[clang-tools-extra] [clang-tidy] do not diagnose array types within implicit instantiations of a template (PR #132924)

[Baranov Victor via cfe-commits]

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@@ -39,6 +39,51 @@ AST_MATCHER(clang::ParmVarDecl, isArgvOfMain) {
   return FD ? FD->isMain() : false;
 }
 
+AST_MATCHER(clang::TypeLoc, isWithinImplicitTemplateInstantiation) {
+  const auto IsImplicitTemplateInstantiation = [](const auto *Node) {
+    return (Node != nullptr) &&
+           (Node->getTemplateSpecializationKind() == TSK_ImplicitInstantiation);
+  };
+
+  DynTypedNodeList ParentNodes = Finder->getASTContext().getParents(Node);
+  const clang::NamedDecl *ParentDecl = nullptr;
+  while (!ParentNodes.empty()) {
+    const DynTypedNode &ParentNode = ParentNodes[0];
+    if (IsImplicitTemplateInstantiation(
+            ParentNode.template get<clang::CXXRecordDecl>()) ||
+        IsImplicitTemplateInstantiation(
+            ParentNode.template get<clang::FunctionDecl>()) ||
+        IsImplicitTemplateInstantiation(
+            ParentNode.template get<clang::VarDecl>()))
+      return true;
+
+    // in case of a `NamedDecl` as parent node, it is more efficient to proceed
+    // with the upward traversal via DeclContexts (see below) instead of via
+    // parent nodes
+    if (ParentDecl = ParentNode.template get<clang::NamedDecl>())
+      break;
+
+    ParentNodes = Finder->getASTContext().getParents(ParentNode);
+  }
+
+  if (ParentDecl != nullptr) {
+    const clang::DeclContext *DeclContext = ParentDecl->getDeclContext();
+    while (DeclContext != nullptr) {
+      for (const clang::Decl *Decl : DeclContext->decls()) {
+        if (IsImplicitTemplateInstantiation(
+                dyn_cast<clang::CXXRecordDecl>(Decl)) ||
+            IsImplicitTemplateInstantiation(
+                dyn_cast<clang::FunctionDecl>(Decl)) ||
+            IsImplicitTemplateInstantiation(dyn_cast<clang::VarDecl>(Decl)))
----------------
vbvictor wrote:

Could these calls to 3 functions be refactored in a separate function to avoid duplicates with L52-57

https://github.com/llvm/llvm-project/pull/132924