[Bug c++/106567] New: An array with a dependent type and initializer-deduced bound is treated as an array of unknown bound when captured in a lambda

ville.voutilainen at gmail dot com gcc-bugzilla@gcc.gnu.org
Mon Aug 8 20:36:10 GMT 2022


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106567

            Bug ID: 106567
           Summary: An array with a dependent type and initializer-deduced
                    bound is treated as an array of unknown bound when
                    captured in a lambda
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ville.voutilainen at gmail dot com
  Target Milestone: ---

Test:

#include <vector>

template <class T>
void urgh()
{
    using V = typename T::value_type;

    const V x[] = {V(0), V(1), V(2), V(0)};

    [&]() {
        for (auto& v : x) {}
    }();
}

void no_urgh()
{
    using V = int;

    const V x[] = {V(0), V(1), V(2), V(0)};

    [&]() {
        for (auto& v : x) {}
    }();
}

int main()
{
    no_urgh();
    urgh<std::vector<int>>();
}

Live demo at https://wandbox.org/permlink/9hSQdxhNzgDCuXYZ

prog.cc: In instantiation of 'void urgh() [with T = std::vector<int>]':
prog.cc:29:27:   required from here
prog.cc:11:9: error: range-based 'for' expression of type 'const int []' has
incomplete type
   11 |         for (auto& v : x) {}
      |         ^~~


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