[clang] [clang] Propagate definition data to all redecls (PR #170090)

[Chuanqi Xu via cfe-commits]

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@@ -2107,8 +2107,8 @@ void ASTDeclMerger::MergeDefinitionData(
     auto *Def = DD.Definition;
     DD = std::move(MergeDD);
     DD.Definition = Def;
-    while ((Def = Def->getPreviousDecl()))
-      cast<CXXRecordDecl>(Def)->DefinitionData = ⅅ
+    for (auto *D : Def->redecls())
+      cast<CXXRecordDecl>(D)->DefinitionData = ⅅ
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ChuanqiXu9 wrote:

If you like, I hope you can introduce `noload_redecls()` here. But I don't block this.

https://github.com/llvm/llvm-project/pull/170090