[Bug c++/86253] New: N3639 array of runtime bound

[zhonghao at pku dot org.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86253

            Bug ID: 86253
           Summary: N3639 array of runtime bound
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhonghao at pku dot org.cn
  Target Milestone: ---

The code is as follow:

int main(int argc, char** argv)
{
 int x[1][argc];

 [&x](int i)
 {
 x[0][i] = 0;
 }(5);

 return 0;
}

clang++ accepts the code, but g++ produces error messages:
capture of variably-modified type ‘int [1][argc]’ that is not an N3639 array of
runtime bound
because the array element type ‘int [argc]’ has variable size

I thought that this is a bug in clang, and reported it to
https://bugs.llvm.org/show_bug.cgi?id=37843

However, Richard Smith told me that clang++ can produce this message, since
clang++ has a feature that GCC's extension lacks. Does gcc have plan to
implement that feature?