diff --git a/src/corelib/kernel/qvariant.cpp b/src/corelib/kernel/qvariant.cpp
index 3fe2be2a7c..f339ff66cd 100644
--- a/src/corelib/kernel/qvariant.cpp
+++ b/src/corelib/kernel/qvariant.cpp
@@ -1876,13 +1876,13 @@ QVariant::QVariant(const char *val)
 */
 
 /*!
-  \fn QVariant::QVariant(const QDate &val)
+  \fn QVariant::QVariant(QDate val)
 
     Constructs a new variant with a date value, \a val.
 */
 
 /*!
-  \fn QVariant::QVariant(const QTime &val)
+  \fn QVariant::QVariant(QTime val)
 
     Constructs a new variant with a time value, \a val.
 */
@@ -2160,10 +2160,10 @@ QVariant::QVariant(const QStringList &val)
     : d(StringList)
 { v_construct<QStringList>(&d, val); }
 
-QVariant::QVariant(const QDate &val)
+QVariant::QVariant(QDate val)
     : d(Date)
 { v_construct<QDate>(&d, val); }
-QVariant::QVariant(const QTime &val)
+QVariant::QVariant(QTime val)
     : d(Time)
 { v_construct<QTime>(&d, val); }
 QVariant::QVariant(const QDateTime &val)
diff --git a/src/corelib/kernel/qvariant.h b/src/corelib/kernel/qvariant.h
index b09c706df2..5f0fdd4bf5 100644
--- a/src/corelib/kernel/qvariant.h
+++ b/src/corelib/kernel/qvariant.h
@@ -235,8 +235,8 @@ class Q_CORE_EXPORT QVariant
     QVariant(QLatin1String string);
     QVariant(const QStringList &stringlist);
     QVariant(QChar qchar);
-    QVariant(const QDate &date);
-    QVariant(const QTime &time);
+    QVariant(QDate date);
+    QVariant(QTime time);
     QVariant(const QDateTime &datetime);
     QVariant(const QList<QVariant> &list);
     QVariant(const QMap<QString,QVariant> &map);
diff --git a/src/corelib/text/qlocale.cpp b/src/corelib/text/qlocale.cpp
index a1c8574f91..9e3043046d 100644
--- a/src/corelib/text/qlocale.cpp
+++ b/src/corelib/text/qlocale.cpp
@@ -2054,7 +2054,7 @@ QString QLocale::toString(qulonglong i) const
     \sa QDate::toString()
 */
 
-QString QLocale::toString(const QDate &date, const QString &format) const
+QString QLocale::toString(QDate date, const QString &format) const
 {
     return QCalendar().dateTimeToString(format, QDateTime(), date, QTime(), *this);
 }
@@ -2069,7 +2069,7 @@ QString QLocale::toString(const QDate &date, const QString &format) const
 
     \sa QDate::toString()
 */
-QString QLocale::toString(const QDate &date, QStringView format) const
+QString QLocale::toString(QDate date, QStringView format) const
 {
     return QCalendar().dateTimeToString(format, QDateTime(), date, QTime(), *this);
 }
@@ -2082,7 +2082,7 @@ QString QLocale::toString(const QDate &date, QStringView format) const
     represent.
 */
 
-QString QLocale::toString(const QDate &date, FormatType format) const
+QString QLocale::toString(QDate date, FormatType format) const
 {
     if (!date.isValid())
         return QString();
@@ -2127,7 +2127,7 @@ static bool timeFormatContainsAP(QStringView format)
 
     \sa QTime::toString()
 */
-QString QLocale::toString(const QTime &time, const QString &format) const
+QString QLocale::toString(QTime time, const QString &format) const
 {
     return QCalendar().dateTimeToString(format, QDateTime(), QDate(), time, *this);
 }
@@ -2142,7 +2142,7 @@ QString QLocale::toString(const QTime &time, const QString &format) const
 
     \sa QTime::toString()
 */
-QString QLocale::toString(const QTime &time, QStringView format) const
+QString QLocale::toString(QTime time, QStringView format) const
 {
     return QCalendar().dateTimeToString(format, QDateTime(), QDate(), time, *this);
 }
@@ -2178,12 +2178,12 @@ QString QLocale::toString(const QDateTime &dateTime, QStringView format) const
     return QCalendar().dateTimeToString(format, dateTime, QDate(), QTime(), *this);
 }
 
-QString QLocale::toString(const QDate &date, QStringView format, QCalendar cal) const
+QString QLocale::toString(QDate date, QStringView format, QCalendar cal) const
 {
     return cal.dateTimeToString(format, QDateTime(), date, QTime(), *this);
 }
 
-QString QLocale::toString(const QDate &date, QLocale::FormatType format, QCalendar cal) const
+QString QLocale::toString(QDate date, QLocale::FormatType format, QCalendar cal) const
 {
     if (!date.isValid())
         return QString();
@@ -2265,7 +2265,7 @@ QString QLocale::toString(const QDateTime &dateTime, FormatType format) const
     specified \a format.
 */
 
-QString QLocale::toString(const QTime &time, FormatType format) const
+QString QLocale::toString(QTime time, FormatType format) const
 {
     if (!time.isValid())
         return QString();
@@ -3299,7 +3299,7 @@ QString QLocale::pmText() const
 // Another intrusion from QCalendar, using some of the tools above:
 
 QString QCalendarBackend::dateTimeToString(QStringView format, const QDateTime &datetime,
-                                           const QDate &dateOnly, const QTime &timeOnly,
+                                           QDate dateOnly, QTime timeOnly,
                                            const QLocale &locale) const
 {
     QDate date;
diff --git a/src/corelib/text/qlocale.h b/src/corelib/text/qlocale.h
index a4262a3ab8..3f1a8f2679 100644
--- a/src/corelib/text/qlocale.h
+++ b/src/corelib/text/qlocale.h
@@ -1007,22 +1007,22 @@ public:
     inline QString toString(float i, char f = 'g', int prec = 6) const;
 
