Replace Q_REQUIRED_RESULT with [[nodiscard]]

It was already used many places directly making the code inconsistent.

Change-Id: I3b14bc6c333640fb3ba33c71eba97e78c973e44b
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

10 files changed, 80 insertions, 93 deletions

diff --git a/src/corelib/tools/qarraydata.h b/src/corelib/tools/qarraydata.h
index 856a9521ad..c984f700be 100644
--- a/src/corelib/tools/qarraydata.h
+++ b/src/corelib/tools/qarraydata.h
@@ -115,13 +115,13 @@ struct Q_CORE_EXPORT QArrayData
         return result;
     }
 
-    Q_REQUIRED_RESULT
+    [[nodiscard]]
 #if defined(Q_CC_GNU)
     __attribute__((__malloc__))
 #endif
     static void *allocate(QArrayData **pdata, qsizetype objectSize, qsizetype alignment,
             qsizetype capacity, ArrayOptions options = DefaultAllocationFlags) noexcept;
-    Q_REQUIRED_RESULT static QPair<QArrayData *, void *> reallocateUnaligned(QArrayData *data, void *dataPointer,
+    [[nodiscard]] static QPair<QArrayData *, void *> reallocateUnaligned(QArrayData *data, void *dataPointer,
             qsizetype objectSize, qsizetype newCapacity, ArrayOptions newOptions = DefaultAllocationFlags) noexcept;
     static void deallocate(QArrayData *data, qsizetype objectSize,
             qsizetype alignment) noexcept;
@@ -208,7 +208,7 @@ struct QTypedArrayData
 
     class AlignmentDummy { QArrayData header; T data; };
 
-    Q_REQUIRED_RESULT static QPair<QTypedArrayData *, T *> allocate(qsizetype capacity,
+    [[nodiscard]] static QPair<QTypedArrayData *, T *> allocate(qsizetype capacity,
             ArrayOptions options = DefaultAllocationFlags)
     {
         static_assert(sizeof(QTypedArrayData) == sizeof(QArrayData));
diff --git a/src/corelib/tools/qarraydatapointer.h b/src/corelib/tools/qarraydatapointer.h
index ad5acdb7fd..f92eb78a6f 100644
--- a/src/corelib/tools/qarraydatapointer.h
+++ b/src/corelib/tools/qarraydatapointer.h
@@ -243,7 +243,7 @@ public:
     }
 
 private:
-    Q_REQUIRED_RESULT QPair<Data *, T *> clone(QArrayData::ArrayOptions options) const
+    [[nodiscard]] QPair<Data *, T *> clone(QArrayData::ArrayOptions options) const
     {
         QPair<Data *, T *> pair = Data::allocate(detachCapacity(size), options);
         QArrayDataPointer copy(pair.first, pair.second, 0);
diff --git a/src/corelib/tools/qduplicatetracker_p.h b/src/corelib/tools/qduplicatetracker_p.h
index baf21bfd12..e5bb11793a 100644
--- a/src/corelib/tools/qduplicatetracker_p.h
+++ b/src/corelib/tools/qduplicatetracker_p.h
@@ -75,7 +75,7 @@ class QDuplicateTracker {
 public:
     QDuplicateTracker() = default;
     void reserve(int n) { set.reserve(n); }
-    Q_REQUIRED_RESULT bool hasSeen(const T &s)
+    [[nodiscard]] bool hasSeen(const T &s)
     {
         bool inserted;
 #ifdef __cpp_lib_memory_resource
@@ -87,7 +87,7 @@ public:
 #endif
         return !inserted;
     }
-    Q_REQUIRED_RESULT bool hasSeen(T &&s)
+    [[nodiscard]] bool hasSeen(T &&s)
     {
         bool inserted;
 #ifdef __cpp_lib_memory_resource
diff --git a/src/corelib/tools/qline.h b/src/corelib/tools/qline.h
index c3fb2fd5f5..adef545d86 100644
--- a/src/corelib/tools/qline.h
+++ b/src/corelib/tools/qline.h
@@ -75,10 +75,10 @@ public:
     inline void translate(const QPoint &p);
     inline void translate(int dx, int dy);
 
