diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index ceae0583ee..4817acb48f 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -422,8 +422,8 @@ typedef double qreal;
    operator to disable copying (the compiler gives an error message).
 */
 #define Q_DISABLE_COPY(Class) \
-    Class(const Class &) Q_DECL_EQ_DELETE;\
-    Class &operator=(const Class &) Q_DECL_EQ_DELETE;
+    Class(const Class &) = delete;\
+    Class &operator=(const Class &) = delete;
 
 #define Q_DISABLE_MOVE(Class) \
     Class(Class &&) = delete; \
@@ -1021,7 +1021,7 @@ template <typename T>
 Q_DECL_CONSTEXPR typename std::add_const<T>::type &qAsConst(T &t) noexcept { return t; }
 // prevent rvalue arguments:
 template <typename T>
-void qAsConst(const T &&) Q_DECL_EQ_DELETE;
+void qAsConst(const T &&) = delete;
 
 #ifndef QT_NO_FOREACH
 
diff --git a/src/corelib/kernel/qmetaobject.h b/src/corelib/kernel/qmetaobject.h
index 6c5f78d208..10b14a7e03 100644
--- a/src/corelib/kernel/qmetaobject.h
+++ b/src/corelib/kernel/qmetaobject.h
@@ -183,7 +183,7 @@ private:
     // signature() has been renamed to methodSignature() in Qt 5.
     // Warning, that function returns a QByteArray; check the life time if
     // you convert to char*.
-    char *signature(struct renamedInQt5_warning_checkTheLifeTime * = nullptr) Q_DECL_EQ_DELETE;
+    char *signature(struct renamedInQt5_warning_checkTheLifeTime * = nullptr) = delete;
 #endif
     static QMetaMethod fromSignalImpl(const QMetaObject *, void **);
 
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index a47fbfe28d..79ee5eec11 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -849,7 +849,7 @@ struct VariantData
     const uint flags;
 private:
     // copy constructor allowed to be implicit to silence level 4 warning from MSVC
-    VariantData &operator=(const VariantData &) Q_DECL_EQ_DELETE;
+    VariantData &operator=(const VariantData &) = delete;
 };
 
 template<typename const_iterator>
diff --git a/src/corelib/kernel/qvariant.h b/src/corelib/kernel/qvariant.h
index 2247c7adc8..924cfa1e1a 100644
--- a/src/corelib/kernel/qvariant.h
+++ b/src/corelib/kernel/qvariant.h
@@ -483,27 +483,27 @@ public:
 
 private:
     // force compile error, prevent QVariant(bool) to be called
-    inline QVariant(void *) Q_DECL_EQ_DELETE;
+    inline QVariant(void *) = delete;
     // QVariant::Type is marked as \obsolete, but we don't want to
     // provide a constructor from its intended replacement,
     // QMetaType::Type, instead, because the idea behind these
     // constructors is flawed in the first place. But we also don't
     // want QVariant(QMetaType::String) to compile and falsely be an
     // int variant, so delete this constructor:
-    QVariant(QMetaType::Type) Q_DECL_EQ_DELETE;
+    QVariant(QMetaType::Type) = delete;
 
     // These constructors don't create QVariants of the type associcated
     // with the enum, as expected, but they would create a QVariant of
     // type int with the value of the enum value.
     // Use QVariant v = QColor(Qt::red) instead of QVariant v = Qt::red for
     // example.
-    QVariant(Qt::GlobalColor) Q_DECL_EQ_DELETE;
-    QVariant(Qt::BrushStyle) Q_DECL_EQ_DELETE;
-    QVariant(Qt::PenStyle) Q_DECL_EQ_DELETE;
-    QVariant(Qt::CursorShape) Q_DECL_EQ_DELETE;
+    QVariant(Qt::GlobalColor) = delete;
+    QVariant(Qt::BrushStyle) = delete;
+    QVariant(Qt::PenStyle) = delete;
+    QVariant(Qt::CursorShape) = delete;
 #ifdef QT_NO_CAST_FROM_ASCII
     // force compile error when implicit conversion is not wanted
-    inline QVariant(const char *) Q_DECL_EQ_DELETE;
+    inline QVariant(const char *) = delete;
 #endif
 public:
     typedef Private DataPtr;
diff --git a/src/corelib/thread/qatomic_cxx11.h b/src/corelib/thread/qatomic_cxx11.h
index 32d27734fc..2851bae73e 100644
--- a/src/corelib/thread/qatomic_cxx11.h
+++ b/src/corelib/thread/qatomic_cxx11.h
@@ -462,7 +462,7 @@ template <typename X> struct QAtomicOps
     }
 };
 
