[Bug c++/106864] New: Unexpected capture of "constexpr int" variable inside lambda

[a.elovikov at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106864

            Bug ID: 106864
           Summary: Unexpected capture of "constexpr int" variable inside
                    lambda
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: a.elovikov at gmail dot com
  Target Milestone: ---

void bad() {
  constexpr int x = 1;
  auto Outer = [&]() {
    auto L = [=]() {
      for (int i = 0; i < x; ++i) {
      }
    };
    static_assert(sizeof(L) == 1); // fails
  };
}

void good() {
  constexpr int x = 1;
  auto L = [=]() {
    for (int i = 0; i < x; ++i) {
    }
  };
  static_assert(sizeof(L) == 1);  // passes
}

Not sure if that's a bug from the standard conformance point of view, but I'd
expect the L not to capture constexpr variable in both cases.

Sizeof is one in both cases with clang and (MSVC v19.latest + "/std:c++latest
/c") on godbolt.