-    Q_REQUIRED_RESULT constexpr inline QLine translated(const QPoint &p) const;
-    Q_REQUIRED_RESULT constexpr inline QLine translated(int dx, int dy) const;
+    [[nodiscard]] constexpr inline QLine translated(const QPoint &p) const;
+    [[nodiscard]] constexpr inline QLine translated(int dx, int dy) const;
 
-    Q_REQUIRED_RESULT constexpr inline QPoint center() const;
+    [[nodiscard]] constexpr inline QPoint center() const;
 
     inline void setP1(const QPoint &p1);
     inline void setP2(const QPoint &p2);
@@ -225,7 +225,7 @@ public:
     constexpr inline QLineF(qreal x1, qreal y1, qreal x2, qreal y2);
     constexpr inline QLineF(const QLine &line) : pt1(line.p1()), pt2(line.p2()) { }
 
-    Q_REQUIRED_RESULT static QLineF fromPolar(qreal length, qreal angle);
+    [[nodiscard]] static QLineF fromPolar(qreal length, qreal angle);
 
     constexpr bool isNull() const;
 
@@ -249,8 +249,8 @@ public:
 
     qreal angleTo(const QLineF &l) const;
 
-    Q_REQUIRED_RESULT QLineF unitVector() const;
-    Q_REQUIRED_RESULT constexpr inline QLineF normalVector() const;
+    [[nodiscard]] QLineF unitVector() const;
+    [[nodiscard]] constexpr inline QLineF normalVector() const;
 
     IntersectionType intersects(const QLineF &l, QPointF *intersectionPoint = nullptr) const;
 
@@ -258,10 +258,10 @@ public:
     inline void translate(const QPointF &p);
     inline void translate(qreal dx, qreal dy);
 
-    Q_REQUIRED_RESULT constexpr inline QLineF translated(const QPointF &p) const;
-    Q_REQUIRED_RESULT constexpr inline QLineF translated(qreal dx, qreal dy) const;
+    [[nodiscard]] constexpr inline QLineF translated(const QPointF &p) const;
+    [[nodiscard]] constexpr inline QLineF translated(qreal dx, qreal dy) const;
 
-    Q_REQUIRED_RESULT constexpr inline QPointF center() const;
+    [[nodiscard]] constexpr inline QPointF center() const;
 
     inline void setP1(const QPointF &p1);
     inline void setP2(const QPointF &p2);
diff --git a/src/corelib/tools/qpoint.h b/src/corelib/tools/qpoint.h
index e854e77198..dd0f177fa6 100644
--- a/src/corelib/tools/qpoint.h
+++ b/src/corelib/tools/qpoint.h
@@ -96,7 +96,7 @@ public:
     friend constexpr inline const QPoint operator/(const QPoint &, qreal);
 
 #if defined(Q_OS_DARWIN) || defined(Q_QDOC)
-    Q_REQUIRED_RESULT Q_CORE_EXPORT CGPoint toCGPoint() const noexcept;
+    [[nodiscard]] Q_CORE_EXPORT CGPoint toCGPoint() const noexcept;
 #endif
 
 private:
@@ -261,8 +261,8 @@ public:
     constexpr QPoint toPoint() const;
 
 #if defined(Q_OS_DARWIN) || defined(Q_QDOC)
-    Q_REQUIRED_RESULT Q_CORE_EXPORT static QPointF fromCGPoint(CGPoint point) noexcept;
-    Q_REQUIRED_RESULT Q_CORE_EXPORT CGPoint toCGPoint() const noexcept;
+    [[nodiscard]] Q_CORE_EXPORT static QPointF fromCGPoint(CGPoint point) noexcept;
+    [[nodiscard]] Q_CORE_EXPORT CGPoint toCGPoint() const noexcept;
 #endif
 
 private:
diff --git a/src/corelib/tools/qrect.h b/src/corelib/tools/qrect.h
index 5deb220b2d..dbabc4eb0b 100644
--- a/src/corelib/tools/qrect.h
+++ b/src/corelib/tools/qrect.h
@@ -71,7 +71,7 @@ public:
     constexpr inline int top() const noexcept;
     constexpr inline int right() const noexcept;
     constexpr inline int bottom() const noexcept;
-    Q_REQUIRED_RESULT QRect normalized() const noexcept;
+    [[nodiscard]] QRect normalized() const noexcept;
 
