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.