Also fix TrivialFunctionAnalysisVisitor to recognize std::bit_cast as trivial

Author: rniwa

clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp

@@ -645,6 +645,10 @@ class TrivialFunctionAnalysisVisitor
     auto *Callee = CE->getDirectCallee();
     if (!Callee)
       return false;
+
+    if (isPtrConversion(Callee))
+      return true;
+
     const auto &Name = safeGetName(Callee);
 
     if (Callee->isInStdNamespace() &&
@@ -658,7 +662,7 @@ class TrivialFunctionAnalysisVisitor
         Name == "isMainThreadOrGCThread" || Name == "isMainRunLoop" ||
         Name == "isWebThread" || Name == "isUIThread" ||
         Name == "mayBeGCThread" || Name == "compilerFenceForCrash" ||
-        Name == "bitwise_cast" || isTrivialBuiltinFunction(Callee))
+        isTrivialBuiltinFunction(Callee))
       return true;
 
     return IsFunctionTrivial(Callee);

clang/test/Analysis/Checkers/WebKit/uncounted-local-vars.cpp

@@ -205,6 +205,20 @@ void foo2() {
 }
 } // namespace guardian_casts
 
+namespace casts {
+
+RefCountable* provide() { return nullptr; }
+RefCountable* downcast(RefCountable*);
+template<class T> T* bitwise_cast(T*);
+template<class T> T* bit_cast(T*);
+
+  void foo() {
+    auto* cast1 = downcast(provide());
+    auto* cast2 = bitwise_cast(provide());
+    auto* cast3 = bit_cast(provide());
+   }
+} // namespace casts
+
 namespace guardian_ref_conversion_operator {
 void foo() {
   Ref<RefCountable> rc;