[clang] [webkit.RefCntblBaseVirtualDtor] Allow CRTP classes without a virtual destructor. (PR #92837)

[NAKAMURA Takumi via cfe-commits]

================
@@ -11,16 +11,116 @@
 #include "PtrTypesSemantics.h"
 #include "clang/AST/CXXInheritance.h"
 #include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/AST/StmtVisitor.h"
 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
 #include "clang/StaticAnalyzer/Core/Checker.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SetVector.h"
 #include <optional>
 
 using namespace clang;
 using namespace ento;
 
 namespace {
+
+class DerefFuncDeleteExprVisitor
+    : public ConstStmtVisitor<DerefFuncDeleteExprVisitor, bool> {
+  // Returns true if any of child statements return true.
+  bool VisitChildren(const Stmt *S) {
+    for (const Stmt *Child : S->children()) {
+      if (Child && Visit(Child))
+        return true;
+    }
+    return false;
+  }
+
+  bool VisitBody(const Stmt *Body) {
+    if (!Body)
+      return false;
+
+    auto [It, IsNew] = VisitedBody.insert(Body);
+    if (!IsNew) // This body is recursive
+      return false;
+
+    return Visit(Body);
+  }
+
+public:
+  DerefFuncDeleteExprVisitor(const TemplateArgumentList &ArgList,
+                             const CXXRecordDecl *ClassDecl)
+      : ArgList(&ArgList), ClassDecl(ClassDecl) {}
+
+  DerefFuncDeleteExprVisitor(const CXXRecordDecl *ClassDecl)
+      : ClassDecl(ClassDecl) {}
+
+  std::optional<bool> HasSpecializedDelete(CXXMethodDecl *Decl) {
+    if (auto *Body = Decl->getBody())
+      return VisitBody(Body);
+    if (auto *Tmpl = Decl->getTemplateInstantiationPattern())
----------------
chapuni wrote:

This causes a warning.

```
clang/lib/StaticAnalyzer/Checkers/WebKit/RefCntblBaseVirtualDtorChecker.cpp:61:15: warning: variable 'Tmpl' set but not used [-Wunused-but-set-variable]
```

https://github.com/llvm/llvm-project/pull/92837