constexpr Initializer list of string views












1














I'm trying to make a constexpr initializer list of some string constants. I think this should be possible in C++17, but I can't get it to compile in MSVC.



#include <string_view>

using namespace std::literals::string_view_literals;

const constexpr std::initializer_list<std::string_view> some_strings{
"asdf"sv
};


This gives the following error message:



error C2131: expression did not evaluate to a constant
note: failure was caused by non-constant arguments or reference to a non-constant symbol
note: see usage of '$S1'


I can't figure out which part would be non-constexpr:




  • std::string_view's operator"" is constexpr

  • std::initializer_list's constructor is constexpr as well


Any ideas? Is this possibly just a bug in visual studio? What is '$S1' referenced in the error message?



EDIT: Visual Studio 15.8.9










share|improve this question
























  • Latest MSVC. They announced 100% conformance with the standard in 15.7, and I'm using 15.8.9.
    – leecbaker
    Nov 12 at 8:43
















1














I'm trying to make a constexpr initializer list of some string constants. I think this should be possible in C++17, but I can't get it to compile in MSVC.



#include <string_view>

using namespace std::literals::string_view_literals;

const constexpr std::initializer_list<std::string_view> some_strings{
"asdf"sv
};


This gives the following error message:



error C2131: expression did not evaluate to a constant
note: failure was caused by non-constant arguments or reference to a non-constant symbol
note: see usage of '$S1'


I can't figure out which part would be non-constexpr:




  • std::string_view's operator"" is constexpr

  • std::initializer_list's constructor is constexpr as well


Any ideas? Is this possibly just a bug in visual studio? What is '$S1' referenced in the error message?



EDIT: Visual Studio 15.8.9










share|improve this question
























  • Latest MSVC. They announced 100% conformance with the standard in 15.7, and I'm using 15.8.9.
    – leecbaker
    Nov 12 at 8:43














1












1








1







I'm trying to make a constexpr initializer list of some string constants. I think this should be possible in C++17, but I can't get it to compile in MSVC.



#include <string_view>

using namespace std::literals::string_view_literals;

const constexpr std::initializer_list<std::string_view> some_strings{
"asdf"sv
};


This gives the following error message:



error C2131: expression did not evaluate to a constant
note: failure was caused by non-constant arguments or reference to a non-constant symbol
note: see usage of '$S1'


I can't figure out which part would be non-constexpr:




  • std::string_view's operator"" is constexpr

  • std::initializer_list's constructor is constexpr as well


Any ideas? Is this possibly just a bug in visual studio? What is '$S1' referenced in the error message?



EDIT: Visual Studio 15.8.9










share|improve this question















I'm trying to make a constexpr initializer list of some string constants. I think this should be possible in C++17, but I can't get it to compile in MSVC.



#include <string_view>

using namespace std::literals::string_view_literals;

const constexpr std::initializer_list<std::string_view> some_strings{
"asdf"sv
};


This gives the following error message:



error C2131: expression did not evaluate to a constant
note: failure was caused by non-constant arguments or reference to a non-constant symbol
note: see usage of '$S1'


I can't figure out which part would be non-constexpr:




  • std::string_view's operator"" is constexpr

  • std::initializer_list's constructor is constexpr as well


Any ideas? Is this possibly just a bug in visual studio? What is '$S1' referenced in the error message?



EDIT: Visual Studio 15.8.9







visual-c++ c++17 constexpr initializer-list






share|improve this question















share|improve this question













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edited Nov 12 at 8:42

























asked Nov 12 at 8:34









leecbaker

1,67422438




1,67422438












  • Latest MSVC. They announced 100% conformance with the standard in 15.7, and I'm using 15.8.9.
    – leecbaker
    Nov 12 at 8:43


















  • Latest MSVC. They announced 100% conformance with the standard in 15.7, and I'm using 15.8.9.
    – leecbaker
    Nov 12 at 8:43
















Latest MSVC. They announced 100% conformance with the standard in 15.7, and I'm using 15.8.9.
– leecbaker
Nov 12 at 8:43




Latest MSVC. They announced 100% conformance with the standard in 15.7, and I'm using 15.8.9.
– leecbaker
Nov 12 at 8:43












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It seems like a bug on older versions: https://godbolt.org/z/YICeqi



I just tried your code on v15.9.2 and it works fine.






share|improve this answer





















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    It seems like a bug on older versions: https://godbolt.org/z/YICeqi



    I just tried your code on v15.9.2 and it works fine.






    share|improve this answer


























      0














      It seems like a bug on older versions: https://godbolt.org/z/YICeqi



      I just tried your code on v15.9.2 and it works fine.






      share|improve this answer
























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        0








        0






        It seems like a bug on older versions: https://godbolt.org/z/YICeqi



        I just tried your code on v15.9.2 and it works fine.






        share|improve this answer












        It seems like a bug on older versions: https://godbolt.org/z/YICeqi



        I just tried your code on v15.9.2 and it works fine.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 23 at 5:54









        Mac

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        1,14111439






























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