 #if QT_STRINGVIEW_LEVEL < 2
-    QString toString(const QDate &date, const QString &formatStr) const;
-    QString toString(const QTime &time, const QString &formatStr) const;
+    QString toString(QDate date, const QString &formatStr) const;
+    QString toString(QTime time, const QString &formatStr) const;
     QString toString(const QDateTime &dateTime, const QString &format) const;
 #endif
-    QString toString(const QDate &date, QStringView formatStr) const;
-    QString toString(const QTime &time, QStringView formatStr) const;
+    QString toString(QDate date, QStringView formatStr) const;
+    QString toString(QTime time, QStringView formatStr) const;
     QString toString(const QDateTime &dateTime, QStringView format) const;
-    QString toString(const QDate &date, FormatType format = LongFormat) const;
-    QString toString(const QTime &time, FormatType format = LongFormat) const;
+    QString toString(QDate date, FormatType format = LongFormat) const;
+    QString toString(QTime time, FormatType format = LongFormat) const;
     QString toString(const QDateTime &dateTime, FormatType format = LongFormat) const;
     /* Removing default value for `format' is done intentionally,
      * after all tests we will remove non-calendar-aware version of these functions,
      * and add a default value for both calendar instance, and format
      */
-    QString toString(const QDate &date, QStringView formatStr, QCalendar cal) const;
-    QString toString(const QDate &date, FormatType format, QCalendar cal) const;
+    QString toString(QDate date, QStringView formatStr, QCalendar cal) const;
+    QString toString(QDate date, FormatType format, QCalendar cal) const;
     QString toString(const QDateTime &dateTime, FormatType format, QCalendar cal) const;
     QString toString(const QDateTime &dateTime, QStringView formatStr, QCalendar cal) const;
 
diff --git a/src/corelib/time/qcalendar.cpp b/src/corelib/time/qcalendar.cpp
index 32f0a511a3..02788f5e23 100644
--- a/src/corelib/time/qcalendar.cpp
+++ b/src/corelib/time/qcalendar.cpp
@@ -518,7 +518,7 @@ int QCalendarBackend::dayOfWeek(qint64 jd) const
 
 /*!
     \fn QString QCalendarBackend::dateTimeToString(QStringView format, const QDateTime &datetime,
-                                                   const QDate &dateOnly, const QTime &timeOnly,
+                                                   QDate dateOnly, QTime timeOnly,
                                                    const QLocale &locale) const
 
     Returns a string representing a given date, time or date-time.
@@ -1095,7 +1095,7 @@ QString QCalendar::standaloneWeekDayName(const QLocale &locale, int day,
     \sa monthName(), weekDayName(), QDate::toString(), QTime::toString()
 */
 QString QCalendar::dateTimeToString(QStringView format, const QDateTime &datetime,
-                                    const QDate &dateOnly, const QTime &timeOnly,
+                                    QDate dateOnly, QTime timeOnly,
                                     const QLocale &locale) const
 {
     return d ? d->dateTimeToString(format, datetime, dateOnly, timeOnly, locale) : QString();
diff --git a/src/corelib/time/qcalendar.h b/src/corelib/time/qcalendar.h
index 42c8e150c5..5eb2e541c8 100644
--- a/src/corelib/time/qcalendar.h
+++ b/src/corelib/time/qcalendar.h
@@ -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.
@@ -178,7 +178,7 @@ public:
 
     // Formatting of date-times:
     QString dateTimeToString(QStringView format, const QDateTime &datetime,
-                             const QDate &dateOnly, const QTime &timeOnly,
+                             QDate dateOnly, QTime timeOnly,
                              const QLocale &locale) const;
 
     // What's available ?
diff --git a/src/corelib/time/qcalendarbackend_p.h b/src/corelib/time/qcalendarbackend_p.h
index ea837a4804..129e86494b 100644
--- a/src/corelib/time/qcalendarbackend_p.h
+++ b/src/corelib/time/qcalendarbackend_p.h
@@ -126,7 +126,7 @@ public:
 
     // Formatting of date-times (implemented in qlocale.cpp):
     virtual QString dateTimeToString(QStringView format, const QDateTime &datetime,
-                                     const QDate &dateOnly, const QTime &timeOnly,
+                                     QDate dateOnly, QTime timeOnly,
                                      const QLocale &locale) const;
 
     // Calendar enumeration by name:
diff --git a/src/corelib/time/qdatetime.cpp b/src/corelib/time/qdatetime.cpp
index 86c08058fc..e116e539b9 100644
--- a/src/corelib/time/qdatetime.cpp
+++ b/src/corelib/time/qdatetime.cpp
@@ -1561,7 +1561,7 @@ QDate QDate::addYears(int nyears) const
     \sa addDays()
 */
 
-qint64 QDate::daysTo(const QDate &d) const
+qint64 QDate::daysTo(QDate d) const
 {
     if (isNull() || d.isNull())
         return 0;
@@ -1572,7 +1572,7 @@ qint64 QDate::daysTo(const QDate &d) const
 
 
 /*!
-    \fn bool QDate::operator==(const QDate &d) const
+    \fn bool QDate::operator==(QDate d) const
 
     Returns \c true if this date is equal to \a d; otherwise returns
     false.
@@ -1580,35 +1580,35 @@ qint64 QDate::daysTo(const QDate &d) const
 */
 
 /*!
-    \fn bool QDate::operator!=(const QDate &d) const
+    \fn bool QDate::operator!=(QDate d) const
 
     Returns \c true if this date is different from \a d; otherwise
     returns \c false.
 */
 
 /*!
-    \fn bool QDate::operator<(const QDate &d) const
+    \fn bool QDate::operator<(QDate d) const
 
     Returns \c true if this date is earlier than \a d; otherwise returns
     false.
 */
 
 /*!
-    \fn bool QDate::operator<=(const QDate &d) const
+    \fn bool QDate::operator<=(QDate d) const
 
     Returns \c true if this date is earlier than or equal to \a d;
     otherwise returns \c false.
 */
 
 /*!
-    \fn bool QDate::operator>(const QDate &d) const
+    \fn bool QDate::operator>(QDate d) const
 
     Returns \c true if this date is later than \a d; otherwise returns
     false.
 */
 
 /*!
-    \fn bool QDate::operator>=(const QDate &d) const
+    \fn bool QDate::operator>=(QDate d) const
 
     Returns \c true if this date is later than or equal to \a d;
     otherwise returns \c false.
@@ -2219,7 +2219,7 @@ QTime QTime::addSecs(int s) const
     \sa addSecs(), QDateTime::secsTo()
 */
 
-int QTime::secsTo(const QTime &t) const
+int QTime::secsTo(QTime t) const
 {
     if (!isValid() || !t.isValid())
         return 0;
@@ -2271,7 +2271,7 @@ QTime QTime::addMSecs(int ms) const
     \sa secsTo(), addMSecs(), QDateTime::msecsTo()
 */
 
-int QTime::msecsTo(const QTime &t) const
+int QTime::msecsTo(QTime t) const
 {
     if (!isValid() || !t.isValid())
         return 0;
@@ -2280,38 +2280,38 @@ int QTime::msecsTo(const QTime &t) const
 
 
 /*!
-    \fn bool QTime::operator==(const QTime &t) const
+    \fn bool QTime::operator==(QTime t) const
 
     Returns \c true if this time is equal to \a t; otherwise returns \c false.
 */
 
 /*!
-    \fn bool QTime::operator!=(const QTime &t) const
+    \fn bool QTime::operator!=(QTime t) const
 
     Returns \c true if this time is different from \a t; otherwise returns \c false.
 */
 
 /*!
-    \fn bool QTime::operator<(const QTime &t) const
+    \fn bool QTime::operator<(QTime t) const
 
     Returns \c true if this time is earlier than \a t; otherwise returns \c false.
 */
 
