Clean-up warnings in corelib/thread tests

Fixed the following warnings:

 - empty expression statement has no effect; remove unnecessary ';'
   to silence this warning
 - zero as null pointer constant
 - no previous extern declaration for non-static variable
 - use of old-style cast
 - integer conversion warnings

Change-Id: Ieb31b127ce8e3b543aaf88a8e8fc463dcc8bc4e3
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

16 files changed, 122 insertions, 122 deletions

diff --git a/tests/auto/corelib/thread/qatomicpointer/tst_qatomicpointer.cpp b/tests/auto/corelib/thread/qatomicpointer/tst_qatomicpointer.cpp
index 4361609442..c2aff5a70a 100644
--- a/tests/auto/corelib/thread/qatomicpointer/tst_qatomicpointer.cpp
+++ b/tests/auto/corelib/thread/qatomicpointer/tst_qatomicpointer.cpp
@@ -73,7 +73,7 @@ void tst_QAtomicPointer::warningFreeHelper()
 {
     qFatal("This code is bogus, and shouldn't be run. We're looking for compiler warnings only.");
 
-    QBasicAtomicPointer<WFHC> p = Q_BASIC_ATOMIC_INITIALIZER(0);
+    QBasicAtomicPointer<WFHC> p = Q_BASIC_ATOMIC_INITIALIZER(nullptr);
 
     p.loadRelaxed()->bar();
 
@@ -645,8 +645,8 @@ void tst_QAtomicPointer::forwardDeclared()
     // this is just a compilation test
     QAtomicPointer<ForwardDeclared> ptr;
     ContainsForwardDeclared cfd;
-    Q_UNUSED(ptr);
-    Q_UNUSED(cfd);
+    Q_UNUSED(ptr)
+    Q_UNUSED(cfd)
     QVERIFY(true);
 }
 
@@ -661,7 +661,7 @@ template <typename T> static void operators_helper()
     {
         // Test that QBasicAtomicPointer also has operator= and cast operators
         // We've been using them for QAtomicPointer<T> elsewhere
-        QBasicAtomicPointer<T> atomic = Q_BASIC_ATOMIC_INITIALIZER(0);
+        QBasicAtomicPointer<T> atomic = Q_BASIC_ATOMIC_INITIALIZER(nullptr);
         atomic = one;
         QCOMPARE(Ptr(atomic), one);
     }
diff --git a/tests/auto/corelib/thread/qfuture/tst_qfuture.cpp b/tests/auto/corelib/thread/qfuture/tst_qfuture.cpp
index 3616500af8..df8948f767 100644
--- a/tests/auto/corelib/thread/qfuture/tst_qfuture.cpp
+++ b/tests/auto/corelib/thread/qfuture/tst_qfuture.cpp
@@ -1182,13 +1182,13 @@ void tst_QFuture::iterators()
         QVERIFY(c2 != c1);
 
         int x1 = *i1;
-        Q_UNUSED(x1);
+        Q_UNUSED(x1)
         int x2 = *i2;
-        Q_UNUSED(x2);
+        Q_UNUSED(x2)
         int y1 = *c1;
-        Q_UNUSED(y1);
+        Q_UNUSED(y1)
         int y2 = *c2;
-        Q_UNUSED(y2);
+        Q_UNUSED(y2)
     }
 
     {
@@ -1240,10 +1240,10 @@ void tst_QFuture::iterators()
         QCOMPARE(x1, y1);
         QCOMPARE(x2, y2);
 
-        int i1Size = i1->size();
-        int i2Size = i2->size();
-        int c1Size = c1->size();
-        int c2Size = c2->size();
+        auto i1Size = i1->size();
+        auto i2Size = i2->size();
+        auto c1Size = c1->size();
+        auto c2Size = c2->size();
 
         QCOMPARE(i1Size, c1Size);
         QCOMPARE(i2Size, c2Size);
@@ -1688,7 +1688,7 @@ void tst_QFuture::exceptions()
         bool caught = false;
         try {
             foreach (int e, f.results()) {
-                Q_UNUSED(e);
+                Q_UNUSED(e)
                 QFAIL("did not get exception");
             }
         } catch (QException &) {
@@ -1755,7 +1755,7 @@ void tst_QFuture::nestedExceptions()
 {
     try {
         MyClass m;
-        Q_UNUSED(m);
+        Q_UNUSED(m)
         throw 0;
     } catch (int) {}
 
