Code fails to compile after #397

[uyha]

Expected Behavior

Code does compile

Actual Behavior

Code doesn't compile

Steps to Reproduce the Problem

Compiling the following code

#include <queue>
#include <sml/sml.hpp>

struct Process {};

struct MainSM {
  struct s1 {};
  struct s2 {};

  auto operator()() noexcept {
    using namespace boost::sml;
    return make_transition_table(*state<s1> + event<Process> = state<s2>);
  }
};

struct ObserverSM {
  struct s1 {};
  auto operator()() noexcept {
    using namespace boost::sml;
    return make_transition_table(
        *state<s1> + event<Process> / [](sm<MainSM, process_queue<std::queue>> const &) {});
  }
};

int main() {
  using namespace boost::sml;
  auto state_machine          = sm<MainSM, process_queue<std::queue>>{};
  auto observer_state_machine = sm<ObserverSM>{state_machine};
}

Specifications

• Version: sml.hpp of #397
• Platform: Ubuntu 20.04
• Compilers: gcc-10, clang-11

[ftab]

I also got this with GCC 9.3, clang 10, and clang 11.

It has something to do with defining an sm with process_queue<std::queue> specifically since that commit (2014829), because if I take out process_queue<std::queue> from the example code, it compiles.

Log of error in GCC:

In file included from /usr/include/c++/9/deque:66,
                 from /usr/include/c++/9/queue:60,
                 from test.cpp:1:
/usr/include/c++/9/bits/stl_uninitialized.h: In instantiation of ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process>&, const boost::ext::sml::v1_1_4::back::queue_event<Process>*>; _ForwardIterator = std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, boost::ext::sml::v1_1_4::back::queue_event<Process>&, boost::ext::sml::v1_1_4::back::queue_event<Process>*>]’:
/usr/include/c++/9/bits/stl_uninitialized.h:307:37:   required from ‘_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>&) [with _InputIterator = std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process>&, const boost::ext::sml::v1_1_4::back::queue_event<Process>*>; _ForwardIterator = std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, boost::ext::sml::v1_1_4::back::queue_event<Process>&, boost::ext::sml::v1_1_4::back::queue_event<Process>*>; _Tp = boost::ext::sml::v1_1_4::back::queue_event<Process>]’
/usr/include/c++/9/bits/stl_deque.h:977:36:   required from ‘std::deque<_Tp, _Alloc>::deque(const std::deque<_Tp, _Alloc>&) [with _Tp = boost::ext::sml::v1_1_4::back::queue_event<Process>; _Alloc = std::allocator<boost::ext::sml::v1_1_4::back::queue_event<Process> >]’
/usr/include/c++/9/bits/stl_queue.h:96:11:   required from ‘boost::ext::sml::v1_1_4::back::sm< <template-parameter-1-1> >::sm(TDeps&&) [with TDeps = const boost::ext::sml::v1_1_4::back::sm<boost::ext::sml::v1_1_4::back::sm_policy<MainSM, boost::ext::sml::v1_1_4::back::policies::process_queue<std::queue> > >; typename boost::ext::sml::v1_1_4::aux::enable_if<(! boost::ext::sml::v1_1_4::aux::is_same<typename boost::ext::sml::v1_1_4::aux::remove_reference<TDeps>::type, boost::ext::sml::v1_1_4::back::sm< <template-parameter-1-1> > >::value), int>::type <anonymous> = 0; TSM = boost::ext::sml::v1_1_4::back::sm_policy<MainSM, boost::ext::sml::v1_1_4::back::policies::process_queue<std::queue> >]’
boost/sml.hpp:357:8:   required from here
/usr/include/c++/9/bits/stl_uninitialized.h:127:72: error: static assertion failed: result type must be constructible from value type of input range
  127 |       static_assert(is_constructible<_ValueType2, decltype(*__first)>::value,
      |                                                                        ^~~~~

Log of error in clang:

