeutility(163): error C2440: 'initializing' : cannot convert from 'int' to 'B *'
1>          Conversion from integral type to pointer type requires reinterpret_cast, C-style cast or function-style cast
1>          c:program files (x86)microsoft visual studio 10.0vcincludeutility(247) : see reference to function template instantiation 'std::_Pair_base<_Ty1,_Ty2>::_Pair_base<_Ty,int>(_Other1 &&,_Other2 &&)' being compiled
1>          with
1>          [
1>              _Ty1=A *,
1>              _Ty2=B *,
1>              _Ty=A *,
1>              _Other1=A *,
1>              _Other2=int
1>          ]
1>          c:userscharliearnolddocumentsvisual studio 2010projectstesttesttest.cpp(20) : see reference to function template instantiation 'std::pair<_Ty1,_Ty2>::pair<A*,int>(_Other1 &&,_Other2 &&)' being compiled
1>          with
1>          [
1>              _Ty1=A *,
1>              _Ty2=B *,
1>              _Other1=A *,
1>              _Other2=int
1>          ]
1>c:program files (x86)microsoft visual studio 10.0vcincludeutility(163): error C2439: 'std::_Pair_base<_Ty1,_Ty2>::second' : member could not be initialized
1>          with
1>          [
1>              _Ty1=A *,
1>              _Ty2=B *
1>          ]
1>          c:program files (x86)microsoft visual studio 10.0vcincludeutility(167) : see declaration of 'std::_Pair_base<_Ty1,_Ty2>::second'
1>          with
1>          [
1>              _Ty1=A *,
1>              _Ty2=B *
1>          ]
1>
1>Build FAILED.

#include <utility>

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

class B {
public:
    B() { }
};

typedef std::pair<A*, B*> ABPair;

ABPair make_ABPair(A* pa, B* pb)
{
    return ABPair(pa, pb);
}


int main(int argc, char* argv[])
{
    B* b = 0;               // no C2440
    ABPair p2(new A(), b);

    //ABPair p1(new A(), 0);  // C2440
    ABPair p1(make_ABPair(new A(), 0));

    return 0;
}