@@ -1783,7 +1783,7 @@ void tst_QFuture::nonGlobalThreadPool()
         void run() override
         {
             const int ms = 100 + (QRandomGenerator::global()->bounded(100) - 100/2);
-            QThread::msleep(ms);
+            QThread::msleep(ulong(ms));
             reportResult(Answer);
             reportFinished();
         }
@@ -2913,7 +2913,7 @@ void tst_QFuture::testSingleResult(const std::vector<int> &v)
 template<class T>
 void tst_QFuture::testSingleResult(const T &unknown)
 {
-    Q_UNUSED(unknown);
+    Q_UNUSED(unknown)
 }
 
 
diff --git a/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp b/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
index e83ea07dd4..e5952e7c8d 100644
--- a/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
+++ b/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
@@ -114,9 +114,9 @@ void mapSleeper(int &)
     QTest::qSleep(100);
 }
 
-QSet<int> progressValues;
-QSet<QString> progressTexts;
-QMutex mutex;
+static QSet<int> progressValues;
+static QSet<QString> progressTexts;
+static QMutex mutex;
 class ProgressObject : public QObject
 {
 Q_OBJECT
@@ -191,7 +191,7 @@ class CancelObject : public QObject
 Q_OBJECT
 public:
     bool wasCanceled;
-    CancelObject() : wasCanceled(false) {};
+    CancelObject() : wasCanceled(false) {}
 public slots:
     void cancel();
 };
diff --git a/tests/auto/corelib/thread/qmutex/tst_qmutex.cpp b/tests/auto/corelib/thread/qmutex/tst_qmutex.cpp
index a2e71c0a24..88ecee7999 100644
--- a/tests/auto/corelib/thread/qmutex/tst_qmutex.cpp
+++ b/tests/auto/corelib/thread/qmutex/tst_qmutex.cpp
@@ -46,7 +46,7 @@ public:
         Milliseconds,
         Seconds,
     };
-    Q_ENUM(TimeUnit);
+    Q_ENUM(TimeUnit)
 
 private slots:
     void convertToMilliseconds_data();
@@ -68,11 +68,11 @@ private slots:
 
 static const int iterations = 100;
 
-QAtomicInt lockCount(0);
-QMutex normalMutex;
-QRecursiveMutex recursiveMutex;
-QSemaphore testsTurn;
-QSemaphore threadsTurn;
+static QAtomicInt lockCount(0);
+static QMutex normalMutex;
+static QRecursiveMutex recursiveMutex;
+static QSemaphore testsTurn;
+static QSemaphore threadsTurn;
 
 /*
     Depending on the OS, tryWaits may return early than expected because of the
@@ -1288,14 +1288,14 @@ public:
         quint64 i = 0;
         while (t.elapsed() < one_minute) {
             i++;
-            uint nb = (i * 9 + lockCount.loadRelaxed() * 13) % threadCount;
+            uint nb = (i * 9 + uint(lockCount.loadRelaxed()) * 13) % threadCount;
             QMutexLocker locker(&mutex[nb]);
             if (sentinel[nb].loadRelaxed()) errorCount.ref();
             if (sentinel[nb].fetchAndAddRelaxed(5)) errorCount.ref();
             if (!sentinel[nb].testAndSetRelaxed(5, 0)) errorCount.ref();
             if (sentinel[nb].loadRelaxed()) errorCount.ref();
             lockCount.ref();
-            nb = (nb * 17 + i * 5 + lockCount.loadRelaxed() * 3) % threadCount;
+            nb = (nb * 17 + i * 5 + uint(lockCount.loadRelaxed()) * 3) % threadCount;
             if (mutex[nb].tryLock()) {
                 if (sentinel[nb].loadRelaxed()) errorCount.ref();
                 if (sentinel[nb].fetchAndAddRelaxed(16)) errorCount.ref();
@@ -1304,7 +1304,7 @@ public:
                 lockCount.ref();
                 mutex[nb].unlock();
             }
-            nb = (nb * 15 + i * 47 + lockCount.loadRelaxed() * 31) % threadCount;
+            nb = (nb * 15 + i * 47 + uint(lockCount.loadRelaxed()) * 31) % threadCount;
             if (mutex[nb].tryLock(2)) {
                 if (sentinel[nb].loadRelaxed()) errorCount.ref();
                 if (sentinel[nb].fetchAndAddRelaxed(53)) errorCount.ref();
diff --git a/tests/auto/corelib/thread/qmutexlocker/tst_qmutexlocker.cpp b/tests/auto/corelib/thread/qmutexlocker/tst_qmutexlocker.cpp
index 46cdd8073e..30268890ed 100644
--- a/tests/auto/corelib/thread/qmutexlocker/tst_qmutexlocker.cpp
+++ b/tests/auto/corelib/thread/qmutexlocker/tst_qmutexlocker.cpp
@@ -110,7 +110,7 @@ void tst_QMutexLocker::scopeTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 
@@ -157,7 +157,7 @@ void tst_QMutexLocker::unlockAndRelockTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 void tst_QMutexLocker::lockerStateTest()
@@ -197,7 +197,7 @@ void tst_QMutexLocker::lockerStateTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 QTEST_MAIN(tst_QMutexLocker)
diff --git a/tests/auto/corelib/thread/qpromise/tst_qpromise.cpp b/tests/auto/corelib/thread/qpromise/tst_qpromise.cpp
index 82a359451d..74a3059699 100644
--- a/tests/auto/corelib/thread/qpromise/tst_qpromise.cpp
+++ b/tests/auto/corelib/thread/qpromise/tst_qpromise.cpp
@@ -77,7 +77,7 @@ private slots:
 
