Re: [boost] [test]enable_if, etc. : was : ...multiprecision types ... for unit tests?

Subject: Re: [boost] [test]enable_if, etc. : was : ...multiprecision types ... for unit tests?
From: Gennadiy Rozental (rogeeff_at_[hidden])
Date: 2013-06-12 22:29:21

Christopher Kormanyos <e_float <at> yahoo.com> writes:

> * OK for GCC 4.7.2
> * Errors for VC10 (ambiguous symbols), AKA VisualStudio 2010
> * Errors for VC11 (ambiguous symbols), AKA VisualStudio 2012

Sorry. I've misinterpreted MSVC output. I do see the error now. And... this 
is really weird one. I did not see something like this in a long time. What 
it comes to can be illustrated in this example:

#include <boost/multiprecision/cpp_dec_float.hpp>

namespace boost {

struct A{};

namespace inner1 {
struct enable_if {};
} // inner 

namespace inner2 {
using namespace ::boost::inner1;

template<typename T>
void    f1( A& )    {}

void    f2()
{ 
    f1<int>( A() ); // <=== !!!!!! Offending line
}

} // inner2
} // boost

void foo()
{
  typedef 
boost::multiprecision::number<boost::multiprecision::cpp_dec_float<50>,
                                        boost::multiprecision::et_off> 
mp_type;

  const mp_type test_value = mp_type(12) / 7;
}

I'm sure it can be simplified further by removing specifics of 
multiprecision library. And the offending line is ... the template 
instantiation, in unrelated namespace HAS NOTHING TO DO with enable_if at 
all. 

Good job MS - I am still trying to figure out how you manage to achieve this 
"result".

Any hints are welcome.

Gennadiy