diff --git a/src/corelib/tools/qcollator_icu.cpp b/src/corelib/tools/qcollator_icu.cpp
index 43bbe0ea79..fd621983d3 100644
--- a/src/corelib/tools/qcollator_icu.cpp
+++ b/src/corelib/tools/qcollator_icu.cpp
@@ -61,7 +61,7 @@ void QCollatorPrivate::init()
     collator = ucol_open(name.constData(), &status);
     if (U_FAILURE(status)) {
         qWarning("Could not create collator: %d", status);
-        collator = 0;
+        collator = nullptr;
         dirty = false;
         return;
     }
@@ -100,7 +100,7 @@ void QCollatorPrivate::cleanup()
 {
     if (collator)
         ucol_close(collator);
-    collator = 0;
+    collator = nullptr;
 }
 
 int QCollator::compare(const QChar *s1, int len1, const QChar *s2, int len2) const
diff --git a/src/corelib/tools/qcollator_p.h b/src/corelib/tools/qcollator_p.h
index 18a43f0de6..f244a7721a 100644
--- a/src/corelib/tools/qcollator_p.h
+++ b/src/corelib/tools/qcollator_p.h
@@ -68,21 +68,25 @@ QT_BEGIN_NAMESPACE
 #if QT_CONFIG(icu)
 typedef UCollator *CollatorType;
 typedef QByteArray CollatorKeyType;
+const CollatorType NoCollator = nullptr;
 
 #elif defined(Q_OS_OSX)
 typedef CollatorRef CollatorType;
 typedef QVector<UCCollationValue> CollatorKeyType;
+const CollatorType NoCollator = 0;
 
 #elif defined(Q_OS_WIN)
 typedef QString CollatorKeyType;
 typedef int CollatorType;
+const CollatorType NoCollator = 0;
 #  ifdef Q_OS_WINRT
 #    define USE_COMPARESTRINGEX
 #  endif
 
-#else //posix
+#else // posix - ignores CollatorType collator, only handles system locale
 typedef QVector<wchar_t> CollatorKeyType;
 typedef int CollatorType;
+const CollatorType NoCollator = 0;
 #endif
 
 class QCollatorPrivate
@@ -102,14 +106,14 @@ public:
     bool ignorePunctuation = false;
     bool dirty = true;
 
-    CollatorType collator = 0;
+    CollatorType collator = NoCollator;
 
     QCollatorPrivate(const QLocale &locale) : locale(locale) {}
     ~QCollatorPrivate() { cleanup(); }
 
     void clear() {
         cleanup();
-        collator = 0;
+        collator = NoCollator;
     }
 
     // Implemented by each back-end, in its own way: