[clang] [libcxx] [clang] Warn about memset/memcpy to NonTriviallyCopyable types (PR #111434)

[Nikolas Klauser via cfe-commits]

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@@ -638,7 +638,7 @@ __uninitialized_allocator_relocate(_Alloc& __alloc, _Tp* __first, _Tp* __last, _
     __guard.__complete();
     std::__allocator_destroy(__alloc, __first, __last);
   } else {
-    __builtin_memcpy(__result, __first, sizeof(_Tp) * (__last - __first));
+    __builtin_memcpy((void*)__result, __first, sizeof(_Tp) * (__last - __first));
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philnik777 wrote:

I think it would be better to make these `static_cast`s to make it obvious that we're casting from a different pointer. Could you also add a comment like `// casting to void* to suppress clang complaining that this is technically UB`?

https://github.com/llvm/llvm-project/pull/111434