-#if defined(Q_COMPILER_CONSTEXPR) && defined(Q_COMPILER_DEFAULT_MEMBERS) && defined(Q_COMPILER_DELETE_MEMBERS)
+#if defined(Q_COMPILER_CONSTEXPR)
 #  define Q_BASIC_ATOMIC_INITIALIZER(a)     { a }
 #else
 #  define Q_BASIC_ATOMIC_INITIALIZER(a)     { ATOMIC_VAR_INIT(a) }
diff --git a/src/corelib/thread/qbasicatomic.h b/src/corelib/thread/qbasicatomic.h
index 4c3c1fc01f..7d2e06a499 100644
--- a/src/corelib/thread/qbasicatomic.h
+++ b/src/corelib/thread/qbasicatomic.h
@@ -75,7 +75,7 @@ QT_END_NAMESPACE
 
 // New atomics
 
-#if defined(Q_COMPILER_CONSTEXPR) && defined(Q_COMPILER_DEFAULT_MEMBERS) && defined(Q_COMPILER_DELETE_MEMBERS)
+#if defined(Q_COMPILER_CONSTEXPR)
 # if defined(Q_CC_CLANG) && Q_CC_CLANG < 303
    /*
       Do not define QT_BASIC_ATOMIC_HAS_CONSTRUCTORS for Clang before version 3.3.
diff --git a/src/corelib/thread/qthread.h b/src/corelib/thread/qthread.h
index 8e92d75401..c7a6dc8f1a 100644
--- a/src/corelib/thread/qthread.h
+++ b/src/corelib/thread/qthread.h
@@ -209,7 +209,6 @@ struct Callable
     {
     }
 
-#if defined(Q_COMPILER_DEFAULT_MEMBERS) && defined(Q_COMPILER_DELETE_MEMBERS)
     // Apply the same semantics of a lambda closure type w.r.t. the special
     // member functions, if possible: delete the copy assignment operator,
     // bring back all the others as per the RO5 (cf. §8.1.5.1/11 [expr.prim.lambda.closure])
@@ -218,7 +217,6 @@ struct Callable
     Callable(Callable &&) = default;
     Callable &operator=(const Callable &) = delete;
     Callable &operator=(Callable &&) = default;
-#endif
 
     void operator()()
     {
diff --git a/src/corelib/tools/qmap.h b/src/corelib/tools/qmap.h
index 3b8aad9a33..2d01a75a42 100644
--- a/src/corelib/tools/qmap.h
+++ b/src/corelib/tools/qmap.h
@@ -142,7 +142,7 @@ private:
             rightNode()->destroySubTree();
     }
 
-    QMapNode() Q_DECL_EQ_DELETE;
+    QMapNode() = delete;
     Q_DISABLE_COPY(QMapNode)
 };
 
diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h
index 9fb452da6b..c219d310dc 100644
--- a/src/corelib/tools/qsharedpointer_impl.h
+++ b/src/corelib/tools/qsharedpointer_impl.h
@@ -235,8 +235,8 @@ namespace QtSharedPointer {
         }
     private:
         // prevent construction
-        ExternalRefCountWithCustomDeleter() Q_DECL_EQ_DELETE;
-        ~ExternalRefCountWithCustomDeleter() Q_DECL_EQ_DELETE;
+        ExternalRefCountWithCustomDeleter() = delete;
+        ~ExternalRefCountWithCustomDeleter() = delete;
         Q_DISABLE_COPY(ExternalRefCountWithCustomDeleter)
     };
 
@@ -280,8 +280,8 @@ namespace QtSharedPointer {
 
     private:
         // prevent construction
-        ExternalRefCountWithContiguousData() Q_DECL_EQ_DELETE;
-        ~ExternalRefCountWithContiguousData() Q_DECL_EQ_DELETE;
+        ExternalRefCountWithContiguousData() = delete;
+        ~ExternalRefCountWithContiguousData() = delete;
         Q_DISABLE_COPY(ExternalRefCountWithContiguousData)
     };
 
