diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp
index 2d2d351f090..9e6868cf02f 100644
--- a/src/corelib/text/qstring.cpp
+++ b/src/corelib/text/qstring.cpp
@@ -5737,6 +5737,8 @@ QString QString::simplified_helper(const QString &str)
 
 QString QString::simplified_helper(QString &str)
 {
+    if (IS_RAW_DATA(str.d)) // Force a copy, even if not shared:
+        return QStringAlgorithms<const QString>::simplified_helper(str);
     return QStringAlgorithms<QString>::simplified_helper(str);
 }
 
diff --git a/tests/auto/corelib/text/qlocale/tst_qlocale.cpp b/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
index 6bd9e5c25a5..2816ba3bd3d 100644
--- a/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
+++ b/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
@@ -2547,6 +2547,7 @@ void tst_QLocale::monthName()
     QCOMPARE(c.monthName(1, QLocale::LongFormat), QLatin1String("January"));
     QCOMPARE(c.monthName(1, QLocale::ShortFormat), QLatin1String("Jan"));
     QCOMPARE(c.monthName(1, QLocale::NarrowFormat), QLatin1String("1"));
+    QCOMPARE(c.monthName(3).simplified(), "March"); // QTBUG-113415 (crash)
 
     const QLocale de("de_DE");
     QCOMPARE(de.monthName(12, QLocale::LongFormat), QLatin1String("Dezember"));