 /*!
-    \fn bool QTime::operator<=(const QTime &t) const
+    \fn bool QTime::operator<=(QTime t) const
 
     Returns \c true if this time is earlier than or equal to \a t;
     otherwise returns \c false.
 */
 
 /*!
-    \fn bool QTime::operator>(const QTime &t) const
+    \fn bool QTime::operator>(QTime t) const
 
     Returns \c true if this time is later than \a t; otherwise returns \c false.
 */
 
 /*!
-    \fn bool QTime::operator>=(const QTime &t) const
+    \fn bool QTime::operator>=(QTime t) const
 
     Returns \c true if this time is later than or equal to \a t;
     otherwise returns \c false.
@@ -3437,7 +3437,7 @@ inline QDateTimePrivate *QDateTime::Data::operator->()
  *****************************************************************************/
 
 Q_NEVER_INLINE
-QDateTime::Data QDateTimePrivate::create(const QDate &toDate, const QTime &toTime, Qt::TimeSpec toSpec,
+QDateTime::Data QDateTimePrivate::create(QDate toDate, QTime toTime, Qt::TimeSpec toSpec,
                                          int offsetSeconds)
 {
     QDateTime::Data result(toSpec);
@@ -3447,7 +3447,7 @@ QDateTime::Data QDateTimePrivate::create(const QDate &toDate, const QTime &toTim
 }
 
 #if QT_CONFIG(timezone)
-inline QDateTime::Data QDateTimePrivate::create(const QDate &toDate, const QTime &toTime,
+inline QDateTime::Data QDateTimePrivate::create(QDate toDate, QTime toTime,
                                                 const QTimeZone &toTimeZone)
 {
     QDateTime::Data result(Qt::TimeZone);
@@ -3652,35 +3652,13 @@ QDateTime::QDateTime() noexcept(Data::CanBeSmall)
 
     \sa QDate::startOfDay()
 */
-QDateTime::QDateTime(const QDate &date)
+QDateTime::QDateTime(QDate date)
     : QDateTime(date.startOfDay(Qt::LocalTime, 0))
 {
 }
 #endif
 
 /*!
-    Constructs a datetime with the given \a date and \a time, using
-    the time specification defined by \a spec.
-
-    If \a date is valid and \a time is not, the time will be set to midnight.
-
-    If \a spec is Qt::OffsetFromUTC then it will be set to Qt::UTC, i.e. an
-    offset of 0 seconds. To create a Qt::OffsetFromUTC datetime use the
-    correct constructor.
-
-    If \a spec is Qt::TimeZone then the spec will be set to Qt::LocalTime,
-    i.e. the current system time zone.  To create a Qt::TimeZone datetime
-    use the correct constructor.
-*/
-
-QDateTime::QDateTime(const QDate &date, const QTime &time, Qt::TimeSpec spec)
-    : d(QDateTimePrivate::create(date, time, spec, 0))
-{
-}
-
-/*!
-    \since 5.2
-
     Constructs a datetime with the given \a date and \a time, using
     the time specification defined by \a spec and \a offsetSeconds seconds.
 
@@ -3696,7 +3674,7 @@ QDateTime::QDateTime(const QDate &date, const QTime &time, Qt::TimeSpec spec)
     use the correct constructor.
 */
 
-QDateTime::QDateTime(const QDate &date, const QTime &time, Qt::TimeSpec spec, int offsetSeconds)
+QDateTime::QDateTime(QDate date, QTime time, Qt::TimeSpec spec, int offsetSeconds)
          : d(QDateTimePrivate::create(date, time, spec, offsetSeconds))
 {
 }
@@ -3713,7 +3691,7 @@ QDateTime::QDateTime(const QDate &date, const QTime &time, Qt::TimeSpec spec, in
     If \a timeZone is invalid then the datetime will be invalid.
 */
 
-QDateTime::QDateTime(const QDate &date, const QTime &time, const QTimeZone &timeZone)
+QDateTime::QDateTime(QDate date, QTime time, const QTimeZone &timeZone)
     : d(QDateTimePrivate::create(date, time, timeZone))
 {
 }
@@ -4001,7 +3979,7 @@ bool QDateTime::isDaylightTime() const
     \sa date(), setTime(), setTimeSpec()
 */
 
-void QDateTime::setDate(const QDate &date)
+void QDateTime::setDate(QDate date)
 {
     setDateTime(d, date, time());
 }
@@ -4019,7 +3997,7 @@ void QDateTime::setDate(const QDate &date)
     \sa time(), setDate(), setTimeSpec()
 */
 
-void QDateTime::setTime(const QTime &time)
+void QDateTime::setTime(QTime time)
 {
     setDateTime(d, date(), time);
 }
@@ -5575,7 +5553,7 @@ QDateTime QDateTime::fromString(const QString &string, const QString &format)
     \sa {Serializing Qt Data Types}
 */
 
-QDataStream &operator<<(QDataStream &out, const QDate &date)
+QDataStream &operator<<(QDataStream &out, QDate date)
 {
     if (out.version() < QDataStream::Qt_5_0)
         return out << quint32(date.jd);
@@ -5615,7 +5593,7 @@ QDataStream &operator>>(QDataStream &in, QDate &date)
     \sa {Serializing Qt Data Types}
 */
 
-QDataStream &operator<<(QDataStream &out, const QTime &time)
+QDataStream &operator<<(QDataStream &out, QTime time)
 {
     if (out.version() >= QDataStream::Qt_4_0) {
         return out << quint32(time.mds);
@@ -5795,7 +5773,7 @@ QDataStream &operator>>(QDataStream &in, QDateTime &dateTime)
 *****************************************************************************/
 
 #if !defined(QT_NO_DEBUG_STREAM) && QT_CONFIG(datestring)
-QDebug operator<<(QDebug dbg, const QDate &date)
+QDebug operator<<(QDebug dbg, QDate date)
 {
     QDebugStateSaver saver(dbg);
     dbg.nospace() << "QDate(";
@@ -5807,7 +5785,7 @@ QDebug operator<<(QDebug dbg, const QDate &date)
     return dbg;
 }
 
-QDebug operator<<(QDebug dbg, const QTime &time)
+QDebug operator<<(QDebug dbg, QTime time)
 {
     QDebugStateSaver saver(dbg);
     dbg.nospace() << "QTime(";
@@ -5863,24 +5841,24 @@ uint qHash(const QDateTime &key, uint seed)
     return key.isValid() ? qHash(key.toMSecsSinceEpoch(), seed) : seed;
 }
 
-/*! \fn uint qHash(const QDate &key, uint seed = 0)
+/*! \fn uint qHash(QDate key, uint seed = 0)
     \relates QHash
     \since 5.0
 
     Returns the hash value for the \a key, using \a seed to seed the calculation.
 */
-uint qHash(const QDate &key, uint seed) noexcept
+uint qHash(QDate key, uint seed) noexcept
 {
     return qHash(key.toJulianDay(), seed);
 }
 
