[clang] [BoundsSafety][Clang][Sema][AST] Introduce CThisExpr for C __counted_by attributes (PR #199241)

[Henrik G. Olsson via cfe-commits]

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@@ -1510,6 +1510,46 @@ class DeclRefExpr final
   }
 };
 
+class CThisExpr : public Expr {
+  SourceLocation Loc;
+  bool IsImplicit;
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hnrklssn wrote:

Do we expect that we'll ever support explicit nodes of this kind?

https://github.com/llvm/llvm-project/pull/199241