[clang] [clang-tools-extra] Handle recording inheritance for templates (PR #177273)

[via cfe-commits]

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@@ -193,6 +194,22 @@ class TypeIndexer : public RecursiveASTVisitor<TypeIndexer> {
     return true;
   }
 
+  bool TraverseSubstTemplateTypeParmTypeLoc(SubstTemplateTypeParmTypeLoc TL,
+                                            bool TraverseQualifier) {
+    const auto *T = TL.getTypePtr();
+    if (!T)
+      return true;
+    auto QT = T->getReplacementType();
+    if (QT.isNull())
+      return true;
+    auto *CXXRD = QT->getAsCXXRecordDecl();
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timon-ul wrote:

I guess this also means we do not directly want to add all instantiations with refs in this PR? Since I had added numbers for that as mentioned [here](https://github.com/llvm/llvm-project/pull/177273#issuecomment-3786918708). Makessense though if it is more work than just some minor tweaks.

https://github.com/llvm/llvm-project/pull/177273