CODEWITHSUNDEEP
c++c++11visual-studio-2010compiler-bug
Simon
Simon

Reputation: 1504

Compiler Error in Function Template with VS2010 SP1

Why i get the marked compiler error (C2899)? I tried with VS2010 SP1.

#include <list>
#include <vector>
#include <algorithm>

template <typename source_container_type, typename target_container_type>
void copy_all(const source_container_type& source, target_container_type& target)
 {
    std::for_each(begin(source), end(source), [&] (const typename source_container_type::value_type& element)
    {
        // error C2899: typename cannot be used outside a template declaration
        // error C2653: 'target_container_type' : is not a class or namespace name
         target.push_back(typename target_container_type::value_type(element));
    });
}

int main()
{
    std::vector<int> a;
    a.push_back(23);
    a.push_back(24);
    a.push_back(25);

    std::list<int> b;
    copy_all(a, b);
}

Kind regards
Simon

PS: I know i could use std::copy(..) with std::back_inserter(..) - but that's not the point.

EDIT

The question was answered in a comment by perreal: http://connect.microsoft.com/VisualStudio/feedback/details/694857/bug-in-lambda-expressions

EDIT

Please note that i'm not interested in workarounds. I want to know whether the code above should compile or not.

Upvotes: 3

Views: 461

Answers (4)

Jagannath
Jagannath

Reputation: 4025

Sorry don't have VS2010 available. Try moving the typedef outside of lambda. Works on g++.

#include <list> 
#include <vector> 
#include <algorithm> 

template <typename source_container_type, typename target_container_type> 
void copy_all(const source_container_type& source, target_container_type& target) 
 {
    typedef typename target_container_type::value_type TargetType; /// Code change here.

    std::for_each(source.begin(), source.end(), [&] (const typename source_container_type::value_type& element) 
    { 
         target.push_back(TargetType(element)); 
    }); 
} 

int main() 
{ 
    std::vector<int> a; 
    a.push_back(23); 
    a.push_back(24); 
    a.push_back(25); 

    std::list<int> b; 
    copy_all(a, b); 
}

Upvotes: 1

Ajay
Ajay

Reputation: 18431

Since you are using C++0x/11, you can use:

target.push_back( (decltype(element))(element));

Upvotes: 0

bitmask
bitmask

Reputation: 34636

Your line is valid: http://ideone.com/qAF7r

Even the ancient g++ 4.3 compiles it. So it's probably a bug in your MS compiler.

Upvotes: 1

Alastair Taylor
Alastair Taylor

Reputation: 425

I may be misunderstanding what you are trying to achieve but shouldn't the line in question simply be:

target.push_back(element);

Upvotes: 0

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