[libcxx-commits] [libcxx] [libc++] P2770R0: "Stashing stashing iterators for proper flattening" (PR #66033)

[Louis Dionne via libcxx-commits]

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+//===----------------------------------------------------------------------===//
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ldionne wrote:

You need to split this test into two tests. Right now, this code is only compiled, but never run (because `.verify.cpp` doesn't run stuff, it only compiles). So:

```c++
//
// as-lvalue.lifetimebound.verify.cpp
//

void f() {
  [[maybe_unused]] auto& check = std::ranges::__as_lvalue(0); // expected-warning {{temporary bound to local reference 'check' will be destroyed at the end of the full-expression}}
}

//
// as-lvalue.pass.cpp
//

constexpr bool test() {
  // Check glvalue
  {
    int lvalue{};
    [[maybe_unused]] std::same_as<int&> decltype(auto) check = std::ranges::__as_lvalue(lvalue);
  }

  // Check xvalue
  {
    int xvalue{};
    [[maybe_unused]] std::same_as<int&> decltype(auto) check = std::ranges::__as_lvalue(std::move(xvalue));
  }

  return true;
}

int main(int, char**) {
  test();
  static_assert(test());
  return 0;
}
```

https://github.com/llvm/llvm-project/pull/66033