diff --git a/src/corelib/text/qstringiterator_p.h b/src/corelib/text/qstringiterator_p.h
index 8d13778186c..bb1a8616378 100644
--- a/src/corelib/text/qstringiterator_p.h
+++ b/src/corelib/text/qstringiterator_p.h
@@ -25,6 +25,8 @@ class QStringIterator
 {
     QString::const_iterator i, pos, e;
     static_assert((std::is_same<QString::const_iterator, const QChar *>::value));
+    static bool less(const QChar *lhs, const QChar *rhs) noexcept
+    { return std::less{}(lhs, rhs); }
 public:
     explicit QStringIterator(QStringView string, qsizetype idx = 0)
         : i(string.begin()),
@@ -59,7 +61,8 @@ public:
 
     inline void setPosition(QString::const_iterator position)
     {
-        Q_ASSERT_X(i <= position && position <= e, Q_FUNC_INFO, "position out of bounds");
+        Q_ASSERT_X(!less(position, i) && !less(e, position),
+                   Q_FUNC_INFO, "position out of bounds");
         pos = position;
     }
 
@@ -67,7 +70,7 @@ public:
 
     inline bool hasNext() const
     {
-        return pos < e;
+        return less(pos, e);
     }
 
     inline void advance()
@@ -95,7 +98,7 @@ public:
         Q_ASSERT_X(hasNext(), Q_FUNC_INFO, "iterator hasn't a next item");
 
         if (Q_UNLIKELY(pos->isHighSurrogate())) {
-            Q_ASSERT(pos + 1 < e && pos[1].isLowSurrogate());
+            Q_ASSERT(less(pos + 1, e) && pos[1].isLowSurrogate());
             return QChar::surrogateToUcs4(pos[0], pos[1]);
         }
 
@@ -148,7 +151,7 @@ public:
 
     inline bool hasPrevious() const
     {
-        return pos > i;
+        return less(i, pos);
     }
 
     inline void recede()
@@ -177,7 +180,7 @@ public:
         Q_ASSERT_X(hasPrevious(), Q_FUNC_INFO, "iterator hasn't a previous item");
 
         if (Q_UNLIKELY(pos[-1].isLowSurrogate())) {
-            Q_ASSERT(pos > i + 1 && pos[-2].isHighSurrogate());
+            Q_ASSERT(less(i + 1, pos) && pos[-2].isHighSurrogate());
             return QChar::surrogateToUcs4(pos[-2], pos[-1]);
         }
         return pos[-1].unicode();