1 files changed, 5 insertions, 7 deletions
diff --git a/src/corelib/time/qgregoriancalendar.cpp b/src/corelib/time/qgregoriancalendar.cpp
index 633b1ea94e..f562413dd1 100644
--- a/src/corelib/time/qgregoriancalendar.cpp
+++ b/src/corelib/time/qgregoriancalendar.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2019 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -63,7 +63,10 @@ using namespace QRoundingDown;
 QGregorianCalendar::QGregorianCalendar()
     : QRomanCalendar(QStringLiteral("Gregorian"), QCalendar::System::Gregorian)
 {
-    registerAlias(QStringLiteral("gregory"));
+    if (~calendarId()) {
+        Q_ASSERT(calendarSystem() == QCalendar::System::Gregorian);
+        registerAlias(QStringLiteral("gregory"));
+    } // else: being ignored in favor of a duplicate created at the same time
 }
 
 QString QGregorianCalendar::name() const
@@ -71,11 +74,6 @@ QString QGregorianCalendar::name() const
     return QStringLiteral("Gregorian");
 }
 
-QCalendar::System QGregorianCalendar::calendarSystem() const
-{
-    return QCalendar::System::Gregorian;
-}
-
 bool QGregorianCalendar::isLeapYear(int year) const
 {
     return leapTest(year);