In file included from test.cpp:1:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/queue:60:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/deque:66:
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_uninitialized.h:127:7: error: static_assert failed due to requirement 'is_constructible<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process> &>::value' "result type must be constructible from value type of input range"
      static_assert(is_constructible<_ValueType2, decltype(*__first)>::value,
      ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_uninitialized.h:307:19: note: in instantiation of function template specialization 'std::uninitialized_copy<std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process> &, const boost::ext::sml::v1_1_4::back::queue_event<Process> *>, std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, boost::ext::sml::v1_1_4::back::queue_event<Process> &, boost::ext::sml::v1_1_4::back::queue_event<Process> *> >' requested here
    { return std::uninitialized_copy(__first, __last, __result); }
                  ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_deque.h:977:14: note: in instantiation of function template specialization 'std::__uninitialized_copy_a<std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process> &, const boost::ext::sml::v1_1_4::back::queue_event<Process> *>, std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, boost::ext::sml::v1_1_4::back::queue_event<Process> &, boost::ext::sml::v1_1_4::back::queue_event<Process> *>, boost::ext::sml::v1_1_4::back::queue_event<Process> >' requested here
      { std::__uninitialized_copy_a(__x.begin(), __x.end(),
             ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_queue.h:96:11: note: in instantiation of member function 'std::deque<boost::ext::sml::v1_1_4::back::queue_event<Process>, std::allocator<boost::ext::sml::v1_1_4::back::queue_event<Process> > >::deque' requested here
    class queue
          ^
./boost/sml.hpp:1715:75: note: in instantiation of function template specialization 'boost::ext::sml::v1_1_4::aux::pool<boost::ext::sml::v1_1_4::back::sm_impl<boost::ext::sml::v1_1_4::back::sm_policy<ObserverSM> > >::pool<boost::ext::sml::v1_1_4::back::sm<boost::ext::sml::v1_1_4::back::sm_policy<MainSM, boost::ext::sml::v1_1_4::back::policies::process_queue<queue> > > &>' requested here
  explicit sm(TDeps &&deps) : deps_{aux::init{}, aux::pool<TDeps>{deps}}, sub_sms_{aux::pool<TDeps>{deps}} {
                                                                          ^
test.cpp:28:33: note: in instantiation of function template specialization 'boost::ext::sml::v1_1_4::back::sm<boost::ext::sml::v1_1_4::back::sm_policy<ObserverSM> >::sm<boost::ext::sml::v1_1_4::back::sm<boost::ext::sml::v1_1_4::back::sm_policy<MainSM, boost::ext::sml::v1_1_4::back::policies::process_queue<queue> > > &, 0>' requested here
  auto observer_state_machine = sm<ObserverSM>{state_machine};
                                ^
In file included from test.cpp:1:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/queue:60:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/deque:65:
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_construct.h:75:38: error: call to deleted constructor of 'boost::ext::sml::v1_1_4::back::queue_event<Process>'
    { ::new(static_cast<void*>(__p)) _T1(std::forward<_Args>(__args)...); }
                                     ^   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_uninitialized.h:83:8: note: in instantiation of function template specialization 'std::_Construct<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process> &>' requested here
                std::_Construct(std::__addressof(*__cur), *__first);
                     ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_uninitialized.h:140:2: note: in instantiation of function template specialization 'std::__uninitialized_copy<false>::__uninit_copy<std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process> &, const boost::ext::sml::v1_1_4::back::queue_event<Process> *>, std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, boost::ext::sml::v1_1_4::back::queue_event<Process> &, boost::ext::sml::v1_1_4::back::queue_event<Process> *> >' requested here
        __uninit_copy(__first, __last, __result);
        ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_uninitialized.h:307:19: note: in instantiation of function template specialization 'std::uninitialized_copy<std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process> &, const boost::ext::sml::v1_1_4::back::queue_event<Process> *>, std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, boost::ext::sml::v1_1_4::back::queue_event<Process> &, boost::ext::sml::v1_1_4::back::queue_event<Process> *> >' requested here
    { return std::uninitialized_copy(__first, __last, __result); }
                  ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_deque.h:977:14: note: in instantiation of function template specialization 'std::__uninitialized_copy_a<std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, const boost::ext::sml::v1_1_4::back::queue_event<Process> &, const boost::ext::sml::v1_1_4::back::queue_event<Process> *>, std::_Deque_iterator<boost::ext::sml::v1_1_4::back::queue_event<Process>, boost::ext::sml::v1_1_4::back::queue_event<Process> &, boost::ext::sml::v1_1_4::back::queue_event<Process> *>, boost::ext::sml::v1_1_4::back::queue_event<Process> >' requested here
      { std::__uninitialized_copy_a(__x.begin(), __x.end(),
             ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_queue.h:96:11: note: in instantiation of member function 'std::deque<boost::ext::sml::v1_1_4::back::queue_event<Process>, std::allocator<boost::ext::sml::v1_1_4::back::queue_event<Process> > >::deque' requested here
    class queue
          ^
./boost/sml.hpp:1715:75: note: in instantiation of function template specialization 'boost::ext::sml::v1_1_4::aux::pool<boost::ext::sml::v1_1_4::back::sm_impl<boost::ext::sml::v1_1_4::back::sm_policy<ObserverSM> > >::pool<boost::ext::sml::v1_1_4::back::sm<boost::ext::sml::v1_1_4::back::sm_policy<MainSM, boost::ext::sml::v1_1_4::back::policies::process_queue<queue> > > &>' requested here
  explicit sm(TDeps &&deps) : deps_{aux::init{}, aux::pool<TDeps>{deps}}, sub_sms_{aux::pool<TDeps>{deps}} {
                                                                          ^
test.cpp:28:33: note: in instantiation of function template specialization 'boost::ext::sml::v1_1_4::back::sm<boost::ext::sml::v1_1_4::back::sm_policy<ObserverSM> >::sm<boost::ext::sml::v1_1_4::back::sm<boost::ext::sml::v1_1_4::back::sm_policy<MainSM, boost::ext::sml::v1_1_4::back::policies::process_queue<queue> > > &, 0>' requested here
  auto observer_state_machine = sm<ObserverSM>{state_machine};
                                ^
./boost/sml.hpp:636:3: note: 'queue_event' has been explicitly marked deleted here
  queue_event(const queue_event &) = delete;
  ^
2 errors generated.