Hello, I get errors related to lambdas not being default-constructible or copy-assignable when using a lambda as a predicate with certain adaptors (e.g. filtered) and certain algorithms (e.g. min_element). The following code illustrates the problem: #include <boost/range/algorithm/min_element.hpp> #include <boost/range/adaptor/filtered.hpp> int main() { int a[] = {1, 2, 3}; auto is_odd = [](int i){ return i % 2 == 1; }; boost::min_element(a | boost::adaptors::filtered(is_odd)); } The errors are shown below. Is there a workaround for this? Thanks, Nate. Errors: In file included from algorithm:63:0, from /usr/lib/boost/boost/iterator/iterator_concepts.hpp:29, from /usr/lib/boost/boost/range/concepts.hpp:20, from /usr/lib/boost/boost/range/algorithm/min_element.hpp:15, from test.cpp:1: stl_algo.h: In function 'boost::filter_iterator<main()::<lambda(int)>, int *> min_element( boost::filter_iterator<main()::<lambda(int)>, int *> , boost::filter_iterator<main()::<lambda(int)>, int *> )': /usr/lib/boost/boost/range/algorithm/min_element.hpp:44:63: instantiated from 'boost::range_iterator<const T>::ame boost ::range_iterator<const T>::type = boost::filter_iterator< main()::<lambda(int)>, int * > boost::range::min_element( const boost::range_detail::filtered_range< main()::<lambda(int)>, int [3] > & )' test.cpp:8:61: instantiated from here stl_algo.h:6109:4: error: use of deleted function 'boost::filter_iterator< main()::<lambda(int)>, int * > & boost::filter_iterator<main()::<lambda(int)>, int *>::operator=( const boost::filter_iterator<main()::<lambda(int)>, int *> & )' In file included from /usr/lib/boost/boost/range/adaptor/filtered.hpp :16:0, from test.cpp:2: /usr/lib/boost/boost/iterator/filter_iterator.hpp:44:9: error: 'boost ::filter_iterator<main()::<lambda(int)>, int *> & boost::filter_iterator< main()::<lambda(int)>, int * >::operator=( const boost::filter_iterator<main()::<lambda(int)>, int *> & )' is implicitly deleted because the default definition would be ill- formed: /usr/lib/boost/boost/iterator/filter_iterator.hpp:44:9: error: use of deleted function 'main()::<lambda(int)> & main()::<lambda(int)>::operator=( const main()::<lambda(int)> & )' test.cpp:7:20: error: a lambda closure type has a deleted copy assignment operator In file included from /usr/lib/boost/boost/range/adaptor/filtered.hpp :16:0, from test.cpp:2: /usr/lib/boost/boost/iterator/filter_iterator.hpp: In constructor 'boost::filter_iterator<main()::<lambda(int)>, int *>::filter_iterator()': /usr/lib/boost/boost/concept_check.hpp:133:10: instantiated from 'boost::DefaultConstructible< boost::filter_iterator<main()::<lambda(int)>, int *> >::~DefaultConstructible()' /usr/lib/boost/boost/concept/usage.hpp:22:29: instantiated from 'boost::concepts::usage_requirements< boost::DefaultConstructible< boost::filter_iterator<main()::<lambda(int)>, int *> > >::~usage_requirements()' /usr/lib/boost/boost/concept/detail/general.hpp:38:28: instantiated from 'static void boost::concepts::requirement< boost::concepts::failed ************ boost::concepts ::usage_requirements< boost::DefaultConstructible< boost::filter_iterator<main()::<lambda(int)>, int *> > >::************ >::failed()' /usr/lib/boost/boost/concept_check.hpp:132:1: instantiated from 'boost::DefaultConstructible< boost::filter_iterator<main()::<lambda(int)>, int *> >' /usr/lib/boost/boost/range/concepts.hpp:169:16: instantiated from 'boost::range_detail::ForwardIteratorConcept< boost::filter_iterator<main()::<lambda(int)>, int *> >' /usr/lib/boost/boost/concept/detail/has_constraints.hpp:42:5: [ skipping 5 instantiation contexts ] /usr/lib/boost/boost/concept/detail/has_constraints.hpp:42:5: instantiated from 'const bool boost::concepts::not_satisfied< boost::ForwardRangeConcept< const boost::range_detail::filtered_range< main()::<lambda(int)>, int [3] > > >::value' /usr/lib/boost/boost/concept/detail/has_constraints.hpp:45:31: instantiated from 'boost::concepts::not_satisfied< boost::ForwardRangeConcept< const boost::range_detail::filtered_range< main()::<lambda(int)>, int [3] > > >' /usr/lib/boost/boost/mpl/if.hpp:67:11: instantiated from 'boost::mpl ::if_< boost::concepts::not_satisfied< boost::ForwardRangeConcept< const boost::range_detail::filtered_range< main()::<lambda(int)>, int [3] > > >, boost::concepts::constraint< boost::ForwardRangeConcept< const boost::range_detail::filtered_range< main()::<lambda(int)>, int [3] > > >, boost::concepts::requirement< boost::concepts::failed ************ boost::ForwardRangeConcept< const boost::range_detail::filtered_range< main()::<lambda(int)>, int [3] > >::************ > >' /usr/lib/boost/boost/concept/detail/general.hpp:50:8: instantiated from 'boost::concepts::requirement_< void (*)( boost::ForwardRangeConcept< const boost::range_detail::filtered_range< main()::<lambda(int)>, int [3] > > ) >' /usr/lib/boost/boost/range/algorithm/min_element.hpp:43:1: instantiated from 'boost::range_iterator<const T>::ame boost ::range_iterator<const T>::type = boost::filter_iterator< main()::<lambda(int)>, int * > boost::range::min_element( const boost::range_detail::filtered_range< main()::<lambda(int)>, int [3] > & )' test.cpp:8:61: instantiated from here /usr/lib/boost/boost/iterator/filter_iterator.hpp:54:25: error: use of deleted function 'main()::<lambda(int)>::<lambda>()' test.cpp:7:20: error: a lambda closure type has a deleted default constructor