     constexpr inline int x() const noexcept;
     constexpr inline int y() const noexcept;
@@ -105,9 +105,9 @@ public:
 
     constexpr inline void translate(int dx, int dy) noexcept;
     constexpr inline void translate(const QPoint &p) noexcept;
-    Q_REQUIRED_RESULT constexpr inline QRect translated(int dx, int dy) const noexcept;
-    Q_REQUIRED_RESULT constexpr inline QRect translated(const QPoint &p) const noexcept;
-    Q_REQUIRED_RESULT constexpr inline QRect transposed() const noexcept;
+    [[nodiscard]] constexpr inline QRect translated(int dx, int dy) const noexcept;
+    [[nodiscard]] constexpr inline QRect translated(const QPoint &p) const noexcept;
+    [[nodiscard]] constexpr inline QRect transposed() const noexcept;
 
     constexpr inline void moveTo(int x, int t) noexcept;
     constexpr inline void moveTo(const QPoint &p) noexcept;
@@ -119,7 +119,7 @@ public:
     constexpr inline void getCoords(int *x1, int *y1, int *x2, int *y2) const;
 
     constexpr inline void adjust(int x1, int y1, int x2, int y2) noexcept;
-    Q_REQUIRED_RESULT constexpr inline QRect adjusted(int x1, int y1, int x2, int y2) const noexcept;
+    [[nodiscard]] constexpr inline QRect adjusted(int x1, int y1, int x2, int y2) const noexcept;
 
     constexpr inline QSize size() const noexcept;
     constexpr inline int width() const noexcept;
@@ -137,8 +137,8 @@ public:
     bool contains(const QPoint &p, bool proper=false) const noexcept;
     inline bool contains(int x, int y) const noexcept;
     inline bool contains(int x, int y, bool proper) const noexcept;
-    Q_REQUIRED_RESULT inline QRect united(const QRect &other) const noexcept;
-    Q_REQUIRED_RESULT inline QRect intersected(const QRect &other) const noexcept;
+    [[nodiscard]] inline QRect united(const QRect &other) const noexcept;
+    [[nodiscard]] inline QRect intersected(const QRect &other) const noexcept;
     bool intersects(const QRect &r) const noexcept;
 
     constexpr inline QRect marginsAdded(const QMargins &margins) const noexcept;
@@ -146,14 +146,14 @@ public:
     constexpr inline QRect &operator+=(const QMargins &margins) noexcept;
     constexpr inline QRect &operator-=(const QMargins &margins) noexcept;
 
-    Q_REQUIRED_RESULT static constexpr inline QRect span(const QPoint &p1, const QPoint &p2) noexcept;
+    [[nodiscard]] static constexpr inline QRect span(const QPoint &p1, const QPoint &p2) noexcept;
 
     friend constexpr inline bool operator==(const QRect &, const QRect &) noexcept;
     friend constexpr inline bool operator!=(const QRect &, const QRect &) noexcept;
     friend constexpr inline size_t qHash(const QRect &, size_t) noexcept;
 
 #if defined(Q_OS_DARWIN) || defined(Q_QDOC)
-    Q_REQUIRED_RESULT CGRect toCGRect() const noexcept;
+    [[nodiscard]] CGRect toCGRect() const noexcept;
 #endif
 
 private:
@@ -530,7 +530,7 @@ public:
     constexpr inline bool isNull() const noexcept;
     constexpr inline bool isEmpty() const noexcept;
     constexpr inline bool isValid() const noexcept;
-    Q_REQUIRED_RESULT QRectF normalized() const noexcept;
+    [[nodiscard]] QRectF normalized() const noexcept;
 
     constexpr inline qreal left() const noexcept { return xp; }
     constexpr inline qreal top() const noexcept { return yp; }
@@ -570,10 +570,10 @@ public:
     constexpr inline void translate(qreal dx, qreal dy) noexcept;
     constexpr inline void translate(const QPointF &p) noexcept;
 
