[clang] [clang] Add tests for some CWG 5xx issues (PR #87909)

[Vlad Serebrennikov via cfe-commits]

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@@ -265,6 +269,18 @@ namespace dr527 { // dr527: na
   int ax = a.x, bx = b.x, cx = c.x, dx = d.x, ex = E::e->x, fx = F::f->x;
 }
 
+namespace dr528 { // dr528: 2.7
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Endilll wrote:

For NAD issues, we write tests that check for status quo, and report the first version where we exhibit the behavior CWG wants.

https://github.com/llvm/llvm-project/pull/87909