[Boost-users] Fwd: Boost.Range: 'Use of deleted function' GCC error when using lambdas

Subject: [Boost-users] Fwd: Boost.Range: 'Use of deleted function' GCC error when using lambdas
From: Remko Tronçon (remko_at_[hidden])
Date: 2016-09-01 11:48:03

Hi,

I have the following piece of code:

    std::vector<std::string> list1;
    std::vector<std::string> list2;
    push_back(list2, list1
        | transformed([](const auto& w) { return w; })
        | sliced(0, 1));

This compiles fine with CLang, but with GCC I get the error:

    /usr/include/boost/optional/optional.hpp:546:64: error: use of deleted
function 'main(int, const char**)::<lambda(const auto:1&)>& main(int, const
char**)::<lambda(const auto:1&)>::operator=(const main(int, const
char**)::<lambda(const auto:1&)>&)'
     void assign_value ( rval_reference_type val ) { get_impl() =
static_cast<rval_reference_type>(val); }

 ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   main.cpp:46:19: note: a lambda closure type has a deleted copy
assignment operator
    | transformed([](const auto& w) { return w; })

When I replace the lambda by a regular function, the code compiles; when I
don't use 'sliced' (but pipe it to e.g. 'transformed' instead), the code
also compiles.

Is there a way to make this code compile with a lambda?

thanks!
Remko

PS: I'm using GCC 6.2.0 with Boost 1.61.