-    Q_REQUIRED_RESULT constexpr inline QRectF translated(qreal dx, qreal dy) const noexcept;
-    Q_REQUIRED_RESULT constexpr inline QRectF translated(const QPointF &p) const noexcept;
+    [[nodiscard]] constexpr inline QRectF translated(qreal dx, qreal dy) const noexcept;
+    [[nodiscard]] constexpr inline QRectF translated(const QPointF &p) const noexcept;
 
-    Q_REQUIRED_RESULT constexpr inline QRectF transposed() const noexcept;
+    [[nodiscard]] constexpr inline QRectF transposed() const noexcept;
 
     constexpr inline void moveTo(qreal x, qreal y) noexcept;
     constexpr inline void moveTo(const QPointF &p) noexcept;
@@ -585,7 +585,7 @@ public:
     constexpr inline void getCoords(qreal *x1, qreal *y1, qreal *x2, qreal *y2) const;
 
     constexpr inline void adjust(qreal x1, qreal y1, qreal x2, qreal y2) noexcept;
-    Q_REQUIRED_RESULT constexpr inline QRectF adjusted(qreal x1, qreal y1, qreal x2, qreal y2) const noexcept;
+    [[nodiscard]] constexpr inline QRectF adjusted(qreal x1, qreal y1, qreal x2, qreal y2) const noexcept;
 
     constexpr inline QSizeF size() const noexcept;
     constexpr inline qreal width() const noexcept;
@@ -602,8 +602,8 @@ public:
     bool contains(const QRectF &r) const noexcept;
     bool contains(const QPointF &p) const noexcept;
     inline bool contains(qreal x, qreal y) const noexcept;
-    Q_REQUIRED_RESULT inline QRectF united(const QRectF &other) const noexcept;
-    Q_REQUIRED_RESULT inline QRectF intersected(const QRectF &other) const noexcept;
+    [[nodiscard]] inline QRectF united(const QRectF &other) const noexcept;
+    [[nodiscard]] inline QRectF intersected(const QRectF &other) const noexcept;
     bool intersects(const QRectF &r) const noexcept;
 
     constexpr inline QRectF marginsAdded(const QMarginsF &margins) const noexcept;
@@ -614,12 +614,12 @@ public:
     friend constexpr inline bool operator==(const QRectF &, const QRectF &) noexcept;
     friend constexpr inline bool operator!=(const QRectF &, const QRectF &) noexcept;
 
-    Q_REQUIRED_RESULT constexpr inline QRect toRect() const noexcept;
-    Q_REQUIRED_RESULT QRect toAlignedRect() const noexcept;
+    [[nodiscard]] constexpr inline QRect toRect() const noexcept;
+    [[nodiscard]] QRect toAlignedRect() const noexcept;
 
 #if defined(Q_OS_DARWIN) || defined(Q_QDOC)
-    Q_REQUIRED_RESULT static QRectF fromCGRect(CGRect rect) noexcept;
-    Q_REQUIRED_RESULT CGRect toCGRect() const noexcept;
+    [[nodiscard]] static QRectF fromCGRect(CGRect rect) noexcept;
+    [[nodiscard]] CGRect toCGRect() const noexcept;
 #endif
 
 private:
diff --git a/src/corelib/tools/qscopedvaluerollback.h b/src/corelib/tools/qscopedvaluerollback.h
index d076b67330..9b14308ec2 100644
--- a/src/corelib/tools/qscopedvaluerollback.h
+++ b/src/corelib/tools/qscopedvaluerollback.h
@@ -45,11 +45,7 @@
 QT_BEGIN_NAMESPACE
 
 template <typename T>
-class
-#if QT_HAS_CPP_ATTRIBUTE(nodiscard) && __cplusplus >= 201703L
-[[nodiscard]]
-#endif
-QScopedValueRollback
+class [[nodiscard]] QScopedValueRollback
 {
 public:
     explicit constexpr QScopedValueRollback(T &var)
diff --git a/src/corelib/tools/qscopeguard.h b/src/corelib/tools/qscopeguard.h
index d288fd63fc..8270f41a2e 100644
--- a/src/corelib/tools/qscopeguard.h
+++ b/src/corelib/tools/qscopeguard.h
@@ -49,13 +49,7 @@
 QT_BEGIN_NAMESPACE
 
 template <typename F>
-class
-#if __has_cpp_attribute(nodiscard)
-// Q_REQUIRED_RESULT can be defined as __warn_unused_result__ or as [[nodiscard]]
-// but the 1st one has some limitations for example can be placed only on functions.
-Q_REQUIRED_RESULT
-#endif
-QScopeGuard
+class [[nodiscard]] QScopeGuard
 {
 public:
     explicit QScopeGuard(F &&f) noexcept
@@ -98,10 +92,7 @@ template <typename F> QScopeGuard(F(&)()) -> QScopeGuard<F(*)()>;
 
