[libcxx-commits] [PATCH] D110994: [libc++] Make test_allocator constexpr-friendly for constexpr string/vector

[Louis Dionne via Phabricator via libcxx-commits]

ldionne added a comment.

There is some overlap with D68365 <https://reviews.llvm.org/D68365> (let's move forward with this patch and I can rebase onto it). You might want to take a look at what I did in D68365 <https://reviews.llvm.org/D68365> in case that gives you ideas. I also think we'll want to pick parts of D68365 <https://reviews.llvm.org/D68365> out (like the `shared_ptr` emulation).



================
Comment at: libcxx/test/support/test_allocator.h:256-263
 #if TEST_STD_VER < 11
-    void construct(pointer p, const T& val)
-        {::new(static_cast<void*>(p)) T(val);}
+  void construct(pointer p, const T& val) { ::new (static_cast<void*>(p)) T(val); }
 #else
-    template <class U> void construct(pointer p, U&& val)
-        {::new(static_cast<void*>(p)) T(std::forward<U>(val));}
+  template <class U>
+  void construct(pointer p, U&& val) {
+    ::new (static_cast<void*>(p)) T(std::forward<U>(val));
+  }
----------------
Based on what I did in D68365, I think the correct definition of this would be:

```
#if TEST_STD_VER < 11
    void construct(pointer p, const T& val) {
        ::new(static_cast<void*>(p)) T(val);
    }
#elif TEST_STD_VER < 20
    template <class U>
    void construct(pointer p, U&& val) {
        ::new(static_cast<void*>(p)) T(std::forward<U>(val));
    }
#else
    template <class U>
    constexpr void construct(pointer p, U&& val) {
        std::construct_at(p, std::forward<U>(val));
    }
#endif
```



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110994/new/

https://reviews.llvm.org/D110994