[analyzer] Fix QTimer::singleShot NewDeleteLeaks false positive

[mkmvzlb]

Summary

Fixes #39713

[steakhal]

Good job. Looks good to me.
This is pretty much analogous to D27717. The same reasoning applies.
Thanks for the patch. Should I commit this on your behalf?

[mkmvzlb]

In D150552#4345391, @steakhal wrote:

Thanks for the patch. Should I commit this on your behalf?

Thanks for reviewing and - in advance - for commit: --author "Michael Klein <[e-mail]>"

[steakhal]

And I managed to make a typo in the commit message :D
Closed by 3b6a368d763e812024ca6ba4024855603f693291

clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp

if (FName == "postEvent" &&
     return true;
   }
 
   if (FName == "connectImpl" &&
       FD->getQualifiedNameAsString() == "QObject::connectImpl") {
     return true;
   }
 
+  if (FName == "singleShotImpl" &&
+      FD->getQualifiedNameAsString() == "QTimer::singleShotImpl") {
+    return true;
+  }
+
   // Handle cases where we know a buffer's /address/ can escape.
   // Note that the above checks handle some special cases where we know that
   // even though the address escapes, it's still our responsibility to free the
   // buffer.
   if (Call->argumentsMayEscape())
     return true;
 
   // Otherwise, assume that the function does not free memory.

clang/test/Analysis/Inputs/qt-simulator.h

 #pragma clang system_header
 
 namespace QtPrivate {
 struct QSlotObjectBase {};
 }
 
 namespace Qt {
 enum ConnectionType {};
+enum TimerType {};
 }
 
 struct QMetaObject {
   struct Connection {};
 };
 
 struct QObject {
   static QMetaObject::Connection connectImpl(const QObject *, void **,

 };
 
 struct QCoreApplication : public QObject {
   static void postEvent(QObject *receiver, QEvent *event);
   static QCoreApplication *instance();
 };
 
 struct QApplication : public QCoreApplication {};
+
+struct QTimer {
+  static void singleShotImpl(int, Qt::TimerType, const QObject *,
+                             QtPrivate::QSlotObjectBase *);
+};

clang/test/Analysis/qt_malloc.cpp

void send(QObject *obj)
   QApplication::postEvent(obj, e4);
 }
 
 void connect(QObject *obj) {
   obj->connectImpl(nullptr, nullptr, nullptr, nullptr,
                    new QtPrivate::QSlotObjectBase(), (Qt::ConnectionType)0,
                    nullptr, nullptr);
 }
+
+void singleShot(QTimer *timer) {
+  timer->singleShotImpl(0, (Qt::TimerType)0, nullptr,
+                        new QtPrivate::QSlotObjectBase());
+}