 //! [qScopeGuard]
 template <typename F>
-#if __has_cpp_attribute(nodiscard)
-Q_REQUIRED_RESULT
-#endif
-QScopeGuard<typename std::decay<F>::type> qScopeGuard(F &&f)
+[[nodiscard]] QScopeGuard<typename std::decay<F>::type> qScopeGuard(F &&f)
 {
     return QScopeGuard<typename std::decay<F>::type>(std::forward<F>(f));
 }
diff --git a/src/corelib/tools/qsize.h b/src/corelib/tools/qsize.h
index d2598afbea..d89d9e0426 100644
--- a/src/corelib/tools/qsize.h
+++ b/src/corelib/tools/qsize.h
@@ -66,19 +66,19 @@ public:
     constexpr inline void setWidth(int w) noexcept;
     constexpr inline void setHeight(int h) noexcept;
     void transpose() noexcept;
-    Q_REQUIRED_RESULT constexpr inline QSize transposed() const noexcept;
+    [[nodiscard]] constexpr inline QSize transposed() const noexcept;
 
     inline void scale(int w, int h, Qt::AspectRatioMode mode) noexcept;
     inline void scale(const QSize &s, Qt::AspectRatioMode mode) noexcept;
-    Q_REQUIRED_RESULT QSize scaled(int w, int h, Qt::AspectRatioMode mode) const noexcept;
-    Q_REQUIRED_RESULT QSize scaled(const QSize &s, Qt::AspectRatioMode mode) const noexcept;
+    [[nodiscard]] QSize scaled(int w, int h, Qt::AspectRatioMode mode) const noexcept;
+    [[nodiscard]] QSize scaled(const QSize &s, Qt::AspectRatioMode mode) const noexcept;
 
-    Q_REQUIRED_RESULT constexpr inline QSize expandedTo(const QSize &) const noexcept;
-    Q_REQUIRED_RESULT constexpr inline QSize boundedTo(const QSize &) const noexcept;
+    [[nodiscard]] constexpr inline QSize expandedTo(const QSize &) const noexcept;
+    [[nodiscard]] constexpr inline QSize boundedTo(const QSize &) const noexcept;
 
-    Q_REQUIRED_RESULT constexpr QSize grownBy(QMargins m) const noexcept
+    [[nodiscard]] constexpr QSize grownBy(QMargins m) const noexcept
     { return {width() + m.left() + m.right(), height() + m.top() + m.bottom()}; }
-    Q_REQUIRED_RESULT constexpr QSize shrunkBy(QMargins m) const noexcept
+    [[nodiscard]] constexpr QSize shrunkBy(QMargins m) const noexcept
     { return {width() - m.left() - m.right(), height() - m.top() - m.bottom()}; }
 
     constexpr inline int &rwidth() noexcept;
@@ -99,7 +99,7 @@ public:
     friend inline const QSize operator/(const QSize &, qreal);
 
 #if defined(Q_OS_DARWIN) || defined(Q_QDOC)
-    Q_REQUIRED_RESULT CGSize toCGSize() const noexcept;
+    [[nodiscard]] CGSize toCGSize() const noexcept;
 #endif
 
 private:
@@ -239,19 +239,19 @@ public:
     constexpr inline void setWidth(qreal w) noexcept;
     constexpr inline void setHeight(qreal h) noexcept;
     void transpose() noexcept;
-    Q_REQUIRED_RESULT constexpr inline QSizeF transposed() const noexcept;
+    [[nodiscard]] constexpr inline QSizeF transposed() const noexcept;
 
     inline void scale(qreal w, qreal h, Qt::AspectRatioMode mode) noexcept;
     inline void scale(const QSizeF &s, Qt::AspectRatioMode mode) noexcept;
-    Q_REQUIRED_RESULT QSizeF scaled(qreal w, qreal h, Qt::AspectRatioMode mode) const noexcept;
-    Q_REQUIRED_RESULT QSizeF scaled(const QSizeF &s, Qt::AspectRatioMode mode) const noexcept;
+    [[nodiscard]] QSizeF scaled(qreal w, qreal h, Qt::AspectRatioMode mode) const noexcept;
+    [[nodiscard]] QSizeF scaled(const QSizeF &s, Qt::AspectRatioMode mode) const noexcept;
 
