[clang] [Clang] Implement P2747 constexpr placement new (PR #104586)

[Aaron Ballman via cfe-commits]

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@@ -994,7 +994,7 @@ namespace placement_new_delete {
   constexpr bool bad(int which) {
     switch (which) {
     case 0:
-      delete new (placement_new_arg{}) int; // expected-note {{call to placement 'operator new'}}
+      delete new (placement_new_arg{}) int; // expected-note {{this placement new expression is not yet supported in constant expressions}}
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AaronBallman wrote:

Same here as above.

https://github.com/llvm/llvm-project/pull/104586