@@ -705,11 +705,7 @@ template <class T>
 class QEnableSharedFromThis
 {
 protected:
-#ifdef Q_COMPILER_DEFAULT_MEMBERS
     QEnableSharedFromThis() = default;
-#else
-    Q_DECL_CONSTEXPR QEnableSharedFromThis() {}
-#endif
     QEnableSharedFromThis(const QEnableSharedFromThis &) {}
     QEnableSharedFromThis &operator=(const QEnableSharedFromThis &) { return *this; }
 
diff --git a/src/corelib/tools/qstringbuilder.h b/src/corelib/tools/qstringbuilder.h
index 79ed10c7a8..b3cf2f695e 100644
--- a/src/corelib/tools/qstringbuilder.h
+++ b/src/corelib/tools/qstringbuilder.h
@@ -150,7 +150,7 @@ class QStringBuilder <QString, QString> : public QStringBuilderBase<QStringBuild
         const QString &b;
 
     private:
-        QStringBuilder &operator=(const QStringBuilder &) Q_DECL_EQ_DELETE;
+        QStringBuilder &operator=(const QStringBuilder &) = delete;
 };
 
 template <>
@@ -167,7 +167,7 @@ class QStringBuilder <QByteArray, QByteArray> : public QStringBuilderBase<QStrin
         const QByteArray &b;
 
     private:
-        QStringBuilder &operator=(const QStringBuilder &) Q_DECL_EQ_DELETE;
+        QStringBuilder &operator=(const QStringBuilder &) = delete;
 };
 
 
diff --git a/src/gui/image/qiconengine.h b/src/gui/image/qiconengine.h
index 0c5b51dc71..89fed5ccda 100644
--- a/src/gui/image/qiconengine.h
+++ b/src/gui/image/qiconengine.h
@@ -94,7 +94,7 @@ public:
     virtual void virtual_hook(int id, void *data);
 
 private:
-    QIconEngine &operator=(const QIconEngine &other) Q_DECL_EQ_DELETE;
+    QIconEngine &operator=(const QIconEngine &other) = delete;
 };
 
 #if QT_DEPRECATED_SINCE(5, 0)
diff --git a/src/widgets/kernel/qtooltip.h b/src/widgets/kernel/qtooltip.h
index edf1de0c1d..1b263a6629 100644
--- a/src/widgets/kernel/qtooltip.h
+++ b/src/widgets/kernel/qtooltip.h
@@ -50,7 +50,7 @@ QT_BEGIN_NAMESPACE
 
 class Q_WIDGETS_EXPORT QToolTip
 {
-    QToolTip() Q_DECL_EQ_DELETE;
+    QToolTip() = delete;
 public:
     // ### Qt 6 - merge the three showText functions below
     static void showText(const QPoint &pos, const QString &text, QWidget *w = nullptr);
diff --git a/src/widgets/kernel/qwhatsthis.h b/src/widgets/kernel/qwhatsthis.h
index 59c0b01c9b..fa5b97d98a 100644
--- a/src/widgets/kernel/qwhatsthis.h
+++ b/src/widgets/kernel/qwhatsthis.h
@@ -54,7 +54,7 @@ class QAction;
 
 class Q_WIDGETS_EXPORT QWhatsThis
 {
-    QWhatsThis() Q_DECL_EQ_DELETE;
+    QWhatsThis() = delete;
 
 public:
     static void enterWhatsThisMode();
diff --git a/src/xml/sax/qxml.h b/src/xml/sax/qxml.h
index 26b674c894..9be14bd7a9 100644
--- a/src/xml/sax/qxml.h
+++ b/src/xml/sax/qxml.h
@@ -116,12 +116,10 @@ class Q_XML_EXPORT QXmlAttributes
 {
 public:
     QXmlAttributes();
-#ifdef Q_COMPILER_DEFAULT_MEMBERS
     QXmlAttributes(const QXmlAttributes &) = default;
     QXmlAttributes(QXmlAttributes &&) noexcept = default;
     QXmlAttributes &operator=(const QXmlAttributes &) = default;
     QXmlAttributes &operator=(QXmlAttributes &&) noexcept = default;
-#endif // default members
 
     QT6_NOT_VIRTUAL ~QXmlAttributes();