-    Q_REQUIRED_RESULT constexpr inline QSizeF expandedTo(const QSizeF &) const noexcept;
-    Q_REQUIRED_RESULT constexpr inline QSizeF boundedTo(const QSizeF &) const noexcept;
+    [[nodiscard]] constexpr inline QSizeF expandedTo(const QSizeF &) const noexcept;
+    [[nodiscard]] constexpr inline QSizeF boundedTo(const QSizeF &) const noexcept;
 
-    Q_REQUIRED_RESULT constexpr QSizeF grownBy(QMarginsF m) const noexcept
+    [[nodiscard]] constexpr QSizeF grownBy(QMarginsF m) const noexcept
     { return {width() + m.left() + m.right(), height() + m.top() + m.bottom()}; }
-    Q_REQUIRED_RESULT constexpr QSizeF shrunkBy(QMarginsF m) const noexcept
+    [[nodiscard]] constexpr QSizeF shrunkBy(QMarginsF m) const noexcept
     { return {width() - m.left() - m.right(), height() - m.top() - m.bottom()}; }
 
     constexpr inline qreal &rwidth() noexcept;
@@ -273,8 +273,8 @@ public:
     constexpr inline QSize toSize() const noexcept;
 
 #if defined(Q_OS_DARWIN) || defined(Q_QDOC)
-    Q_REQUIRED_RESULT static QSizeF fromCGSize(CGSize size) noexcept;
-    Q_REQUIRED_RESULT CGSize toCGSize() const noexcept;
+    [[nodiscard]] static QSizeF fromCGSize(CGSize size) noexcept;
+    [[nodiscard]] CGSize toCGSize() const noexcept;
 #endif
 
 private:
diff --git a/src/corelib/tools/qversionnumber.h b/src/corelib/tools/qversionnumber.h
index 4704db2c10..51d61004f6 100644
--- a/src/corelib/tools/qversionnumber.h
+++ b/src/corelib/tools/qversionnumber.h
@@ -237,43 +237,43 @@ public:
     inline explicit QVersionNumber(int maj, int min, int mic)
     { m_segments.setSegments(3, maj, min, mic); }
 
-    Q_REQUIRED_RESULT inline bool isNull() const noexcept
+    [[nodiscard]] inline bool isNull() const noexcept
     { return segmentCount() == 0; }
 
-    Q_REQUIRED_RESULT inline bool isNormalized() const noexcept
+    [[nodiscard]] inline bool isNormalized() const noexcept
     { return isNull() || segmentAt(segmentCount() - 1) != 0; }
 
-    Q_REQUIRED_RESULT inline int majorVersion() const noexcept
+    [[nodiscard]] inline int majorVersion() const noexcept
     { return segmentAt(0); }
 
-    Q_REQUIRED_RESULT inline int minorVersion() const noexcept
+    [[nodiscard]] inline int minorVersion() const noexcept
     { return segmentAt(1); }
 
-    Q_REQUIRED_RESULT inline int microVersion() const noexcept
+    [[nodiscard]] inline int microVersion() const noexcept
     { return segmentAt(2); }
 
-    Q_REQUIRED_RESULT Q_CORE_EXPORT QVersionNumber normalized() const;
+    [[nodiscard]] Q_CORE_EXPORT QVersionNumber normalized() const;
 
-    Q_REQUIRED_RESULT Q_CORE_EXPORT QList<int> segments() const;
+    [[nodiscard]] Q_CORE_EXPORT QList<int> segments() const;
 
-    Q_REQUIRED_RESULT inline int segmentAt(int index) const noexcept
+    [[nodiscard]] inline int segmentAt(int index) const noexcept
     { return (m_segments.size() > index) ? m_segments.at(index) : 0; }
 
-    Q_REQUIRED_RESULT inline int segmentCount() const noexcept
+    [[nodiscard]] inline int segmentCount() const noexcept
     { return m_segments.size(); }
 
-    Q_REQUIRED_RESULT Q_CORE_EXPORT bool isPrefixOf(const QVersionNumber &other) const noexcept;
+    [[nodiscard]] Q_CORE_EXPORT bool isPrefixOf(const QVersionNumber &other) const noexcept;
 
-    Q_REQUIRED_RESULT Q_CORE_EXPORT static int compare(const QVersionNumber &v1, const QVersionNumber &v2) noexcept;
+    [[nodiscard]] Q_CORE_EXPORT static int compare(const QVersionNumber &v1, const QVersionNumber &v2) noexcept;
 
-    Q_REQUIRED_RESULT Q_CORE_EXPORT static Q_DECL_PURE_FUNCTION QVersionNumber commonPrefix(const QVersionNumber &v1, const QVersionNumber &v2);
+    [[nodiscard]] Q_CORE_EXPORT static Q_DECL_PURE_FUNCTION QVersionNumber commonPrefix(const QVersionNumber &v1, const QVersionNumber &v2);
 
-    Q_REQUIRED_RESULT Q_CORE_EXPORT QString toString() const;
+    [[nodiscard]] Q_CORE_EXPORT QString toString() const;
 #if QT_STRINGVIEW_LEVEL < 2
-    Q_REQUIRED_RESULT Q_CORE_EXPORT static Q_DECL_PURE_FUNCTION QVersionNumber fromString(const QString &string, int *suffixIndex = nullptr);
+    [[nodiscard]] Q_CORE_EXPORT static Q_DECL_PURE_FUNCTION QVersionNumber fromString(const QString &string, int *suffixIndex = nullptr);
 #endif
-    Q_REQUIRED_RESULT Q_CORE_EXPORT static Q_DECL_PURE_FUNCTION QVersionNumber fromString(QLatin1String string, int *suffixIndex = nullptr);
-    Q_REQUIRED_RESULT Q_CORE_EXPORT static Q_DECL_PURE_FUNCTION QVersionNumber fromString(QStringView string, int *suffixIndex = nullptr);
+    [[nodiscard]] Q_CORE_EXPORT static Q_DECL_PURE_FUNCTION QVersionNumber fromString(QLatin1String string, int *suffixIndex = nullptr);
+    [[nodiscard]] Q_CORE_EXPORT static Q_DECL_PURE_FUNCTION QVersionNumber fromString(QStringView string, int *suffixIndex = nullptr);
 
 private:
 #ifndef QT_NO_DATASTREAM
@@ -288,22 +288,22 @@ Q_DECLARE_TYPEINFO(QVersionNumber, Q_MOVABLE_TYPE);
 Q_CORE_EXPORT QDebug operator<<(QDebug, const QVersionNumber &version);
 #endif
 
-Q_REQUIRED_RESULT inline bool operator> (const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
+[[nodiscard]] inline bool operator> (const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
 { return QVersionNumber::compare(lhs, rhs) > 0; }
 
-Q_REQUIRED_RESULT inline bool operator>=(const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
+[[nodiscard]] inline bool operator>=(const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
 { return QVersionNumber::compare(lhs, rhs) >= 0; }
 
-Q_REQUIRED_RESULT inline bool operator< (const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
+[[nodiscard]] inline bool operator< (const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
 { return QVersionNumber::compare(lhs, rhs) < 0; }
 
-Q_REQUIRED_RESULT inline bool operator<=(const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
+[[nodiscard]] inline bool operator<=(const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
 { return QVersionNumber::compare(lhs, rhs) <= 0; }
 
-Q_REQUIRED_RESULT inline bool operator==(const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
+[[nodiscard]] inline bool operator==(const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
 { return QVersionNumber::compare(lhs, rhs) == 0; }
 
-Q_REQUIRED_RESULT inline bool operator!=(const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
+[[nodiscard]] inline bool operator!=(const QVersionNumber &lhs, const QVersionNumber &rhs) noexcept
 { return QVersionNumber::compare(lhs, rhs) != 0; }
 
 class QTypeRevision;