265.md

<details open><summary>Info</summary><p>

* **Did you know that C++23 added Attributes on Lambda-Expressions?**

  * https://wg21.link/P2173

</p></details><details open><summary>Example</summary><p>

```cpp
constexpr auto foo = [] [[deprecated]] { };

int main() {
    foo(); // operator() is deprecated
}
```

> https://godbolt.org/z/MaeTnG9eb

</p></details><details open><summary>Puzzle</summary><p>

* **Can you implement variable template lambda expression `foo` which is marked nodiscard for integral types?**

```cpp
//TODO foo

int main() {
    using namespace boost::ut;

    "should be callable for non integral types"_test = [] {
        foo<float>();
        foo<double>();
    };

    "should verify the result for integral types"_test = [] {
        expect(0_c == foo<char>());
        expect(not foo<bool>());
        expect(0_s == foo<short>());
        expect(0_i == foo<int>());
    };

    "should ignore the result for integral types"_test = [] {
        /*TODO*/ foo<char>();
        /*TODO*/ foo<bool>();
        /*TODO*/ foo<short>();
        /*TODO*/ foo<int>();
    };
}
```

> https://godbolt.org/z/fKfjsbWoh

</p></details><details><summary>Solutions</summary><p>