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













share|improve this question




share|improve this question








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












1 Answer
1






active

oldest

votes


















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




















    Your Answer






    StackExchange.ifUsing("editor", function ()
    StackExchange.using("externalEditor", function ()
    StackExchange.using("snippets", function ()
    StackExchange.snippets.init();
    );
    );
    , "code-snippets");

    StackExchange.ready(function()
    var channelOptions =
    tags: "".split(" "),
    id: "1"
    ;
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function()
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled)
    StackExchange.using("snippets", function()
    createEditor();
    );

    else
    createEditor();

    );

    function createEditor()
    StackExchange.prepareEditor(
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader:
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    ,
    onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    );



    );













    draft saved

    draft discarded


















    StackExchange.ready(
    function ()
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53258372%2fconstexpr-initializer-list-of-string-views%23new-answer', 'question_page');

    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    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

























      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























        0












        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

        1,14111438




        1,14111438



























            draft saved

            draft discarded
















































            Thanks for contributing an answer to Stack Overflow!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid


            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.

            To learn more, see our tips on writing great answers.





            Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


            Please pay close attention to the following guidance:


            • Please be sure to answer the question. Provide details and share your research!

            But avoid


            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.

            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53258372%2fconstexpr-initializer-list-of-string-views%23new-answer', 'question_page');

            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            這個網誌中的熱門文章

            How to read a connectionString WITH PROVIDER in .NET Core?

            In R, how to develop a multiplot heatmap.2 figure showing key labels successfully

            Museum of Modern and Contemporary Art of Trento and Rovereto