 struct TrivialType { int field = 0; };
 struct CopyOnlyType {
-    Q_DISABLE_MOVE(CopyOnlyType);
+    Q_DISABLE_MOVE(CopyOnlyType)
     CopyOnlyType() = default;
     CopyOnlyType(const CopyOnlyType &) = default;
     CopyOnlyType& operator=(const CopyOnlyType &) = default;
@@ -86,7 +86,7 @@ struct CopyOnlyType {
     int field = 0;
 };
 struct MoveOnlyType {
-    Q_DISABLE_COPY(MoveOnlyType);
+    Q_DISABLE_COPY(MoveOnlyType)
     MoveOnlyType() = default;
     MoveOnlyType(MoveOnlyType &&) = default;
     MoveOnlyType& operator=(MoveOnlyType &&) = default;
diff --git a/tests/auto/corelib/thread/qreadlocker/tst_qreadlocker.cpp b/tests/auto/corelib/thread/qreadlocker/tst_qreadlocker.cpp
index 241f064a21..8f0b182d05 100644
--- a/tests/auto/corelib/thread/qreadlocker/tst_qreadlocker.cpp
+++ b/tests/auto/corelib/thread/qreadlocker/tst_qreadlocker.cpp
@@ -109,7 +109,7 @@ void tst_QReadLocker::scopeTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 
@@ -156,7 +156,7 @@ void tst_QReadLocker::unlockAndRelockTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 void tst_QReadLocker::lockerStateTest()
@@ -196,7 +196,7 @@ void tst_QReadLocker::lockerStateTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 QTEST_MAIN(tst_QReadLocker)
diff --git a/tests/auto/corelib/thread/qreadwritelock/tst_qreadwritelock.cpp b/tests/auto/corelib/thread/qreadwritelock/tst_qreadwritelock.cpp
index 76e50eee1b..12bc4ba6af 100644
--- a/tests/auto/corelib/thread/qreadwritelock/tst_qreadwritelock.cpp
+++ b/tests/auto/corelib/thread/qreadwritelock/tst_qreadwritelock.cpp
@@ -184,10 +184,10 @@ void tst_QReadWriteLock::readWriteLockUnlockLoop()
 
 }
 
-QAtomicInt lockCount(0);
-QReadWriteLock readWriteLock;
-QSemaphore testsTurn;
-QSemaphore threadsTurn;
+static QAtomicInt lockCount(0);
+static QReadWriteLock readWriteLock;
+static QSemaphore testsTurn;
+static QSemaphore threadsTurn;
 
 
 void tst_QReadWriteLock::tryReadLock()
@@ -403,8 +403,8 @@ void tst_QReadWriteLock::tryWriteLock()
     }
 }
 
-bool threadDone;
-QAtomicInt release;
+static bool threadDone;
+static QAtomicInt release;
 
 /*
     write-lock
@@ -511,9 +511,9 @@ public:
         while (t.elapsed()<runTime)  {
             testRwlock.lockForRead();
             if(print) printf("reading\n");
-            if (holdTime) msleep(holdTime);
+            if (holdTime) msleep(ulong(holdTime));
             testRwlock.unlock();
-            if (waitTime) msleep(waitTime);
+            if (waitTime) msleep(ulong(waitTime));
         }
     }
 };
@@ -547,14 +547,14 @@ public:
         while (t.elapsed() < runTime)  {
             testRwlock.lockForWrite();
             if (print) printf(".");
-            if (holdTime) msleep(holdTime);
+            if (holdTime) msleep(ulong(holdTime));
             testRwlock.unlock();
-            if (waitTime) msleep(waitTime);
+            if (waitTime) msleep(ulong(waitTime));
         }
     }
 };
 
-volatile int count=0;
+static volatile int count = 0;
 
