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Boost.org concept_check module

Home Page: http://boost.org/libs/concept_check

License: Boost Software License 1.0

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concept_check's Introduction

ConceptCheck, part of collection of the Boost C++ Libraries, allows one to add explicit statement and checking of concepts in the style of the proposed C++ language extension.

License

Distributed under the Boost Software License, Version 1.0.

Properties

C++03
Header-only

Build Status

Branch	GHA CI	Appveyor	Coverity Scan	codecov.io	Deps	Docs	Tests
`master`
`develop`

Directories

Name	Purpose
`doc`	documentation
`include`	headers
`test`	unit tests

More information

Ask questions
Report bugs: Be sure to mention Boost version, platform and compiler you're using. A small compilable code sample to reproduce the problem is always good as well.
Submit your patches as pull requests against develop branch. Note that by submitting patches you agree to license your modifications under the Boost Software License, Version 1.0.
Discussions about the library are held on the Boost developers mailing list. Be sure to read the discussion policy before posting and add the [concept_check] tag at the beginning of the subject line.

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concept_check's Issues

variable 'a' is uninitialized when passed as a const reference argument here warning when compiling with clang-cl.exe

Hi!

In file boost/concept_check.hpp:

boost/concept_check.hpp(139,38): error : variable 'a' is uninitialized when passed as a const reference argument here [-Werror,-Wuninitialized-const-reference]

CodeWarrior: Illegal template arguments

Boost Version: 1.79.0
Platform: Baremetal PowerPC
Compiler: CodeWarrior
Using C++03.

The failed template thingy is causing compilation to fail with CodeWarrior with the error illegal template arguments on this line and this line. This occurs when trying to use Boost circular_buffer. I'm guessing it's due to the asterisks?

GCC 11.2.0 [-Werror=nonnull]

My current C++ code compiles without any warnings using GCC 7.3 or 10.2.

Now, I switch to GCC 11.2.0 and the same code gives me a set of this message below:

error: 'this' pointer is null [-Werror=nonnull]

In file included from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/concept/assert.hpp:35,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/concept_check.hpp:20,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/range/concepts.hpp:19,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/range/size_type.hpp:20,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/range/size.hpp:21,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/range/functions.hpp:20,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/range/iterator_range_core.hpp:38,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/range/iterator_range.hpp:13,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/range/as_literal.hpp:22,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/algorithm/string/trim.hpp:19,
                 from C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/algorithm/string.hpp:19,
                 from C:\dev\evo-pos\src\evopos\core\remote_transactions\remote_transactions_screens.cpp:18:
C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::constraint<Model>::failed() [with Model = boost::algorithm::FinderConcept<boost::algorithm::detail::token_finderF<boost::algorithm::detail::is_any_ofF<char> >, __gnu_cxx::__normal_iterator<char*, std::__cxx11::basic_string<char> > >]':
C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/algorithm/string/iter_find.hpp:77:13:   required from 'SequenceSequenceT& boost::algorithm::iter_split(SequenceSequenceT&, RangeT&, FinderT) [with SequenceSequenceT = std::vector<std::__cxx11::basic_string<char> >; RangeT = std::__cxx11::basic_string<char>; FinderT = boost::algorithm::detail::token_finderF<boost::algorithm::detail::is_any_ofF<char> >]'
C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/algorithm/string/split.hpp:146:50:   required from 'SequenceSequenceT& boost::algorithm::split(SequenceSequenceT&, RangeT&, PredicateT, boost::algorithm::token_compress_mode_type) [with SequenceSequenceT = std::vector<std::__cxx11::basic_string<char> >; RangeT = std::__cxx11::basic_string<char>; PredicateT = boost::algorithm::detail::is_any_ofF<char>]'
C:\dev\evo-pos\src\evopos\core\remote_transactions\remote_transactions_screens.cpp:261:17:   required from here
C:\dev\evo-pos\submodules\evo-tef-client\submodules\cpp-third-party-libs\windows\amd64\boost-1.68.0\include/boost/concept/detail/general.hpp:47:52: error: 'this' pointer is null [-Werror=nonnull]
   47 |     static void failed() { ((Model*)0)->constraints(); }
      |                            ~~~~~~~~~~~~~~~~~~~~~~~~^~

My system:

Windows 11 x64
Compiler: G++ 11.2.0 (MSYS2)
Boost: 1.68.0
C++ standard flag: -std=c++0x

Warning C4834 occurs in the line 355 of concept_check.hpp

I'm a member of Mrcrosoft VCPKG team, when we test vcpkg with an internal version of VS, pagmo2 installation failed with below error:
D:\installed\x64-windows\include\boost/concept_check.hpp(355): error C2220: the following warning is treated as an error
D:\installed\x64-windows\include\boost/concept_check.hpp(355): warning C4834: discarding return value of function with 'nodiscard' attribute

This warning caused by the change: microsoft/STL#1474 , [nodiscard] was added before some operator() function and the change of STL is by design.

