[clang] [Modules] Delay deserialization of preferred_name attribute at r… (PR #122726)

[Chuanqi Xu via cfe-commits]

================
@@ -1205,6 +1205,23 @@ class ASTReader
   /// been completed.
   std::deque<PendingDeclContextInfo> PendingDeclContextInfos;
 
+  /// Deserialization of some attributes must be deferred since they refer
+  /// to themselves in their type (e.g., preferred_name attribute refers to the
+  /// typedef that refers back to the template specialization of the template
+  /// that the attribute is attached to).
+  /// More attributes that store TypeSourceInfo might be potentially affected,
+  /// see https://github.com/llvm/llvm-project/issues/56490 for details.
+  struct DeferredAttribute {
+    uint64_t RecordIdx;
----------------
ChuanqiXu9 wrote:

nit: Add a comment to the field. e.g., something like the Index of the delayed attribute in the Record of the targeted decl.

https://github.com/llvm/llvm-project/pull/122726