 /*
     for(runTime msecs)
@@ -594,7 +594,7 @@ public:
             }
             count=0;
             testRwlock.unlock();
-            msleep(waitTime);
+            msleep(ulong(waitTime));
         }
     }
 };
@@ -626,7 +626,7 @@ public:
             if(count)
                 qFatal("Non-zero count at Read! (%d)",count );
             testRwlock.unlock();
-            msleep(waitTime);
+            msleep(ulong(waitTime));
         }
     }
 };
diff --git a/tests/auto/corelib/thread/qresultstore/tst_qresultstore.cpp b/tests/auto/corelib/thread/qresultstore/tst_qresultstore.cpp
index 6e0bbda2c2..dff599180c 100644
--- a/tests/auto/corelib/thread/qresultstore/tst_qresultstore.cpp
+++ b/tests/auto/corelib/thread/qresultstore/tst_qresultstore.cpp
@@ -535,7 +535,7 @@ void tst_QtConcurrentResultStore::pendingResultsDoNotLeak_data()
 void tst_QtConcurrentResultStore::pendingResultsDoNotLeak()
 {
     QFETCH(bool, filterMode);
-    CountedObject::LeakChecker leakChecker; Q_UNUSED(leakChecker);
+    CountedObject::LeakChecker leakChecker; Q_UNUSED(leakChecker)
 
     ResultStoreCountedObject store;
     store.setFilterMode(filterMode);
diff --git a/tests/auto/corelib/thread/qsemaphore/tst_qsemaphore.cpp b/tests/auto/corelib/thread/qsemaphore/tst_qsemaphore.cpp
index f556e402e3..bce0088463 100644
--- a/tests/auto/corelib/thread/qsemaphore/tst_qsemaphore.cpp
+++ b/tests/auto/corelib/thread/qsemaphore/tst_qsemaphore.cpp
@@ -106,7 +106,7 @@ void tst_QSemaphore::acquire()
         QVERIFY(t2.wait(4000));
 
         delete semaphore;
-        semaphore = 0;
+        semaphore = nullptr;
     }
 
     // old incrementN() test
@@ -126,7 +126,7 @@ void tst_QSemaphore::acquire()
         QVERIFY(t2.wait(4000));
 
         delete semaphore;
-        semaphore = 0;
+        semaphore = nullptr;
     }
 
     QSemaphore semaphore;
@@ -177,7 +177,7 @@ void tst_QSemaphore::multiRelease()
     // wait for all threads to reach the sem.acquire() and then
     // release them all
     QTest::qSleep(1);
-    sem.release(threads.size());
+    sem.release(int(threads.size()));
 
     for (Thread *&t : threads)
         t->wait();
@@ -323,69 +323,69 @@ void tst_QSemaphore::tryAcquireWithTimeout()
     QCOMPARE(semaphore.available(), 1);
     time.start();
     QVERIFY(!semaphore.tryAcquire(2, timeout));
-    FUZZYCOMPARE(time.elapsed(), timeout);
+    FUZZYCOMPARE(int(time.elapsed()), timeout);
     QCOMPARE(semaphore.available(), 1);
 
     semaphore.release();
     QCOMPARE(semaphore.available(), 2);
     time.start();
     QVERIFY(!semaphore.tryAcquire(3, timeout));
-    FUZZYCOMPARE(time.elapsed(), timeout);
+    FUZZYCOMPARE(int(time.elapsed()), timeout);
     QCOMPARE(semaphore.available(), 2);
 
     semaphore.release(10);
     QCOMPARE(semaphore.available(), 12);
     time.start();
     QVERIFY(!semaphore.tryAcquire(100, timeout));
-    FUZZYCOMPARE(time.elapsed(), timeout);
+    FUZZYCOMPARE(int(time.elapsed()), timeout);
     QCOMPARE(semaphore.available(), 12);
 
     semaphore.release(10);
     QCOMPARE(semaphore.available(), 22);
     time.start();
     QVERIFY(!semaphore.tryAcquire(100, timeout));
-    FUZZYCOMPARE(time.elapsed(), timeout);
+    FUZZYCOMPARE(int(time.elapsed()), timeout);
     QCOMPARE(semaphore.available(), 22);
 
     time.start();
     QVERIFY(semaphore.tryAcquire(1, timeout));
-    FUZZYCOMPARE(time.elapsed(), 0);
+    FUZZYCOMPARE(int(time.elapsed()), 0);
     QCOMPARE(semaphore.available(), 21);
 
     time.start();
     QVERIFY(semaphore.tryAcquire(1, timeout));
-    FUZZYCOMPARE(time.elapsed(), 0);
+    FUZZYCOMPARE(int(time.elapsed()), 0);
     QCOMPARE(semaphore.available(), 20);
 
     time.start();
     QVERIFY(semaphore.tryAcquire(10, timeout));
-    FUZZYCOMPARE(time.elapsed(), 0);
+    FUZZYCOMPARE(int(time.elapsed()), 0);
     QCOMPARE(semaphore.available(), 10);
 
     time.start();
     QVERIFY(semaphore.tryAcquire(10, timeout));
-    FUZZYCOMPARE(time.elapsed(), 0);
+    FUZZYCOMPARE(int(time.elapsed()), 0);
     QCOMPARE(semaphore.available(), 0);
 