Since the warning was reported in the concept_check.hpp file, I think we can make some modifications on boost-concept-check to fix this issue, such as comment the line 355. I'm not sure if this will change the function function, please help to confirm.
Thank you!

Visual Studio 2022 17.5 with Boost libraries multiple errors in concept_check.hpp

After VS 2022 update from 17.4.xx to 17.5 I started to get multiple errors detected in concept_check.hpp module.

While my whole code is compiling and build properly, the Intellisense of VS2022 stops working due to many errors detected in editor.

The issue is confirmed on Microsoft VS 2022 community by few users however not solution so far and not sure where the problems is.

Problem is not visible in VS2022 17.4.xx and ealier.

The problem is confirmed in latest Boost 1.81 and ealier 1.78.

Test stl_concept_covering.cpp failed in clang on Windows

When running latest stl_concept_covering.cpp in clang on Windows, I got the following error message.

In file included from stl_concept_covering.cpp:6:
vs2019/VC/Tools/MSVC/14.20.27508/include\algorithm(2467,9): error: cannot decrement value of type 'boost::mutable_forward_iterator_archetype<boost::sgi_assignable_archetype<boost::convertible_to_archetype<boost::null_archetype<int>, boost::default_archetype_base> > >'
        --_Last;
        ^ ~~~~~
vs2019/VC/Tools/MSVC/14.20.27508/include\algorithm(2488,27): note: in instantiation of function template specialization 'std::_Stable_partition_unchecked<boost::mutable_forward_iterator_archetype<boost::sgi_assignable_archetype<boost::convertible_to_archetype<boost::null_archetype<int>, boost::default_archetype_base> > >, boost::unary_predicate_archetype<boost::null_archetyp
e<int> > >' requested here
    _Seek_wrapped(_First, _Stable_partition_unchecked(_Get_unwrapped(_First), _Get_unwrapped(_Last), _Pass_fn(_Pred)));
                          ^
stl_concept_covering.cpp(558,15): note: in instantiation of function template specialization 'std::stable_partition<boost::mutable_forward_iterator_archetype<boost::sgi_assignable_archetype<boost::convertible_to_archetype<boost::null_archetype<int>, boost::default_archetype_base> > >, boost::unary_predicate_archetype<boost::null_archetype<int> > >' requested here
    fi = std::stable_partition(fi, fi, pred);
              ^

I noticed these few lines would not run in msvc.

ksh-3.2$ sed -n "552,561p" stl_concept_covering.cpp
#ifndef BOOST_MSVC
  {
    // fails on MSVC
    typedef null_archetype<> PredArg;
    typedef sgi_assignable_archetype<convertible_to_archetype<PredArg> > FT;
    mutable_forward_iterator_archetype<FT> fi;
    unary_predicate_archetype<PredArg> pred(dummy_cons);
    fi = std::stable_partition(fi, fi, pred);
  }
#endif

If this test was forced to run in msvc(cl), and there would be an similar error in line 558 too. The error message of cl looks like below.

C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.15.26726\include\algorithm(2888): error C2675: unary '--': '_BidIt' does not define this operator or a conversion to a type acceptable to the predefined operator
        with
        [
            _BidIt=boost::mutable_forward_iterator_archetype<FT>
        ]
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.15.26726\include\algorithm(2914): note: see reference to function template instantiation '_BidIt std::_Stable_partition_unchecked<_Iter,_Fn>(_BidIt,_BidIt,_Pr)' being compiled
        with
        [
            _BidIt=boost::mutable_forward_iterator_archetype<FT>,
            _Iter=boost::mutable_forward_iterator_archetype<FT>,
            _Fn=boost::unary_predicate_archetype<T>,
            _Pr=boost::unary_predicate_archetype<T>
        ]
stl_concept_covering.cpp(558): note: see reference to function template instantiation '_BidIt std::stable_partition<boost::mutable_forward_iterator_archetype<FT>,boost::unary_predicate_archetype<T>>(_BidIt,_BidIt,_Pr)' being compiled
        with
        [
            _BidIt=boost::mutable_forward_iterator_archetype<FT>,
            _Pr=boost::unary_predicate_archetype<T>
        ]

So, if this is an known issue on Windows and cannot be fixed,

should the macro judgement in this code segment be changed to avoid running in some other compilers on Windows, like clang-cl?
is it possible to make some changes in this code to avoid errors on Windows? Still no clear why it can run on Linux but not on Windows.
Thanks a lot!

Tons of errors in concept_check.hpp using VS 2022

There are about a million (slight exaggeration) errors in concept_check.hpp, such as:

identifier "BOOST_PP_IIF_BOOST_PP_BOOL_" is undefined concept_check.hpp:70
type name is not allowed concept_check.hpp:80
too few arguments for class template "boost::Integer" concept_check.hpp:80

These are repeated for basically every usage of the BOOST_concept macro in concept_check.hpp. The line number obviously changes.

Modular Boost C++ Libraries Request

We are in the process of making B2 build changes to all of the B2 build files
to support "modular" consumption of the Boost Libraries by users. See this list
post for some details: https://lists.boost.org/Archives/boost/2024/01/255704.php

The process requires making a variety of changes to make each Boost library
independent of the super-project structure. But the changes do not remove the
super-project structure or the comprehensive Boost release. The changes make
solely make it possible, optionally, for users, like package manages, to easily
consume libraries individually.

Generally the changes include:

Adding a libroot/build.jam.
Porting any functionality from libroot/jamfile to libroot/build.jam.
Moving boost-install declaration from libroot/build/jamfile is applicable.
Adjusting other B2 build files in the library, like test/jamfile, as needed.
Possible changes to C++ source files to remove includes relative to the
super-project boostroot location.

Some examples of such changes:

We are asking how you would like us to handle the changes. We would prefer if
you allow the owners of the Boost.org GitHub project to make changes to B2
build files, as needed, to accomplish the changes. But understand
that you may want to manage the proposed changes yourself.

We previously sent emails to all known maintainers to fill out a form with their
preference. We are contacting you in this issue as we have not gotten a response
to that email. You can see the ongoing responses for that form and the responses
to these issues here https://github.com/users/grafikrobot/projects/1/views/6

We are now asking if you can reply directly to this issue to indicate your
preference of handling the changes. Please supply a response to this question
and close the issue (so that we can verify you are a maintainer).

How would you like the build changes to be processed?

Pull request, reviewed and merged by a BOOSTORG OWNER.
Pull request, reviewed and merged by YOU.
Other. (please specify details in the reply)

Also please indicate any special instructions you want us to consider. Or other
information you want us to be aware of.

Thanks you, René

warning: 'this' pointer null [-Wnonnull] (enabled with -Wall)

