[clang] [Clang] [C++26] Implement P2573R2: `= delete("should have a reason");` (PR #86526)

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@@ -2013,6 +2013,12 @@ class FunctionDecl : public DeclaratorDecl,
     DefaultedFunctionInfo *DefaultedInfo;
   };
 
+  /// Message that indicates why this function was deleted.
+  ///
+  /// FIXME: Figure out where to actually put this; maybe in the
+  /// 'DefaultedInfo' above?
+  StringLiteral *DeletedMessage;
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Sirraide wrote:

Just refactored that; see my comment below.

https://github.com/llvm/llvm-project/pull/86526