diff --git a/src/corelib/serialization/qxmlstream.cpp b/src/corelib/serialization/qxmlstream.cpp
index 3323ff0707..5e3e07f6ee 100644
--- a/src/corelib/serialization/qxmlstream.cpp
+++ b/src/corelib/serialization/qxmlstream.cpp
@@ -1020,7 +1020,7 @@ bool QXmlStreamReaderPrivate::scanString(const char *str, short tokenToInject, b
     }
     textBuffer += QLatin1StringView(str, n);
     if (requireSpace) {
-        int s = fastScanSpace();
+        const qsizetype s = fastScanSpace();
         if (!s || atEnd) {
             qsizetype pos = textBuffer.size() - n - s;
             putString(textBuffer, pos);
@@ -1132,9 +1132,9 @@ bool QXmlStreamReaderPrivate::scanAttType()
  encountered.
 
  */
-inline int QXmlStreamReaderPrivate::fastScanLiteralContent()
+inline qsizetype QXmlStreamReaderPrivate::fastScanLiteralContent()
 {
-    int n = 0;
+    qsizetype n = 0;
     uint c;
     while ((c = getChar()) != StreamEOF) {
         switch (ushort(c)) {
@@ -1182,9 +1182,9 @@ inline int QXmlStreamReaderPrivate::fastScanLiteralContent()
     return n;
 }
 
-inline int QXmlStreamReaderPrivate::fastScanSpace()
+inline qsizetype QXmlStreamReaderPrivate::fastScanSpace()
 {
-    int n = 0;
+    qsizetype n = 0;
     uint c;
     while ((c = getChar()) != StreamEOF) {
         switch (c) {
@@ -1215,9 +1215,9 @@ inline int QXmlStreamReaderPrivate::fastScanSpace()
   Used for text nodes essentially. That is, characters appearing
   inside elements.
  */
-inline int QXmlStreamReaderPrivate::fastScanContentCharList()
+inline qsizetype QXmlStreamReaderPrivate::fastScanContentCharList()
 {
-    int n = 0;
+    qsizetype n = 0;
     uint c;
     while ((c = getChar()) != StreamEOF) {
         switch (ushort(c)) {
@@ -1279,9 +1279,9 @@ inline int QXmlStreamReaderPrivate::fastScanContentCharList()
     return n;
 }
 
-inline int QXmlStreamReaderPrivate::fastScanName(qint16 *prefix)
+inline qsizetype QXmlStreamReaderPrivate::fastScanName(qint16 *prefix)
 {
-    int n = 0;
+    qsizetype n = 0;
     uint c;
     while ((c = getChar()) != StreamEOF) {
         if (n >= 4096) {
@@ -1400,9 +1400,9 @@ static inline NameChar fastDetermineNameChar(QChar ch)
     return NotName;
 }
 
-inline int QXmlStreamReaderPrivate::fastScanNMTOKEN()
+inline qsizetype QXmlStreamReaderPrivate::fastScanNMTOKEN()
 {
-    int n = 0;
+    qsizetype n = 0;
     uint c;
     while ((c = getChar()) != StreamEOF) {
         if (fastDetermineNameChar(QChar(c)) == NotName) {
diff --git a/src/corelib/serialization/qxmlstream.g b/src/corelib/serialization/qxmlstream.g
index db9be6d8ac..201e06ba20 100644
--- a/src/corelib/serialization/qxmlstream.g
+++ b/src/corelib/serialization/qxmlstream.g
@@ -1217,9 +1217,9 @@ attribute ::= qname space_opt EQ space_opt attribute_value;
                 if (normalize) {
                     // normalize attribute value (simplify and trim)
                     const qsizetype pos = textBuffer.size();
-                    int n = 0;
+                    qsizetype n = 0;
                     bool wasSpace = true;
-                    for (int i = 0; i < attribute.value.len; ++i) {
+                    for (qsizetype i = 0; i < attribute.value.len; ++i) {
                         QChar c = textBuffer.at(attribute.value.pos + i);
                         if (c.unicode() == ' ') {
                             if (wasSpace)
diff --git a/src/corelib/serialization/qxmlstream_p.h b/src/corelib/serialization/qxmlstream_p.h
index 4897735796..56a40885bb 100644
--- a/src/corelib/serialization/qxmlstream_p.h
+++ b/src/corelib/serialization/qxmlstream_p.h
@@ -410,7 +410,7 @@ public:
     int stack_size;
     struct Value {
         qsizetype pos;  // offset into textBuffer
-        int len;
+        qsizetype len;  // length incl. prefix (if any)
         qint16 prefix;  // prefix of a name (as in "prefix:name") limited to 4k in fastScanName()
         ushort c;
     };
@@ -504,11 +504,11 @@ public:
 
     // scan optimization functions. Not strictly necessary but LALR is
     // not very well suited for scanning fast
-    int fastScanLiteralContent();
-    int fastScanSpace();
-    int fastScanContentCharList();
-    int fastScanName(qint16 *prefix = nullptr);
-    inline int fastScanNMTOKEN();
+    qsizetype fastScanLiteralContent();
+    qsizetype fastScanSpace();
+    qsizetype fastScanContentCharList();
+    qsizetype fastScanName(qint16 *prefix = nullptr);
+    inline qsizetype fastScanNMTOKEN();
 
 
     bool parse();
diff --git a/src/corelib/serialization/qxmlstreamparser_p.h b/src/corelib/serialization/qxmlstreamparser_p.h
index de8cfcbd23..b72ab34bea 100644
--- a/src/corelib/serialization/qxmlstreamparser_p.h
+++ b/src/corelib/serialization/qxmlstreamparser_p.h
@@ -780,9 +780,9 @@ bool QXmlStreamReaderPrivate::parse()
                 if (normalize) {
                     // normalize attribute value (simplify and trim)
                     const qsizetype pos = textBuffer.size();
-                    int n = 0;
+                    qsizetype n = 0;
                     bool wasSpace = true;
-                    for (int i = 0; i < attribute.value.len; ++i) {
+                    for (qsizetype i = 0; i < attribute.value.len; ++i) {
                         QChar c = textBuffer.at(attribute.value.pos + i);
                         if (c.unicode() == ' ') {
                             if (wasSpace)