     // should not be able to acquire more
     time.start();
     QVERIFY(!semaphore.tryAcquire(1, timeout));
-    FUZZYCOMPARE(time.elapsed(), timeout);
+    FUZZYCOMPARE(int(time.elapsed()), timeout);
     QCOMPARE(semaphore.available(), 0);
 
     time.start();
     QVERIFY(!semaphore.tryAcquire(1, timeout));
-    FUZZYCOMPARE(time.elapsed(), timeout);
+    FUZZYCOMPARE(int(time.elapsed()), timeout);
     QCOMPARE(semaphore.available(), 0);
 
     time.start();
     QVERIFY(!semaphore.tryAcquire(10, timeout));
-    FUZZYCOMPARE(time.elapsed(), timeout);
+    FUZZYCOMPARE(int(time.elapsed()), timeout);
     QCOMPARE(semaphore.available(), 0);
 
     time.start();
     QVERIFY(!semaphore.tryAcquire(10, timeout));
-    FUZZYCOMPARE(time.elapsed(), timeout);
+    FUZZYCOMPARE(int(time.elapsed()), timeout);
     QCOMPARE(semaphore.available(), 0);
 
 #undef FUZZYCOMPARE
@@ -481,7 +481,7 @@ const char alphabet[] = "ACGTH";
 const int AlphabetSize = sizeof(alphabet) - 1;
 
 const int BufferSize = 4096; // GCD of BufferSize and alphabet size must be 1
-char buffer[BufferSize];
+static char buffer[BufferSize];
 
 const int ProducerChunkSize = 3;
 const int ConsumerChunkSize = 7;
@@ -491,8 +491,8 @@ const int Multiplier = 10;
 // ProducerChunkSize, ConsumerChunkSize, and BufferSize
 const int DataSize = ProducerChunkSize * ConsumerChunkSize * BufferSize * Multiplier;
 
-QSemaphore freeSpace(BufferSize);
-QSemaphore usedSpace;
+static QSemaphore freeSpace(BufferSize);
+static QSemaphore usedSpace;
 
 class Producer : public QThread
 {
diff --git a/tests/auto/corelib/thread/qthread/tst_qthread.cpp b/tests/auto/corelib/thread/qthread/tst_qthread.cpp
index 1e8380fbba..3f5b255be4 100644
--- a/tests/auto/corelib/thread/qthread/tst_qthread.cpp
+++ b/tests/auto/corelib/thread/qthread/tst_qthread.cpp
@@ -241,9 +241,9 @@ public:
     enum SleepType { Second, Millisecond, Microsecond };
 
     SleepType sleepType;
-    int interval;
+    ulong interval;
 
-    int elapsed; // result, in *MILLISECONDS*
+    qint64 elapsed; // result, in *MILLISECONDS*
 
     void run() override
     {
@@ -272,25 +272,25 @@ public:
 void tst_QThread::currentThreadId()
 {
     Current_Thread thread;
-    thread.id = 0;
-    thread.thread = 0;
+    thread.id = nullptr;
+    thread.thread = nullptr;
     thread.start();
     QVERIFY(thread.wait(five_minutes));
-    QVERIFY(thread.id != 0);
+    QVERIFY(thread.id != nullptr);
     QVERIFY(thread.id != QThread::currentThreadId());
 }
 
 void tst_QThread::currentThread()
 {
-    QVERIFY(QThread::currentThread() != 0);
+    QVERIFY(QThread::currentThread() != nullptr);
     QCOMPARE(QThread::currentThread(), thread());
 
     Current_Thread thread;
-    thread.id = 0;
-    thread.thread = 0;
+    thread.id = nullptr;
+    thread.thread = nullptr;
     thread.start();
     QVERIFY(thread.wait(five_minutes));
-    QCOMPARE(thread.thread, (QThread *)&thread);
+    QCOMPARE(thread.thread, static_cast<QThread *>(&thread));
 }
 
