diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp
index 85ee6710a08..da212ac2919 100644
--- a/src/corelib/text/qstring.cpp
+++ b/src/corelib/text/qstring.cpp
@@ -5432,7 +5432,7 @@ QString QString::fromUcs4(const char32_t *unicode, qsizetype size)
     Resizes the string to \a size characters and copies \a unicode
     into the string.
 
-    If \a unicode is 0, nothing is copied, but the string is still
+    If \a unicode is \nullptr, nothing is copied, but the string is still
     resized to \a size.
 
     \sa unicode(), setUtf16()
@@ -5451,7 +5451,7 @@ QString& QString::setUnicode(const QChar *unicode, qsizetype size)
     Resizes the string to \a size characters and copies \a unicode
     into the string.
 
-    If \a unicode is 0, nothing is copied, but the string is still
+    If \a unicode is \nullptr, nothing is copied, but the string is still
     resized to \a size.
 
     Note that unlike fromUtf16(), this function does not consider BOMs and
diff --git a/src/corelib/text/qstring.h b/src/corelib/text/qstring.h
index 86f6d829d43..8926f6f3af3 100644
--- a/src/corelib/text/qstring.h
+++ b/src/corelib/text/qstring.h
@@ -1448,8 +1448,8 @@ inline QString QString::fromStdU32String(const std::u32string &s)
 inline std::u32string QString::toStdU32String() const
 {
     std::u32string u32str(length(), char32_t(0));
-    int len = toUcs4_helper(reinterpret_cast<const ushort *>(constData()), length(),
-                            reinterpret_cast<uint*>(&u32str[0]));
+    qsizetype len = toUcs4_helper(reinterpret_cast<const ushort *>(constData()),
+                                  length(), reinterpret_cast<uint*>(&u32str[0]));
     u32str.resize(len);
     return u32str;
 }
diff --git a/src/network/kernel/qauthenticator.cpp b/src/network/kernel/qauthenticator.cpp
index c433b700ea3..a8777962eea 100644
--- a/src/network/kernel/qauthenticator.cpp
+++ b/src/network/kernel/qauthenticator.cpp
@@ -1442,7 +1442,7 @@ static bool qNtlmDecodePhase2(const QByteArray& data, QNtlmPhase2Block& ch)
     ds >> ch.targetInfo;
 
     if (ch.targetName.len > 0) {
-        if (ch.targetName.len + ch.targetName.offset > (unsigned)data.size())
+        if (qsizetype(ch.targetName.len + ch.targetName.offset) > data.size())
             return false;
 
         ch.targetNameStr = qStringFromUcs2Le(data.mid(ch.targetName.offset, ch.targetName.len));