GCC trunk has a new diagnostic https://wandbox.org/permlink/5YWcuQ9L3ezmXANI

In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::Assignable<const char*> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:145:5:   required from 'struct boost::Assignable<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIteratorConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ReadableIteratorConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ReadableIteratorConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:30:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::Assignable<const char*>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::CopyConstructible<const char*> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:167:5:   required from 'struct boost::CopyConstructible<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIteratorConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ReadableIteratorConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ReadableIteratorConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:30:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::CopyConstructible<const char*>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost_concepts::ReadableIterator<const char*> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:48:7:   required from 'struct boost_concepts::ReadableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIteratorConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ReadableIteratorConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ReadableIteratorConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:30:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost_concepts::ReadableIterator<const char*>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost_concepts::ReadableIteratorConcept<const char*>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:30:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/aux_/integral_wrapper.hpp:22,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/int.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/lambda_fwd.hpp:23,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/aux_/na_spec.hpp:18,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/identity.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/context.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parser.hpp:18,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:17: note: in a call to non-static member function 'boost_concepts::ReadableIteratorConcept<const char*>::~ReadableIteratorConcept()'
   40 |   BOOST_concept(ReadableIterator,(Iterator))
      |                 ^~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/preprocessor/cat.hpp:29:34: note: in definition of macro 'BOOST_PP_CAT_I'
   29 | #    define BOOST_PP_CAT_I(a, b) a ## b
      |                                  ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/concept_def.hpp:23:12: note: in expansion of macro 'BOOST_PP_CAT'
   23 |     struct BOOST_PP_CAT(name,Concept)                                           \
      |            ^~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3: note: in expansion of macro 'BOOST_concept'
   40 |   BOOST_concept(ReadableIterator,(Iterator))
      |   ^~~~~~~~~~~~~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5:   required from 'struct boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:114:7:   [ skipping 5 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:114:7:   required from 'struct boost_concepts::IncrementableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:129:3:   required from 'struct boost_concepts::SinglePassIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversalConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ForwardTraversalConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::Convertible<X, Y>::~Convertible() [with X = boost::iterators::random_access_traversal_tag; Y = boost::iterators::incrementable_traversal_tag]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  208 |     BOOST_CONCEPT_USAGE(Convertible) {
      |     ^~~~~~~~~~~~~~~~~~~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost_concepts::IncrementableIterator<const char*> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:120:7:   required from 'struct boost_concepts::IncrementableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:129:3:   required from 'struct boost_concepts::SinglePassIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversalConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ForwardTraversalConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost_concepts::IncrementableIterator<const char*>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::EqualityComparable<const char*> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:233:5:   required from 'struct boost::EqualityComparable<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:129:3:   required from 'struct boost_concepts::SinglePassIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversalConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ForwardTraversalConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::EqualityComparable<const char*>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5:   required from 'struct boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:134:7:   [ skipping 4 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:134:7:   required from 'struct boost_concepts::SinglePassIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversalConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ForwardTraversalConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::Convertible<X, Y>::~Convertible() [with X = boost::iterators::random_access_traversal_tag; Y = boost::iterators::single_pass_traversal_tag]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  208 |     BOOST_CONCEPT_USAGE(Convertible) {
      |     ^~~~~~~~~~~~~~~~~~~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::DefaultConstructible<const char*> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:137:5:   required from 'struct boost::DefaultConstructible<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversalConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ForwardTraversalConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::DefaultConstructible<const char*>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag> >]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5:   required from 'struct boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:150:7:   [ skipping 3 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:5: note: in a call to non-static member function 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag>]'
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |     ^
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:150:7:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversalConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ForwardTraversalConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::Convertible<X, Y>::~Convertible() [with X = boost::iterators::random_access_traversal_tag; Y = boost::iterators::forward_traversal_tag]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  208 |     BOOST_CONCEPT_USAGE(Convertible) {
      |     ^~~~~~~~~~~~~~~~~~~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/assert.hpp:35,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp: In instantiation of 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost_concepts::ForwardTraversalConcept<const char*>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47: warning: 'this' pointer null [-Wnonnull]
   39 |     static void failed() { ((Model*)0)->~Model(); }
      |                            ~~~~~~~~~~~~~~~~~~~^~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/aux_/integral_wrapper.hpp:22,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/int.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/lambda_fwd.hpp:23,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/aux_/na_spec.hpp:18,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/mpl/identity.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/context.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parser.hpp:18,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:17: note: in a call to non-static member function 'boost_concepts::ForwardTraversalConcept<const char*>::~ForwardTraversalConcept()'
  141 |   BOOST_concept(ForwardTraversal,(Iterator))
      |                 ^~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/preprocessor/cat.hpp:29:34: note: in definition of macro 'BOOST_PP_CAT_I'
   29 | #    define BOOST_PP_CAT_I(a, b) a ## b
      |                                  ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/concept_def.hpp:23:12: note: in expansion of macro 'BOOST_PP_CAT'
   23 |     struct BOOST_PP_CAT(name,Concept)                                           \
      |            ^~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3: note: in expansion of macro 'BOOST_concept'
  141 |   BOOST_concept(ForwardTraversal,(Iterator))
      |   ^~~~~~~~~~~~~
In file included from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:31,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/concepts.hpp:19,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size_type.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/size.hpp:21,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/functions.hpp:20,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range_core.hpp:38,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/range/iterator_range.hpp:13,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/is_range.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/attribute_category.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/support/traits/move_to.hpp:12,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary/any_parser.hpp:17,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/auxiliary.hpp:11,
