Modernize ranges::swap_ranges and ranges::distance

[Michael Schellenberger Costa (miscco)]

This swaps the implementation of the the last two algorithms to bridge the distance to the other ones.

[Casey Carter (CaseyCarter)]

This swaps the implementation of the the last two algorithms to bridge the distance to the other ones.

I think I'm having a negative influence on you ;)

[Michael Schellenberger Costa (miscco)]

BTW can somebody tell my why this breaks, because it totally works on my machine (Aka why does it not swap the ranges?)

[statementreply]

why does it not swap the ranges?

There is a bug in ranges::iter_swap (#1067).

[Michael Schellenberger Costa (miscco)]

why does it not swap the ranges?

There is a bug in ranges::iter_swap (#1067).

Hooray for increased test coverage

[Casey Carter (CaseyCarter)]

This is blocked on #1072. Michael Schellenberger Costa (@miscco), could you verify that #1072 fixes this?

[Michael Schellenberger Costa (miscco)]

At least on my machine it works now, but it did before so ...

[statementreply]

stl-lit.py: C:\Users\He\source\repos\STL\tests\utils\stl\test\format.py:203: note: Build step failed unexpectedly.
Command: "C:\Program Files\LLVM\bin\clang-cl.EXE" "/FeC:\Users\He\source\repos\STL\out\build\x64\tests\std\tests\P0896R4_ranges_alg_swap_ranges\15\P0896R4_ranges_alg_swap_ranges.exe" "/FoC:\Users\He\source\repos\STL\out\build\x64\tests\std\tests\P0896R4_ranges_alg_swap_ranges\15\P0896R4_ranges_alg_swap_ranges.obj" "/IC:\Users\He\source\repos\STL\out\build\x64\out\inc" "/IC:/Users/He/source/repos/STL/llvm-project/libcxx/test/support" "/IC:/Users/He/source/repos/STL/tests/std/include" "-m64" "/nologo" "/Od" "/W4" "/w14061" "/w14242" "/w14265" "/w14582" "/w14583" "/w14587" "/w14588" "/w14749" "/w14841" "/w14842" "/w15038" "/w15214" "/w15215" "/w15216" "/w15217" "/sdl" "/WX" "/Zc:strictStrings" "/D_ENABLE_STL_INTERNAL_CHECK" "/bigobj" "/FIforce_include.hpp" "/w14365" "/D_ENFORCE_FACET_SPECIALIZATIONS=1" "/w14640" "/Zc:threadSafeInit-" "/EHsc" "/std:c++latest" "-fno-ms-compatibility" "-fno-delayed-template-parsing" "/MD" "C:\Users\He\source\repos\STL\tests\std\tests\P0896R4_ranges_alg_swap_ranges\test.cpp" "/link" "/LIBPATH:C:\Users\He\source\repos\STL\out\build\x64\out\lib\amd64" "/LIBPATH:C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\VC\Tools\MSVC\14.27.29109\lib\x64" "/MANIFEST:EMBED"
Exit Code: 1
Standard Error:
--
C:\Users\He\source\repos\STL\tests\std\tests\P0896R4_ranges_alg_swap_ranges\test.cpp(67,19): error: static_assert expression is not an integral constant expression
    STATIC_ASSERT((test_in_in<instantiator, int, int>(), true));
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
C:/Users/He/source/repos/STL/tests/std/include\range_algorithm_support.hpp(15,42): note: expanded from macro 'STATIC_ASSERT'
#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
                                         ^~~~~~~~~~~
C:\Users\He\source\repos\STL\out\build\x64\out\inc\xutility(682,111): note: constexpr evaluation hit maximum step limit; possible infinite loop?
            _NODISCARD constexpr decltype(auto) operator()(_Ty&& _Val) const noexcept(_Choice<_Ty>._No_throw) {
                                                                                                              ^
C:\Users\He\source\repos\STL\out\build\x64\out\inc\xutility(1033,57): note: in call to '&iter_move->operator()(_First2)'
            iter_value_t<remove_reference_t<_Xty>> _Tmp(_RANGES iter_move(_XVal));
                                                        ^
C:\Users\He\source\repos\STL\out\build\x64\out\inc\yvals_core.h(1218,20): note: expanded from macro '_RANGES'
#define _RANGES    ::std::ranges::
                   ^
C:\Users\He\source\repos\STL\out\build\x64\out\inc\xutility(1071,25): note: in call to '_Iter_exchange_move(_First2, _First1)'
                        _Iter_exchange_move(static_cast<_Ty2&&>(_Val2), static_cast<_Ty1&&>(_Val1));
                        ^
C:\Users\He\source\repos\STL\out\build\x64\out\inc\algorithm(3273,17): note: in call to '&iter_swap->operator()(_First1, _First2)'
                _RANGES iter_swap(_First1, _First2);
                ^
C:\Users\He\source\repos\STL\out\build\x64\out\inc\yvals_core.h(1218,20): note: expanded from macro '_RANGES'
#define _RANGES    ::std::ranges::
                   ^
C:\Users\He\source\repos\STL\out\build\x64\out\inc\algorithm(3254,29): note: in call to '_Swap_ranges_unchecked({&input1[0]}, {&input1[3]}, {&input2[0]}, {&input2[3]})'
            auto _UResult = _Swap_ranges_unchecked(
                            ^
C:\Users\He\source\repos\STL\tests\std\tests\P0896R4_ranges_alg_swap_ranges\test.cpp(54,27): note: in call to '&swap_ranges->operator()(wrapped_input1, wrapped_input2)'
            auto result = swap_ranges(wrapped_input1, wrapped_input2);
                          ^
C:/Users/He/source/repos/STL/tests/std/include\range_algorithm_support.hpp(877,9): note: in call to 'call()'
        Continuation::template call<Args...,
        ^
C:/Users/He/source/repos/STL/tests/std/include\range_algorithm_support.hpp(904,9): note: in call to 'call()'
        Continuation::template call<Args...,
        ^
C:/Users/He/source/repos/STL/tests/std/include\range_algorithm_support.hpp(1038,5): note: in call to 'call()'
    with_input_ranges<with_input_ranges<Instantiator, Element2>, Element1>::call();
    ^
C:\Users\He\source\repos\STL\tests\std\tests\P0896R4_ranges_alg_swap_ranges\test.cpp(67,20): note: in call to 'test_in_in()'
    STATIC_ASSERT((test_in_in<instantiator, int, int>(), true));
                   ^
1 error generated.

clang ran out of constexpr evaluation limit on my machine.

[Casey Carter (CaseyCarter)]

This is no longer blocked on #1062: we should be able to merge master and get this cleaned up and across the finish line.

[Stephan T. Lavavej (StephanTLavavej)]

Looks good - I will push a change to fix a comment (I verified against WG21-N4861 that the test code was correct) and to complete the using namespace std; change. Thanks!

[Stephan T. Lavavej (StephanTLavavej)]

Thanks for the ongoing modernizations! 🚀