[webkit.UncountedLambdaCapturesChecker] Treat a copy capture of a CheckedPtr object as safe (llvm#138068)

Allow copy capture of a reference to a CheckedPtr capable object since
such a capture will copy the said object instead of keeping a dangling
reference to the object.

Author: rniwa

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

@@ -384,6 +384,9 @@ class RawPtrRefLambdaCapturesChecker
         }
         QualType CapturedVarQualType = CapturedVar->getType();
         auto IsUncountedPtr = isUnsafePtr(CapturedVar->getType());
+        if (C.getCaptureKind() == LCK_ByCopy &&
+            CapturedVarQualType->isReferenceType())
+          continue;
         if (IsUncountedPtr && *IsUncountedPtr)
           reportBug(C, CapturedVar, CapturedVarQualType, L);
       } else if (C.capturesThis() && shouldCheckThis) {

clang/test/Analysis/Checkers/WebKit/uncounted-lambda-captures.cpp

@@ -137,13 +137,11 @@ void references() {
   RefCountable automatic;
   RefCountable& ref_countable_ref = automatic;
   auto foo1 = [ref_countable_ref](){ ref_countable_ref.constMethod(); };
-  // expected-warning@-1{{Captured reference 'ref_countable_ref' to uncounted type is unsafe [webkit.UncountedLambdaCapturesChecker]}}
   auto foo2 = [&ref_countable_ref](){ ref_countable_ref.method(); };
   // expected-warning@-1{{Captured reference 'ref_countable_ref' to uncounted type is unsafe [webkit.UncountedLambdaCapturesChecker]}}
   auto foo3 = [&](){ ref_countable_ref.method(); };
   // expected-warning@-1{{Implicitly captured reference 'ref_countable_ref' to uncounted type is unsafe [webkit.UncountedLambdaCapturesChecker]}}
   auto foo4 = [=](){ ref_countable_ref.constMethod(); };
-  // expected-warning@-1{{Implicitly captured reference 'ref_countable_ref' to uncounted type is unsafe [webkit.UncountedLambdaCapturesChecker]}}
 
   call(foo1);
   call(foo2);
@@ -407,3 +405,14 @@ void lambda_converted_to_function(RefCountable* obj)
     // expected-warning@-1{{Implicitly captured raw-pointer 'obj' to uncounted type is unsafe [webkit.UncountedLambdaCapturesChecker]}}
   });
 }
+
+void capture_copy_in_lambda(CheckedObj& checked) {
+  callFunctionOpaque([checked]() mutable {
+    checked.method();
+  });
+  auto* ptr = &checked;
+  callFunctionOpaque([ptr]() mutable {
+    // expected-warning@-1{{Captured raw-pointer 'ptr' to uncounted type is unsafe [webkit.UncountedLambdaCapturesChecker]}}
+    ptr->method();
+  });
+}