[clang] [clang]: reflection operator parsing for global namespace and primitive types (PR #164692)

[Nhat Nguyen via cfe-commits]

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@@ -1848,6 +1848,11 @@ def err_placeholder_expected_auto_or_decltype_auto : Error<
   "expected 'auto' or 'decltype(auto)' after concept name">;
 }
 
+let CategoryName = "Reflection Issue" in {
+def err_cannot_reflect_operand : Error<
+  "cannot reflect the provided operand">;
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changkhothuychung wrote:

I changed to `expected reflectable entity`. As we implement parsing reflect-expression in upcoming PRs, I guess we will have a better idea how to introduce better diagnostic, for now it could hit the diagnostic simply because its not implemented yet. 

https://github.com/llvm/llvm-project/pull/164692