 void tst_QThread::idealThreadCount()
@@ -646,7 +646,7 @@ void noop(void*) { }
 class NativeThreadWrapper
 {
 public:
-    NativeThreadWrapper() : qthread(0), waitForStop(false) {}
+    NativeThreadWrapper() : qthread(nullptr), waitForStop(false) {}
     void start(FunctionPointer functionPointer = noop, void *data = nullptr);
     void startAndWait(FunctionPointer functionPointer = noop, void *data = nullptr);
     void join();
@@ -672,8 +672,8 @@ void NativeThreadWrapper::start(FunctionPointer functionPointer, void *data)
     this->functionPointer = functionPointer;
     this->data = data;
 #if defined Q_OS_UNIX
-    const int state = pthread_create(&nativeThreadHandle, 0, NativeThreadWrapper::runUnix, this);
-    Q_UNUSED(state);
+    const int state = pthread_create(&nativeThreadHandle, nullptr, NativeThreadWrapper::runUnix, this);
+    Q_UNUSED(state)
 #elif defined Q_OS_WIN
     unsigned thrdid = 0;
     nativeThreadHandle = (Qt::HANDLE) _beginthreadex(NULL, 0, NativeThreadWrapper::runWin, this, 0, &thrdid);
@@ -690,7 +690,7 @@ void NativeThreadWrapper::startAndWait(FunctionPointer functionPointer, void *da
 void NativeThreadWrapper::join()
 {
 #if defined Q_OS_UNIX
-    pthread_join(nativeThreadHandle, 0);
+    pthread_join(nativeThreadHandle, nullptr);
 #elif defined Q_OS_WIN
     WaitForSingleObjectEx(nativeThreadHandle, INFINITE, FALSE);
     CloseHandle(nativeThreadHandle);
@@ -720,7 +720,7 @@ void *NativeThreadWrapper::runUnix(void *that)
             nativeThreadWrapper->stopCondition.wait(lock.mutex());
     }
 
-    return 0;
+    return nullptr;
 }
 
 unsigned WIN_FIX_STDCALL NativeThreadWrapper::runWin(void *data)
@@ -736,12 +736,12 @@ void NativeThreadWrapper::stop()
     stopCondition.wakeOne();
 }
 
-bool threadAdoptedOk = false;
-QThread *mainThread;
+static bool threadAdoptedOk = false;
+static QThread *mainThread;
 void testNativeThreadAdoption(void *)
 {
-    threadAdoptedOk = (QThread::currentThreadId() != 0
-                       && QThread::currentThread() != 0
+    threadAdoptedOk = (QThread::currentThreadId() != nullptr
+                       && QThread::currentThread() != nullptr
                        && QThread::currentThread() != mainThread);
 }
 void tst_QThread::nativeThreadAdoption()
@@ -769,7 +769,7 @@ void adoptedThreadAffinityFunction(void *arg)
 
 void tst_QThread::adoptedThreadAffinity()
 {
-    QThread *affinity[2] = { 0, 0 };
+    QThread *affinity[2] = { nullptr, nullptr };
 
     NativeThreadWrapper thread;
     thread.startAndWait(adoptedThreadAffinityFunction, affinity);
@@ -1142,7 +1142,7 @@ void tst_QThread::startFinishRace()
         void run() override
         {
             i--;
-            if (!i) disconnect(this, SIGNAL(finished()), 0, 0);
+            if (!i) disconnect(this, SIGNAL(finished()), nullptr, nullptr);
         }
         int i;
     };
diff --git a/tests/auto/corelib/thread/qthreadonce/tst_qthreadonce.cpp b/tests/auto/corelib/thread/qthreadonce/tst_qthreadonce.cpp
index 6859a55725..76974fc5fb 100644
--- a/tests/auto/corelib/thread/qthreadonce/tst_qthreadonce.cpp
+++ b/tests/auto/corelib/thread/qthreadonce/tst_qthreadonce.cpp
@@ -112,7 +112,7 @@ void tst_QThreadOnce::sameThread()
     QCOMPARE(controlVariable, 1);
 
     static QSingleton<SingletonObject> s;
-    QTEST((int)s->val.loadRelaxed(), "expectedValue");
+    QTEST(int(s->val.loadRelaxed()), "expectedValue");
     s->val.ref();
 
     QCOMPARE(SingletonObject::runCount, 1);
@@ -145,7 +145,7 @@ void tst_QThreadOnce::multipleThreads()
     delete parent;
 
     QCOMPARE(controlVariable, 1);
-    QCOMPARE((int)IncrementThread::runCount.loadRelaxed(), NumberOfThreads);
+    QCOMPARE(int(IncrementThread::runCount.loadRelaxed()), NumberOfThreads);
     QCOMPARE(SingletonObject::runCount, 1);
 }
 
diff --git a/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp b/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
index e6db963c7b..fb563609e2 100644
--- a/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
+++ b/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
@@ -119,7 +119,7 @@ tst_QThreadPool::~tst_QThreadPool()
     tst_QThreadPool::functionTestMutex = nullptr;
 }
 
-int testFunctionCount;
+static int testFunctionCount;
 
 void sleepTestFunction()
 {
@@ -225,7 +225,7 @@ void tst_QThreadPool::waitcomplete()
     QCOMPARE(testFunctionCount, runs);
 }
 