                 from /opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3.hpp:14,
                 from prog.cc:2:
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::Assignable<const char*>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::Assignable<const char*> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:145:5:   required from 'struct boost::Assignable<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIteratorConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ReadableIteratorConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ReadableIteratorConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:30:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::Assignable<TT>::~Assignable() [with TT = const char*]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:145:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  145 |     BOOST_CONCEPT_USAGE(Assignable) {
      |     ^~~~~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::CopyConstructible<const char*>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::CopyConstructible<const char*> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:167:5:   required from 'struct boost::CopyConstructible<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIteratorConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ReadableIteratorConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ReadableIteratorConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:30:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::CopyConstructible<TT>::~CopyConstructible() [with TT = const char*]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:167:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  167 |     BOOST_CONCEPT_USAGE(CopyConstructible) {
      |     ^~~~~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost_concepts::ReadableIterator<const char*>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost_concepts::ReadableIterator<const char*> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:48:7:   required from 'struct boost_concepts::ReadableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:40:3:   required from 'struct boost_concepts::ReadableIteratorConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ReadableIteratorConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ReadableIteratorConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ReadableIteratorConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:30:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost_concepts::ReadableIterator<Iterator>::~ReadableIterator() [with Iterator = const char*]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:48:7: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
   48 |       BOOST_CONCEPT_USAGE(ReadableIterator)
      |       ^~~~~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5:   required from 'struct boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::incrementable_traversal_tag> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   [ skipping 6 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::Convertible<X, Y>::~Convertible() [with X = boost::iterators::random_access_traversal_tag; Y = boost::iterators::incrementable_traversal_tag]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  208 |     BOOST_CONCEPT_USAGE(Convertible) {
      |     ^~~~~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost_concepts::IncrementableIterator<const char*>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost_concepts::IncrementableIterator<const char*> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:120:7:   required from 'struct boost_concepts::IncrementableIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:129:3:   required from 'struct boost_concepts::SinglePassIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   [ skipping 2 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost_concepts::IncrementableIterator<Iterator>::~IncrementableIterator() [with Iterator = const char*]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:120:7: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  120 |       BOOST_CONCEPT_USAGE(IncrementableIterator)
      |       ^~~~~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::EqualityComparable<const char*>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::EqualityComparable<const char*> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:233:5:   required from 'struct boost::EqualityComparable<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:129:3:   required from 'struct boost_concepts::SinglePassIterator<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   [ skipping 2 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::EqualityComparable<TT>::~EqualityComparable() [with TT = const char*]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:233:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  233 |     BOOST_CONCEPT_USAGE(EqualityComparable) {
      |     ^~~~~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5:   required from 'struct boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::single_pass_traversal_tag> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   [ skipping 5 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::Convertible<X, Y>::~Convertible() [with X = boost::iterators::random_access_traversal_tag; Y = boost::iterators::single_pass_traversal_tag]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  208 |     BOOST_CONCEPT_USAGE(Convertible) {
      |     ^~~~~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::DefaultConstructible<const char*>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::DefaultConstructible<const char*> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:137:5:   required from 'struct boost::DefaultConstructible<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversal<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/iterator/iterator_concepts.hpp:141:3:   required from 'struct boost_concepts::ForwardTraversalConcept<const char*>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost_concepts::ForwardTraversalConcept<const char*>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::DefaultConstructible<TT>::~DefaultConstructible() [with TT = const char*]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:137:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  137 |     BOOST_CONCEPT_USAGE(DefaultConstructible) {
      |     ^~~~~~~~~~~~~~~~~~~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp: In instantiation of 'boost::concepts::usage_requirements<Model>::~usage_requirements() [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag>]':
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:39:47:   required from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::usage_requirements<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag> >]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5:   required from 'struct boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:32:62:   required by substitution of 'template<class Model> boost::concepts::detail::yes boost::concepts::detail::has_constraints_(Model*, boost::concepts::detail::wrap_constraints<Model, (& Model::constraints)>*) [with Model = boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag>]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost::Convertible<boost::iterators::random_access_traversal_tag, boost::iterators::forward_traversal_tag> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   [ skipping 4 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:42:5:   required from 'const bool boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >::value'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/has_constraints.hpp:45:51:   required from 'struct boost::concepts::not_satisfied<boost_concepts::ForwardTraversalConcept<const char*> >'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/detail/general.hpp:51:8:   required from 'struct boost::concepts::requirement_<void (*)(boost_concepts::ForwardTraversalConcept<const char*>)>'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:31:9:   required from 'bool boost::spirit::x3::parse_main(Iterator&, Iterator, const Parser&, Attribute&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser; Attribute = const boost::spirit::x3::unused_type]'
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/spirit/home/x3/core/parse.hpp:72:26:   required from 'bool boost::spirit::x3::parse(Iterator&, Iterator, const Parser&) [with Iterator = const char*; Parser = boost::spirit::x3::eps_parser]'
prog.cc:7:39:   required from here
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:16:48: warning: 'this' pointer null [-Wnonnull]
   16 |     ~usage_requirements() { ((Model*)0)->~Model(); }
      |                             ~~~~~~~~~~~~~~~~~~~^~
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept/usage.hpp:30:7: note: in a call to non-static member function 'boost::Convertible<X, Y>::~Convertible() [with X = boost::iterators::random_access_traversal_tag; Y = boost::iterators::forward_traversal_tag]'
   30 |       ~model()
      |       ^
/opt/wandbox/boost-1.73.0/gcc-head/include/boost/concept_check.hpp:208:5: note: in expansion of macro 'BOOST_CONCEPT_USAGE'
  208 |     BOOST_CONCEPT_USAGE(Convertible) {
      |     ^~~~~~~~~~~~~~~~~~~

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