[clang] [Clang] Support MSPropertyRefExpr as placement arg to new-expression (PR #75883)

[Erich Keane via cfe-commits]

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@@ -2286,6 +2286,9 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   bool PassAlignment = getLangOpts().AlignedAllocation &&
                        Alignment > NewAlignment;
 
+  if (CheckArgsForPlaceholders(PlacementArgs))
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erichkeane wrote:

A bit of both, this should check the behavior of other expression types.  This changes general 'placement new' behaviors, so it looks like it changes existing placement new behaviors that are seemingly untested, so should be showing off  THOSE as well.

https://github.com/llvm/llvm-project/pull/75883