-QAtomicInt ran; // bool
+static QAtomicInt ran; // bool
 class TestTask : public QRunnable
 {
 public:
@@ -253,7 +253,7 @@ void tst_QThreadPool::singleton()
     QTRY_VERIFY(ran.loadRelaxed());
 }
 
-QAtomicInt *value = 0;
+static QAtomicInt *value = nullptr;
 class IntAccessor : public QRunnable
 {
 public:
@@ -278,11 +278,11 @@ void tst_QThreadPool::destruction()
     threadManager->start(new IntAccessor());
     delete threadManager;
     delete value;
-    value = 0;
+    value = nullptr;
 }
 
-QSemaphore threadRecyclingSemaphore;
-QThread *recycledThread = nullptr;
+static QSemaphore threadRecyclingSemaphore;
+static QThread *recycledThread = nullptr;
 
 class ThreadRecorderTask : public QRunnable
 {
@@ -328,7 +328,7 @@ public:
     QSemaphore semaphore;
 
     ExpiryTimeoutTask()
-        : thread(0), runCount(0)
+        : thread(nullptr), runCount(0)
     {
         setAutoDelete(false);
     }
@@ -720,7 +720,7 @@ void tst_QThreadPool::reserveAndStart() // QTBUG-21051
     threadpool->setMaxThreadCount(savedLimit);
 }
 
-QAtomicInt count;
+static QAtomicInt count;
 class CountingRunnable : public QRunnable
 {
 public:
@@ -772,9 +772,9 @@ void tst_QThreadPool::tryStart()
     QCOMPARE(count.loadRelaxed(), threadPool.maxThreadCount());
 }
 
-QMutex mutex;
-QAtomicInt activeThreads;
-QAtomicInt peakActiveThreads;
+static QMutex mutex;
+static QAtomicInt activeThreads;
+static QAtomicInt peakActiveThreads;
 void tst_QThreadPool::tryStartPeakThreadCount()
 {
     class CounterTask : public QRunnable
@@ -868,7 +868,7 @@ void tst_QThreadPool::priorityStart()
         Runner(QAtomicPointer<QRunnable> &ptr) : ptr(ptr) {}
         void run() override
         {
-            ptr.testAndSetRelaxed(0, this);
+            ptr.testAndSetRelaxed(nullptr, this);
         }
     };
 
@@ -1017,7 +1017,7 @@ void tst_QThreadPool::tryTake()
         explicit BlockingRunnable(QSemaphore &s, QSemaphore &started, QAtomicInt &c, QAtomicInt &r)
             : sem(s), startedThreads(started), dtorCounter(c), runCounter(r) {}
 
-        ~BlockingRunnable()
+        ~BlockingRunnable() override
         {
             dtorCounter.fetchAndAddRelaxed(1);
         }
diff --git a/tests/auto/corelib/thread/qthreadstorage/tst_qthreadstorage.cpp b/tests/auto/corelib/thread/qthreadstorage/tst_qthreadstorage.cpp
index ab1dd677e9..dfb4953c9d 100644
--- a/tests/auto/corelib/thread/qthreadstorage/tst_qthreadstorage.cpp
+++ b/tests/auto/corelib/thread/qthreadstorage/tst_qthreadstorage.cpp
@@ -76,7 +76,7 @@ void tst_QThreadStorage::hasLocalData()
     QVERIFY(!pointers.hasLocalData());
     pointers.setLocalData(new Pointer);
     QVERIFY(pointers.hasLocalData());
-    pointers.setLocalData(0);
+    pointers.setLocalData(nullptr);
     QVERIFY(!pointers.hasLocalData());
 }
 
@@ -88,8 +88,8 @@ void tst_QThreadStorage::localData()
     pointers.setLocalData(p);
     QVERIFY(pointers.hasLocalData());
     QCOMPARE(pointers.localData(), p);
-    pointers.setLocalData(0);
-    QCOMPARE(pointers.localData(), (Pointer *)0);
+    pointers.setLocalData(nullptr);
+    QCOMPARE(pointers.localData(), nullptr);
     QVERIFY(!pointers.hasLocalData());
 }
 
@@ -102,8 +102,8 @@ void tst_QThreadStorage::localData_const()
     pointers.setLocalData(p);
     QVERIFY(pointers.hasLocalData());
     QCOMPARE(const_pointers.localData(), p);
-    pointers.setLocalData(0);
-    QCOMPARE(const_pointers.localData(), (Pointer *)0);
+    pointers.setLocalData(nullptr);
+    QCOMPARE(const_pointers.localData(), nullptr);
     QVERIFY(!pointers.hasLocalData());
 }
 