-/*! \fn uint qHash(const QTime &key, uint seed = 0)
+/*! \fn uint qHash(QTime key, uint seed = 0)
     \relates QHash
     \since 5.0
 
     Returns the hash value for the \a key, using \a seed to seed the calculation.
 */
-uint qHash(const QTime &key, uint seed) noexcept
+uint qHash(QTime key, uint seed) noexcept
 {
     return qHash(key.msecsSinceStartOfDay(), seed);
 }
diff --git a/src/corelib/time/qdatetime.h b/src/corelib/time/qdatetime.h
index 645923ada8..b1a3e0b1d6 100644
--- a/src/corelib/time/qdatetime.h
+++ b/src/corelib/time/qdatetime.h
@@ -143,14 +143,14 @@ public:
     Q_REQUIRED_RESULT QDate addYears(int years) const;
     Q_REQUIRED_RESULT QDate addMonths(int months, QCalendar cal) const;
     Q_REQUIRED_RESULT QDate addYears(int years, QCalendar cal) const;
-    qint64 daysTo(const QDate &) const; // ### Qt 6: QDate
+    qint64 daysTo(QDate d) const;
 
-    Q_DECL_CONSTEXPR bool operator==(const QDate &other) const { return jd == other.jd; }
-    Q_DECL_CONSTEXPR bool operator!=(const QDate &other) const { return jd != other.jd; }
-    Q_DECL_CONSTEXPR bool operator< (const QDate &other) const { return jd <  other.jd; }
-    Q_DECL_CONSTEXPR bool operator<=(const QDate &other) const { return jd <= other.jd; }
-    Q_DECL_CONSTEXPR bool operator> (const QDate &other) const { return jd >  other.jd; }
-    Q_DECL_CONSTEXPR bool operator>=(const QDate &other) const { return jd >= other.jd; }
+    Q_DECL_CONSTEXPR bool operator==(QDate other) const { return jd == other.jd; }
+    Q_DECL_CONSTEXPR bool operator!=(QDate other) const { return jd != other.jd; }
+    Q_DECL_CONSTEXPR bool operator< (QDate other) const { return jd <  other.jd; }
+    Q_DECL_CONSTEXPR bool operator<=(QDate other) const { return jd <= other.jd; }
+    Q_DECL_CONSTEXPR bool operator> (QDate other) const { return jd >  other.jd; }
+    Q_DECL_CONSTEXPR bool operator>=(QDate other) const { return jd >= other.jd; }
 
     static QDate currentDate();
 #if QT_CONFIG(datestring)
@@ -176,7 +176,7 @@ private:
     friend class QDateTime;
     friend class QDateTimePrivate;
 #ifndef QT_NO_DATASTREAM
-    friend Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, const QDate &);
+    friend Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, QDate);
     friend Q_CORE_EXPORT QDataStream &operator>>(QDataStream &, QDate &);
 #endif
 };
@@ -208,16 +208,16 @@ public:
     bool setHMS(int h, int m, int s, int ms = 0);
 
     Q_REQUIRED_RESULT QTime addSecs(int secs) const;
-    int secsTo(const QTime &) const; // ### Qt 6: plain QTime
+    int secsTo(QTime t) const;
     Q_REQUIRED_RESULT QTime addMSecs(int ms) const;
-    int msecsTo(const QTime &) const; // ### Qt 6: plain QTime
+    int msecsTo(QTime t) const;
 
-    Q_DECL_CONSTEXPR bool operator==(const QTime &other) const { return mds == other.mds; }
-    Q_DECL_CONSTEXPR bool operator!=(const QTime &other) const { return mds != other.mds; }
-    Q_DECL_CONSTEXPR bool operator< (const QTime &other) const { return mds <  other.mds; }
-    Q_DECL_CONSTEXPR bool operator<=(const QTime &other) const { return mds <= other.mds; }
-    Q_DECL_CONSTEXPR bool operator> (const QTime &other) const { return mds >  other.mds; }
-    Q_DECL_CONSTEXPR bool operator>=(const QTime &other) const { return mds >= other.mds; }
+    Q_DECL_CONSTEXPR bool operator==(QTime other) const { return mds == other.mds; }
+    Q_DECL_CONSTEXPR bool operator!=(QTime other) const { return mds != other.mds; }
+    Q_DECL_CONSTEXPR bool operator< (QTime other) const { return mds <  other.mds; }
+    Q_DECL_CONSTEXPR bool operator<=(QTime other) const { return mds <= other.mds; }
+    Q_DECL_CONSTEXPR bool operator> (QTime other) const { return mds >  other.mds; }
+    Q_DECL_CONSTEXPR bool operator>=(QTime other) const { return mds >= other.mds; }
 
     static Q_DECL_CONSTEXPR inline QTime fromMSecsSinceStartOfDay(int msecs) { return QTime(msecs); }
     Q_DECL_CONSTEXPR inline int msecsSinceStartOfDay() const { return mds == NullTime ? 0 : mds; }
@@ -241,8 +241,8 @@ private:
 
     friend class QDateTime;
     friend class QDateTimePrivate;
-#ifndef QT_NO_DATASTREAM // ### Qt 6: plain QTime
-    friend Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, const QTime &);
+#ifndef QT_NO_DATASTREAM
+    friend Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, QTime);
     friend Q_CORE_EXPORT QDataStream &operator>>(QDataStream &, QTime &);
 #endif
 };
@@ -293,13 +293,11 @@ class Q_CORE_EXPORT QDateTime
 public:
     QDateTime() noexcept(Data::CanBeSmall);
 #if QT_DEPRECATED_SINCE(5, 15) // ### Qt 6: remove
-    QT_DEPRECATED_X("Use QDate::startOfDay()") explicit QDateTime(const QDate &);
+    QT_DEPRECATED_X("Use QDate::startOfDay()") explicit QDateTime(QDate);
 #endif
-    QDateTime(const QDate &, const QTime &, Qt::TimeSpec spec = Qt::LocalTime);
-    // ### Qt 6: Merge with above with default offsetSeconds = 0
-    QDateTime(const QDate &date, const QTime &time, Qt::TimeSpec spec, int offsetSeconds);
+    QDateTime(QDate date, QTime time, Qt::TimeSpec spec = Qt::LocalTime, int offsetSeconds = 0);
 #if QT_CONFIG(timezone)
-    QDateTime(const QDate &date, const QTime &time, const QTimeZone &timeZone);
+    QDateTime(QDate date, QTime time, const QTimeZone &timeZone);
 #endif // timezone
     QDateTime(const QDateTime &other) noexcept;
     QDateTime(QDateTime &&other) noexcept;
@@ -326,8 +324,8 @@ public:
     qint64 toMSecsSinceEpoch() const;
     qint64 toSecsSinceEpoch() const;
 
-    void setDate(const QDate &date); // ### Qt 6: plain QDate
-    void setTime(const QTime &time);
+    void setDate(QDate date);
+    void setTime(QTime time);
     void setTimeSpec(Qt::TimeSpec spec);
     void setOffsetFromUtc(int offsetSeconds);
 #if QT_CONFIG(timezone)
@@ -433,25 +431,25 @@ private:
 Q_DECLARE_SHARED(QDateTime)
 
 #ifndef QT_NO_DATASTREAM
-Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, const QDate &);
+Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, QDate);
 Q_CORE_EXPORT QDataStream &operator>>(QDataStream &, QDate &);
-Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, const QTime &);
+Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, QTime);
 Q_CORE_EXPORT QDataStream &operator>>(QDataStream &, QTime &);
 Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, const QDateTime &);
 Q_CORE_EXPORT QDataStream &operator>>(QDataStream &, QDateTime &);
 #endif // QT_NO_DATASTREAM
 
 #if !defined(QT_NO_DEBUG_STREAM) && QT_CONFIG(datestring)
-Q_CORE_EXPORT QDebug operator<<(QDebug, const QDate &);
-Q_CORE_EXPORT QDebug operator<<(QDebug, const QTime &);
+Q_CORE_EXPORT QDebug operator<<(QDebug, QDate);
+Q_CORE_EXPORT QDebug operator<<(QDebug, QTime);
 Q_CORE_EXPORT QDebug operator<<(QDebug, const QDateTime &);
 #endif
 
 // QDateTime is not noexcept for now -- to be revised once
 // timezone and calendaring support is added
 Q_CORE_EXPORT uint qHash(const QDateTime &key, uint seed = 0);
-Q_CORE_EXPORT uint qHash(const QDate &key, uint seed = 0) noexcept;
-Q_CORE_EXPORT uint qHash(const QTime &key, uint seed = 0) noexcept;
+Q_CORE_EXPORT uint qHash(QDate key, uint seed = 0) noexcept;
+Q_CORE_EXPORT uint qHash(QTime key, uint seed = 0) noexcept;
 
 QT_END_NAMESPACE
 
diff --git a/src/corelib/time/qdatetime_p.h b/src/corelib/time/qdatetime_p.h
index f4f00a8b9b..c500b023c4 100644
--- a/src/corelib/time/qdatetime_p.h
+++ b/src/corelib/time/qdatetime_p.h
@@ -110,11 +110,11 @@ public:
         DaylightMask        = SetToStandardTime | SetToDaylightTime
     };
 
-    static QDateTime::Data create(const QDate &toDate, const QTime &toTime, Qt::TimeSpec toSpec,
+    static QDateTime::Data create(QDate toDate, QTime toTime, Qt::TimeSpec toSpec,
                                   int offsetSeconds);
 
 #if QT_CONFIG(timezone)
-    static QDateTime::Data create(const QDate &toDate, const QTime &toTime, const QTimeZone & timeZone);
+    static QDateTime::Data create(QDate toDate, QTime toTime, const QTimeZone & timeZone);
 #endif // timezone
 
     StatusFlags m_status = StatusFlag(Qt::LocalTime << TimeSpecShift);
diff --git a/src/printsupport/kernel/qcups.cpp b/src/printsupport/kernel/qcups.cpp
index 0fc8cdd1b7..ab9b2889e2 100644
--- a/src/printsupport/kernel/qcups.cpp
+++ b/src/printsupport/kernel/qcups.cpp
@@ -167,7 +167,7 @@ ppd_option_t *QCUPSSupport::findPpdOption(const char *optionName, QPrintDevice *
     return nullptr;
 }
 
-void QCUPSSupport::setJobHold(QPrinter *printer, const JobHoldUntil jobHold, const QTime &holdUntilTime)
+void QCUPSSupport::setJobHold(QPrinter *printer, const JobHoldUntil jobHold, QTime holdUntilTime)
 {
     const QString jobHoldUntilArgument = jobHoldToString(jobHold, holdUntilTime);
     if (!jobHoldUntilArgument.isEmpty()) {
diff --git a/src/printsupport/kernel/qcups_p.h b/src/printsupport/kernel/qcups_p.h
index 57ec281383..4d72230b90 100644
--- a/src/printsupport/kernel/qcups_p.h
+++ b/src/printsupport/kernel/qcups_p.h
@@ -137,7 +137,7 @@ public:
     static void clearCupsOption(QPrinter *printer, const QString &option);
     static void clearCupsOptions(QPrinter *printer);
 
-    static void setJobHold(QPrinter *printer, const JobHoldUntil jobHold = NoHold, const QTime &holdUntilTime = QTime());
+    static void setJobHold(QPrinter *printer, const JobHoldUntil jobHold = NoHold, QTime holdUntilTime = QTime());
     static void setJobBilling(QPrinter *printer, const QString &jobBilling = QString());
     static void setJobPriority(QPrinter *printer, int priority = 50);
     static void setBannerPages(QPrinter *printer, const BannerPage startBannerPage, const BannerPage endBannerPage);
@@ -159,7 +159,7 @@ public:
 
     struct JobHoldUntilWithTime
     {
-        JobHoldUntilWithTime(JobHoldUntil jh = NoHold, const QTime &t = QTime())
+        JobHoldUntilWithTime(JobHoldUntil jh = NoHold, QTime t = QTime())
             : jobHold(jh), time(t) {}
 
         JobHoldUntil jobHold;
diff --git a/src/printsupport/widgets/qcupsjobwidget.cpp b/src/printsupport/widgets/qcupsjobwidget.cpp
index 6d9e7432bc..43729d1fc6 100644
--- a/src/printsupport/widgets/qcupsjobwidget.cpp
+++ b/src/printsupport/widgets/qcupsjobwidget.cpp
@@ -138,7 +138,7 @@ void QCupsJobWidget::initJobHold()
     toggleJobHoldTime();
 }
 
-void QCupsJobWidget::setJobHold(QCUPSSupport::JobHoldUntil jobHold, const QTime &holdUntilTime)
+void QCupsJobWidget::setJobHold(QCUPSSupport::JobHoldUntil jobHold, QTime holdUntilTime)
 {
     if (jobHold == QCUPSSupport::SpecificTime && holdUntilTime.isNull()) {
         jobHold = QCUPSSupport::NoHold;
diff --git a/src/printsupport/widgets/qcupsjobwidget_p.h b/src/printsupport/widgets/qcupsjobwidget_p.h
index 42da9c7580..d73f116a69 100644
--- a/src/printsupport/widgets/qcupsjobwidget_p.h
+++ b/src/printsupport/widgets/qcupsjobwidget_p.h
@@ -83,7 +83,7 @@ private Q_SLOTS:
 
 private:
 
-    void setJobHold(QCUPSSupport::JobHoldUntil jobHold = QCUPSSupport::NoHold, const QTime &holdUntilTime = QTime());
+    void setJobHold(QCUPSSupport::JobHoldUntil jobHold = QCUPSSupport::NoHold, QTime holdUntilTime = QTime());
     QCUPSSupport::JobHoldUntil jobHold() const;
     QTime jobHoldTime() const;
 
diff --git a/src/widgets/styles/qstyleanimation.cpp b/src/widgets/styles/qstyleanimation.cpp
index 1c1158ab10..ce3b6ce34a 100644
--- a/src/widgets/styles/qstyleanimation.cpp
+++ b/src/widgets/styles/qstyleanimation.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtWidgets module of the Qt Toolkit.
@@ -87,7 +87,7 @@ QTime QStyleAnimation::startTime() const
     return _startTime;
 }
 
-void QStyleAnimation::setStartTime(const QTime &time)
+void QStyleAnimation::setStartTime(QTime time)
 {
     _startTime = time;
 }
diff --git a/src/widgets/styles/qstyleanimation_p.h b/src/widgets/styles/qstyleanimation_p.h
index d28fc6ebab..0971289756 100644
--- a/src/widgets/styles/qstyleanimation_p.h
+++ b/src/widgets/styles/qstyleanimation_p.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtWidgets module of the Qt Toolkit.
@@ -77,7 +77,7 @@ public:
     void setDelay(int delay);
 
     QTime startTime() const;
-    void setStartTime(const QTime &time);
+    void setStartTime(QTime time);
 
     enum FrameRate {
         DefaultFps,
diff --git a/src/widgets/widgets/qcalendarwidget.cpp b/src/widgets/widgets/qcalendarwidget.cpp
index 570ec72377..e7dddef766 100644
--- a/src/widgets/widgets/qcalendarwidget.cpp
+++ b/src/widgets/widgets/qcalendarwidget.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 QtWidgets module of the Qt Toolkit.
@@ -2311,7 +2311,7 @@ QSize QCalendarWidget::minimumSizeHint() const
     Paints the cell specified by the given \a date, using the given \a painter and \a rect.
 */
 
-void QCalendarWidget::paintCell(QPainter *painter, const QRect &rect, const QDate &date) const
+void QCalendarWidget::paintCell(QPainter *painter, QRect rect, QDate date) const
 {
     Q_D(const QCalendarWidget);
     d->m_delegate->paintCell(painter, rect, date);
@@ -2334,7 +2334,7 @@ QDate QCalendarWidget::selectedDate() const
     return d->m_model->m_date;
 }
 
-void QCalendarWidget::setSelectedDate(const QDate &date)
+void QCalendarWidget::setSelectedDate(QDate date)
 {
     Q_D(QCalendarWidget);
     if (d->m_model->m_date == date && date == d->getCurrentDate())
@@ -2543,7 +2543,7 @@ QDate QCalendarWidget::minimumDate() const
     return d->m_model->m_minimumDate;
 }
 
-void QCalendarWidget::setMinimumDate(const QDate &date)
+void QCalendarWidget::setMinimumDate(QDate date)
 {
     Q_D(QCalendarWidget);
     if (!date.isValid() || d->m_model->m_minimumDate == date)
@@ -2594,7 +2594,7 @@ QDate QCalendarWidget::maximumDate() const
     return d->m_model->m_maximumDate;
 }
 
-void QCalendarWidget::setMaximumDate(const QDate &date)
+void QCalendarWidget::setMaximumDate(QDate date)
 {
     Q_D(QCalendarWidget);
     if (!date.isValid() || d->m_model->m_maximumDate == date)
@@ -2632,7 +2632,7 @@ void QCalendarWidget::setMaximumDate(const QDate &date)
     \sa setMinimumDate(), setMaximumDate()
 */
 
-void QCalendarWidget::setDateRange(const QDate &min, const QDate &max)
+void QCalendarWidget::setDateRange(QDate min, QDate max)
 {
     Q_D(QCalendarWidget);
     if (d->m_model->m_minimumDate == min && d->m_model->m_maximumDate == max)
@@ -2900,7 +2900,7 @@ QMap<QDate, QTextCharFormat> QCalendarWidget::dateTextFormat() const
     Returns a QTextCharFormat for \a date. The char format can be be
     empty if the date is not renderd specially.
 */
-QTextCharFormat QCalendarWidget::dateTextFormat(const QDate &date) const
+QTextCharFormat QCalendarWidget::dateTextFormat(QDate date) const
 {
     Q_D(const QCalendarWidget);
     return d->m_model->m_dateFormats.value(date);
@@ -2911,7 +2911,7 @@ QTextCharFormat QCalendarWidget::dateTextFormat(const QDate &date) const
 
     If \a date is null, all date formats are cleared.
 */
-void QCalendarWidget::setDateTextFormat(const QDate &date, const QTextCharFormat &format)
+void QCalendarWidget::setDateTextFormat(QDate date, const QTextCharFormat &format)
 {
     Q_D(QCalendarWidget);
     if (date.isNull())
@@ -2989,7 +2989,7 @@ void QCalendarWidget::setDateEditAcceptDelay(int delay)
 
     \sa updateCells(), yearShown(), monthShown()
 */
-void QCalendarWidget::updateCell(const QDate &date)
+void QCalendarWidget::updateCell(QDate date)
 {
     if (Q_UNLIKELY(!date.isValid())) {
         qWarning("QCalendarWidget::updateCell: Invalid date");
@@ -3048,7 +3048,7 @@ void QCalendarWidget::updateCells()
 */
 
 /*!
-    \fn void QCalendarWidget::activated(const QDate &date)
+    \fn void QCalendarWidget::activated(QDate date)
 
     This signal is emitted whenever the user presses the Return or
     Enter key or double-clicks a \a date in the calendar
@@ -3056,7 +3056,7 @@ void QCalendarWidget::updateCells()
 */
 
 /*!
-    \fn void QCalendarWidget::clicked(const QDate &date)
+    \fn void QCalendarWidget::clicked(QDate date)
 
     This signal is emitted when a mouse button is clicked. The date
     the mouse was clicked on is specified by \a date. The signal is
diff --git a/src/widgets/widgets/qcalendarwidget.h b/src/widgets/widgets/qcalendarwidget.h
index 08825a0ff3..70cf574a81 100644
--- a/src/widgets/widgets/qcalendarwidget.h
+++ b/src/widgets/widgets/qcalendarwidget.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2018 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtWidgets module of the Qt Toolkit.
@@ -101,10 +101,10 @@ public:
     int monthShown() const;
 
     QDate minimumDate() const;
-    void setMinimumDate(const QDate &date);
+    void setMinimumDate(QDate date);
 
     QDate maximumDate() const;
-    void setMaximumDate(const QDate &date);
+    void setMaximumDate(QDate date);
 
     Qt::DayOfWeek firstDayOfWeek() const;
     void setFirstDayOfWeek(Qt::DayOfWeek dayOfWeek);
@@ -131,8 +131,8 @@ public:
     void setWeekdayTextFormat(Qt::DayOfWeek dayOfWeek, const QTextCharFormat &format);
 
     QMap<QDate, QTextCharFormat> dateTextFormat() const;
-    QTextCharFormat dateTextFormat(const QDate &date) const;
-    void setDateTextFormat(const QDate &date, const QTextCharFormat &format);
+    QTextCharFormat dateTextFormat(QDate date) const;
+    void setDateTextFormat(QDate date, const QTextCharFormat &format);
 
     bool isDateEditEnabled() const;
     void setDateEditEnabled(bool enable);
@@ -147,13 +147,13 @@ protected:
     void resizeEvent(QResizeEvent * event) override;
     void keyPressEvent(QKeyEvent * event) override;
 
-    virtual void paintCell(QPainter *painter, const QRect &rect, const QDate &date) const;
-    void updateCell(const QDate &date);
+    virtual void paintCell(QPainter *painter, QRect rect, QDate date) const;
+    void updateCell(QDate date);
     void updateCells();
 
 public Q_SLOTS:
-    void setSelectedDate(const QDate &date);
-    void setDateRange(const QDate &min, const QDate &max);
+    void setSelectedDate(QDate date);
+    void setDateRange(QDate min, QDate max);
     void setCurrentPage(int year, int month);
     void setGridVisible(bool show);
     void setNavigationBarVisible(bool visible);
@@ -166,17 +166,17 @@ public Q_SLOTS:
 
 Q_SIGNALS:
     void selectionChanged();
-    void clicked(const QDate &date);
-    void activated(const QDate &date);
+    void clicked(QDate date);
+    void activated(QDate date);
     void currentPageChanged(int year, int month);
 
 private:
     Q_DECLARE_PRIVATE(QCalendarWidget)
     Q_DISABLE_COPY(QCalendarWidget)
 
-    Q_PRIVATE_SLOT(d_func(), void _q_slotShowDate(const QDate &date))
-    Q_PRIVATE_SLOT(d_func(), void _q_slotChangeDate(const QDate &date))
-    Q_PRIVATE_SLOT(d_func(), void _q_slotChangeDate(const QDate &date, bool changeMonth))
+    Q_PRIVATE_SLOT(d_func(), void _q_slotShowDate(QDate date))
+    Q_PRIVATE_SLOT(d_func(), void _q_slotChangeDate(QDate date))
+    Q_PRIVATE_SLOT(d_func(), void _q_slotChangeDate(QDate date, bool changeMonth))
     Q_PRIVATE_SLOT(d_func(), void _q_editingFinished())
     Q_PRIVATE_SLOT(d_func(), void _q_prevMonthClicked())
     Q_PRIVATE_SLOT(d_func(), void _q_nextMonthClicked())
diff --git a/src/widgets/widgets/qdatetimeedit.cpp b/src/widgets/widgets/qdatetimeedit.cpp
index 4880b5ee46..48588b1e8e 100644
--- a/src/widgets/widgets/qdatetimeedit.cpp
+++ b/src/widgets/widgets/qdatetimeedit.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 QtWidgets module of the Qt Toolkit.
@@ -133,14 +133,14 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-  \fn void QDateTimeEdit::timeChanged(const QTime &time)
+  \fn void QDateTimeEdit::timeChanged(QTime time)
 
   This signal is emitted whenever the time is changed. The new time
   is passed in \a time.
 */
 
 /*!
-  \fn void QDateTimeEdit::dateChanged(const QDate &date)
+  \fn void QDateTimeEdit::dateChanged(QDate date)
 
   This signal is emitted whenever the date is changed. The new date
   is passed in \a date.
@@ -171,13 +171,13 @@ QDateTimeEdit::QDateTimeEdit(const QDateTime &datetime, QWidget *parent)
 }
 
 /*!
-  \fn QDateTimeEdit::QDateTimeEdit(const QDate &date, QWidget *parent)
+  \fn QDateTimeEdit::QDateTimeEdit(QDate date, QWidget *parent)
 
   Constructs an empty date time editor with a \a parent.
   The value is set to \a date.
 */
 
-QDateTimeEdit::QDateTimeEdit(const QDate &date, QWidget *parent)
+QDateTimeEdit::QDateTimeEdit(QDate date, QWidget *parent)
     : QAbstractSpinBox(*new QDateTimeEditPrivate, parent)
 {
     Q_D(QDateTimeEdit);
@@ -185,13 +185,13 @@ QDateTimeEdit::QDateTimeEdit(const QDate &date, QWidget *parent)
 }
 
 /*!
-  \fn QDateTimeEdit::QDateTimeEdit(const QTime &time, QWidget *parent)
+  \fn QDateTimeEdit::QDateTimeEdit(QTime time, QWidget *parent)
 
   Constructs an empty date time editor with a \a parent.
   The value is set to \a time.
 */
 
-QDateTimeEdit::QDateTimeEdit(const QTime &time, QWidget *parent)
+QDateTimeEdit::QDateTimeEdit(QTime time, QWidget *parent)
     : QAbstractSpinBox(*new QDateTimeEditPrivate, parent)
 {
     Q_D(QDateTimeEdit);
@@ -283,7 +283,7 @@ QDate QDateTimeEdit::date() const
     return d->value.toDate();
 }
 
-void QDateTimeEdit::setDate(const QDate &date)
+void QDateTimeEdit::setDate(QDate date)
 {
     Q_D(QDateTimeEdit);
     if (date.isValid()) {
@@ -320,7 +320,7 @@ QTime QDateTimeEdit::time() const
     return d->value.toTime();
 }
 
-void QDateTimeEdit::setTime(const QTime &time)
+void QDateTimeEdit::setTime(QTime time)
 {
     Q_D(QDateTimeEdit);
     if (time.isValid()) {
@@ -483,7 +483,7 @@ QDate QDateTimeEdit::minimumDate() const
     return d->minimum.toDate();
 }
 
-void QDateTimeEdit::setMinimumDate(const QDate &min)
+void QDateTimeEdit::setMinimumDate(QDate min)
 {
     Q_D(QDateTimeEdit);
     if (min.isValid() && min >= QDATETIMEEDIT_DATE_MIN) {
@@ -523,7 +523,7 @@ QDate QDateTimeEdit::maximumDate() const
     return d->maximum.toDate();
 }
 
-void QDateTimeEdit::setMaximumDate(const QDate &max)
+void QDateTimeEdit::setMaximumDate(QDate max)
 {
     Q_D(QDateTimeEdit);
     if (max.isValid())
@@ -560,7 +560,7 @@ QTime QDateTimeEdit::minimumTime() const
     return d->minimum.toTime();
 }
 
-void QDateTimeEdit::setMinimumTime(const QTime &min)
+void QDateTimeEdit::setMinimumTime(QTime min)
 {
     Q_D(QDateTimeEdit);
     if (min.isValid()) {
@@ -598,7 +598,7 @@ QTime QDateTimeEdit::maximumTime() const
     return d->maximum.toTime();
 }
 
