diff --git a/src/gui/util/qvalidator.cpp b/src/gui/util/qvalidator.cpp
index 95d8b2a542..6f93738340 100644
--- a/src/gui/util/qvalidator.cpp
+++ b/src/gui/util/qvalidator.cpp
@@ -683,8 +683,7 @@ QValidator::State QDoubleValidatorPrivate::validateWithLocale(QString &input, QL
 
     bool ok = false;
     double i = locale.toDouble(input, &ok); // returns 0.0 if !ok
-    if (i == qt_qnan())
-        return QValidator::Invalid;
+    Q_ASSERT(!qIsNaN(i)); // Would be caught by validateChars()
     if (!ok)
         return QValidator::Intermediate;
 
diff --git a/tests/auto/gui/util/qdoublevalidator/tst_qdoublevalidator.cpp b/tests/auto/gui/util/qdoublevalidator/tst_qdoublevalidator.cpp
index fb8e5f0a3a..d1684e9153 100644
--- a/tests/auto/gui/util/qdoublevalidator/tst_qdoublevalidator.cpp
+++ b/tests/auto/gui/util/qdoublevalidator/tst_qdoublevalidator.cpp
@@ -216,6 +216,14 @@ void tst_QDoubleValidator::validate_data()
     QTest::newRow("data_de48") << "de" << 0.0 << 2.0 << 2 << QString("9,9999") << INV << INV;
     QTest::newRow("data_de49") << "de" << 100.0 << 200.0 << 4 << QString("9999,9999") << ITM << INV;
 
+    // using default QDoubleValidator parameters for initialization
+    QTest::newRow("inf") << "C" << -HUGE_VAL << HUGE_VAL << 1000 << QString("inf") << INV << INV;
+    QTest::newRow("+inf") << "C" << -HUGE_VAL << HUGE_VAL << 1000 << QString("+inf") << INV << INV;
+    QTest::newRow("-inf") << "C" << -HUGE_VAL << HUGE_VAL << 1000 << QString("-inf") << INV << INV;
+    QTest::newRow("nan") << "C" << -HUGE_VAL << HUGE_VAL << 1000 << QString("nan") << INV << INV;
+    QTest::newRow("+nan") << "C" << -HUGE_VAL << HUGE_VAL << 1000 << QString("+nan") << INV << INV;
+    QTest::newRow("-nan") << "C" << -HUGE_VAL << HUGE_VAL << 1000 << QString("-nan") << INV << INV;
+
     QString arabicNum;
     arabicNum += QChar(1633); // "18.4" in arabic
     arabicNum += QChar(1640);