@@ -113,7 +113,7 @@ void tst_QThreadStorage::setLocalData()
     QVERIFY(!pointers.hasLocalData());
     pointers.setLocalData(new Pointer);
     QVERIFY(pointers.hasLocalData());
-    pointers.setLocalData(0);
+    pointers.setLocalData(nullptr);
     QVERIFY(!pointers.hasLocalData());
 }
 
@@ -157,7 +157,7 @@ void tst_QThreadStorage::autoDelete()
     QCOMPARE(Pointer::count, c);
 }
 
-bool threadStorageOk;
+static bool threadStorageOk;
 void testAdoptedThreadStorageWin(void *p)
 {
     QThreadStorage<Pointer *>  *pointers = reinterpret_cast<QThreadStorage<Pointer *> *>(p);
@@ -183,7 +183,7 @@ void testAdoptedThreadStorageWin(void *p)
 void *testAdoptedThreadStorageUnix(void *pointers)
 {
     testAdoptedThreadStorageWin(pointers);
-    return 0;
+    return nullptr;
 }
 void tst_QThreadStorage::adoptedThreads()
 {
@@ -194,9 +194,9 @@ void tst_QThreadStorage::adoptedThreads()
     {
 #ifdef Q_OS_UNIX
         pthread_t thread;
-        const int state = pthread_create(&thread, 0, testAdoptedThreadStorageUnix, &pointers);
+        const int state = pthread_create(&thread, nullptr, testAdoptedThreadStorageUnix, &pointers);
         QCOMPARE(state, 0);
-        pthread_join(thread, 0);
+        pthread_join(thread, nullptr);
 #elif defined Q_OS_WIN
         HANDLE thread;
         thread = (HANDLE)_beginthread(testAdoptedThreadStorageWin, 0, &pointers);
@@ -212,7 +212,7 @@ void tst_QThreadStorage::adoptedThreads()
     QTRY_COMPARE(Pointer::count, c);
 }
 
-QBasicAtomicInt cleanupOrder = Q_BASIC_ATOMIC_INITIALIZER(0);
+static QBasicAtomicInt cleanupOrder = Q_BASIC_ATOMIC_INITIALIZER(0);
 
 class First
 {
diff --git a/tests/auto/corelib/thread/qwaitcondition/tst_qwaitcondition.cpp b/tests/auto/corelib/thread/qwaitcondition/tst_qwaitcondition.cpp
index 3fcac48788..9706f34236 100644
--- a/tests/auto/corelib/thread/qwaitcondition/tst_qwaitcondition.cpp
+++ b/tests/auto/corelib/thread/qwaitcondition/tst_qwaitcondition.cpp
@@ -95,7 +95,7 @@ public:
     QWaitCondition *cond;
 
     inline wait_QMutex_Thread_2()
-    : mutex(0), cond(0)
+    : mutex(nullptr), cond(nullptr)
     { }
 
     void run() override
@@ -134,7 +134,7 @@ public:
     QWaitCondition *cond;
 
     inline wait_QReadWriteLock_Thread_2()
-    : readWriteLock(0), cond(0)
+    : readWriteLock(nullptr), cond(nullptr)
     { }
 
     void run() override
@@ -392,7 +392,7 @@ public:
     QWaitCondition *cond;
 
     inline wake_Thread()
-    : mutex(0), cond(0)
+    : mutex(nullptr), cond(nullptr)
     { }
 
     static inline void sleep(ulong s)
@@ -424,7 +424,7 @@ public:
     QWaitCondition *cond;
 
     inline wake_Thread_2()
-    : readWriteLock(0), cond(0)
+    : readWriteLock(nullptr), cond(nullptr)
     { }
 
     static inline void sleep(ulong s)
diff --git a/tests/auto/corelib/thread/qwritelocker/tst_qwritelocker.cpp b/tests/auto/corelib/thread/qwritelocker/tst_qwritelocker.cpp
index 3dc3c37961..fd0f2d8d7e 100644
--- a/tests/auto/corelib/thread/qwritelocker/tst_qwritelocker.cpp
+++ b/tests/auto/corelib/thread/qwritelocker/tst_qwritelocker.cpp
@@ -109,7 +109,7 @@ void tst_QWriteLocker::scopeTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 
@@ -156,7 +156,7 @@ void tst_QWriteLocker::unlockAndRelockTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 void tst_QWriteLocker::lockerStateTest()
@@ -196,7 +196,7 @@ void tst_QWriteLocker::lockerStateTest()
     QVERIFY(thread->wait());
 
     delete thread;
-    thread = 0;
+    thread = nullptr;
 }
 
 QTEST_MAIN(tst_QWriteLocker)