-void QDateTimeEdit::setMaximumTime(const QTime &max)
+void QDateTimeEdit::setMaximumTime(QTime max)
 {
     Q_D(QDateTimeEdit);
     if (max.isValid()) {
@@ -634,7 +634,7 @@ void QDateTimeEdit::clearMaximumTime()
   \sa minimumDate, maximumDate, setDateTimeRange(), QDate::isValid()
 */
 
-void QDateTimeEdit::setDateRange(const QDate &min, const QDate &max)
+void QDateTimeEdit::setDateRange(QDate min, QDate max)
 {
     Q_D(QDateTimeEdit);
     if (min.isValid() && max.isValid()) {
@@ -668,7 +668,7 @@ void QDateTimeEdit::setDateRange(const QDate &min, const QDate &max)
   \sa minimumTime, maximumTime, setDateTimeRange(), QTime::isValid()
 */
 
-void QDateTimeEdit::setTimeRange(const QTime &min, const QTime &max)
+void QDateTimeEdit::setTimeRange(QTime min, QTime max)
 {
     Q_D(QDateTimeEdit);
     if (min.isValid() && max.isValid()) {
@@ -1588,7 +1588,7 @@ QTimeEdit::QTimeEdit(QWidget *parent)
   to \a time.
 */
 
-QTimeEdit::QTimeEdit(const QTime &time, QWidget *parent)
+QTimeEdit::QTimeEdit(QTime time, QWidget *parent)
     : QDateTimeEdit(time, QMetaType::QTime, parent)
 {
     connect(this, &QTimeEdit::timeChanged, this, &QTimeEdit::userTimeChanged);
@@ -1608,7 +1608,7 @@ QTimeEdit::~QTimeEdit()
 */
 
 /*!
-  \fn void QTimeEdit::userTimeChanged(const QTime &time)
+  \fn void QTimeEdit::userTimeChanged(QTime time)
 
   This signal only exists to fully implement the time Q_PROPERTY on the class.
   Normally timeChanged should be used instead.
@@ -1658,7 +1658,7 @@ QDateEdit::QDateEdit(QWidget *parent)
   to \a date.
 */
 
-QDateEdit::QDateEdit(const QDate &date, QWidget *parent)
+QDateEdit::QDateEdit(QDate date, QWidget *parent)
     : QDateTimeEdit(date, QMetaType::QDate, parent)
 {
     connect(this, &QDateEdit::dateChanged, this, &QDateEdit::userDateChanged);
@@ -1678,7 +1678,7 @@ QDateEdit::~QDateEdit()
 */
 
 /*!
-  \fn void QDateEdit::userDateChanged(const QDate &date)
+  \fn void QDateEdit::userDateChanged(QDate date)
 
   This signal only exists to fully implement the date Q_PROPERTY on the class.
   Normally dateChanged should be used instead.
diff --git a/src/widgets/widgets/qdatetimeedit.h b/src/widgets/widgets/qdatetimeedit.h
index 8905ad4a9c..aafdee1ea8 100644
--- a/src/widgets/widgets/qdatetimeedit.h
+++ b/src/widgets/widgets/qdatetimeedit.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtWidgets module of the Qt Toolkit.
@@ -95,8 +95,8 @@ public:
 
     explicit QDateTimeEdit(QWidget *parent = nullptr);
     explicit QDateTimeEdit(const QDateTime &dt, QWidget *parent = nullptr);
-    explicit QDateTimeEdit(const QDate &d, QWidget *parent = nullptr);
-    explicit QDateTimeEdit(const QTime &t, QWidget *parent = nullptr);
+    explicit QDateTimeEdit(QDate d, QWidget *parent = nullptr);
+    explicit QDateTimeEdit(QTime t, QWidget *parent = nullptr);
     ~QDateTimeEdit();
 
     QDateTime dateTime() const;
@@ -117,24 +117,24 @@ public:
     void setDateTimeRange(const QDateTime &min, const QDateTime &max);
 
     QDate minimumDate() const;
-    void setMinimumDate(const QDate &min);
+    void setMinimumDate(QDate min);
     void clearMinimumDate();
 
     QDate maximumDate() const;
-    void setMaximumDate(const QDate &max);
+    void setMaximumDate(QDate max);
     void clearMaximumDate();
 
-    void setDateRange(const QDate &min, const QDate &max);
+    void setDateRange(QDate min, QDate max);
 
     QTime minimumTime() const;
-    void setMinimumTime(const QTime &min);
+    void setMinimumTime(QTime min);
     void clearMinimumTime();
 
     QTime maximumTime() const;
-    void setMaximumTime(const QTime &max);
+    void setMaximumTime(QTime max);
     void clearMaximumTime();
 
-    void setTimeRange(const QTime &min, const QTime &max);
+    void setTimeRange(QTime min, QTime max);
 
     Sections displayedSections() const;
     Section currentSection() const;
@@ -170,13 +170,13 @@ public:
     bool event(QEvent *event) override;
 Q_SIGNALS:
     void dateTimeChanged(const QDateTime &dateTime);
-    void timeChanged(const QTime &time);
-    void dateChanged(const QDate &date);
+    void timeChanged(QTime time);
+    void dateChanged(QDate date);
 
 public Q_SLOTS:
     void setDateTime(const QDateTime &dateTime);
-    void setDate(const QDate &date);
-    void setTime(const QTime &time);
+    void setDate(QDate date);
+    void setTime(QTime time);
 
 protected:
     void keyPressEvent(QKeyEvent *event) override;
@@ -212,11 +212,11 @@ class Q_WIDGETS_EXPORT QTimeEdit : public QDateTimeEdit
     Q_PROPERTY(QTime time READ time WRITE setTime NOTIFY userTimeChanged USER true)
 public:
     explicit QTimeEdit(QWidget *parent = nullptr);
-    explicit QTimeEdit(const QTime &time, QWidget *parent = nullptr);
+    explicit QTimeEdit(QTime time, QWidget *parent = nullptr);
     ~QTimeEdit();
 
 Q_SIGNALS:
-    void userTimeChanged(const QTime &time);
+    void userTimeChanged(QTime time);
 };
 
 class Q_WIDGETS_EXPORT QDateEdit : public QDateTimeEdit
@@ -225,11 +225,11 @@ class Q_WIDGETS_EXPORT QDateEdit : public QDateTimeEdit
     Q_PROPERTY(QDate date READ date WRITE setDate NOTIFY userDateChanged USER true)
 public:
     explicit QDateEdit(QWidget *parent = nullptr);
-    explicit QDateEdit(const QDate &date, QWidget *parent = nullptr);
+    explicit QDateEdit(QDate date, QWidget *parent = nullptr);
     ~QDateEdit();
 
 Q_SIGNALS:
-    void userDateChanged(const QDate &date);
+    void userDateChanged(QDate date);
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QDateTimeEdit::Sections)