diff --git a/src/corelib/global/qflags.h b/src/corelib/global/qflags.h
index 2319a788771..e576128bce5 100644
--- a/src/corelib/global/qflags.h
+++ b/src/corelib/global/qflags.h
@@ -144,6 +144,13 @@ public:
     constexpr inline QFlags operator&(Enum other) const noexcept { return QFlags(QFlag(i & Int(other))); }
     constexpr inline QFlags operator~() const noexcept { return QFlags(QFlag(~i)); }
 
+    constexpr inline void operator+(QFlags other) const noexcept = delete;
+    constexpr inline void operator+(Enum other) const noexcept = delete;
+    constexpr inline void operator+(int other) const noexcept = delete;
+    constexpr inline void operator-(QFlags other) const noexcept = delete;
+    constexpr inline void operator-(Enum other) const noexcept = delete;
+    constexpr inline void operator-(int other) const noexcept = delete;
+
     constexpr inline bool operator!() const noexcept { return !i; }
 
     constexpr inline bool testFlag(Enum flag) const noexcept { return (i & Int(flag)) == Int(flag) && (Int(flag) != 0 || i == Int(flag) ); }
@@ -170,13 +177,24 @@ typedef QFlags<Enum> Flags;
 
 #define Q_DECLARE_INCOMPATIBLE_FLAGS(Flags) \
 constexpr inline QIncompatibleFlag operator|(Flags::enum_type f1, int f2) noexcept \
-{ return QIncompatibleFlag(int(f1) | f2); }
+{ return QIncompatibleFlag(int(f1) | f2); } \
+constexpr inline void operator+(int f1, Flags::enum_type f2) noexcept = delete; \
+constexpr inline void operator+(Flags::enum_type f1, int f2) noexcept = delete; \
+constexpr inline void operator-(int f1, Flags::enum_type f2) noexcept = delete; \
+constexpr inline void operator-(Flags::enum_type f1, int f2) noexcept = delete;
 
 #define Q_DECLARE_OPERATORS_FOR_FLAGS(Flags) \
 constexpr inline QFlags<Flags::enum_type> operator|(Flags::enum_type f1, Flags::enum_type f2) noexcept \
 { return QFlags<Flags::enum_type>(f1) | f2; } \
 constexpr inline QFlags<Flags::enum_type> operator|(Flags::enum_type f1, QFlags<Flags::enum_type> f2) noexcept \
-{ return f2 | f1; } Q_DECLARE_INCOMPATIBLE_FLAGS(Flags)
+{ return f2 | f1; } \
+constexpr inline void operator+(Flags::enum_type f1, Flags::enum_type f2) noexcept = delete; \
+constexpr inline void operator+(Flags::enum_type f1, QFlags<Flags::enum_type> f2) noexcept = delete; \
+constexpr inline void operator+(int f1, QFlags<Flags::enum_type> f2) noexcept = delete; \
+constexpr inline void operator-(Flags::enum_type f1, Flags::enum_type f2) noexcept = delete; \
+constexpr inline void operator-(Flags::enum_type f1, QFlags<Flags::enum_type> f2) noexcept = delete; \
+constexpr inline void operator-(int f1, QFlags<Flags::enum_type> f2) noexcept = delete; \
+Q_DECLARE_INCOMPATIBLE_FLAGS(Flags)
 
 
 #else /* Q_NO_TYPESAFE_FLAGS */
diff --git a/src/widgets/kernel/qwhatsthis.cpp b/src/widgets/kernel/qwhatsthis.cpp
index b483655a710..d264dfc4b2c 100644
--- a/src/widgets/kernel/qwhatsthis.cpp
+++ b/src/widgets/kernel/qwhatsthis.cpp
@@ -218,8 +218,8 @@ QWhatsThat::QWhatsThat(const QString& txt, QWidget* parent, QWidget *showTextFor
             sw = 300;
 
         r = fontMetrics().boundingRect(0, 0, sw, 1000,
-                                        Qt::AlignLeft + Qt::AlignTop
-                                        + Qt::TextWordWrap + Qt::TextExpandTabs,
+                                        Qt::AlignLeft | Qt::AlignTop
+                                        | Qt::TextWordWrap | Qt::TextExpandTabs,
                                         text);
     }
     shadowWidth = dropShadow() ? 0 : 6;
@@ -333,7 +333,7 @@ void QWhatsThat::paintEvent(QPaintEvent*)
     }
     else
     {
-        p.drawText(r, Qt::AlignLeft + Qt::AlignTop + Qt::TextWordWrap + Qt::TextExpandTabs, text);
+        p.drawText(r, Qt::AlignLeft | Qt::AlignTop | Qt::TextWordWrap | Qt::TextExpandTabs, text);
     }
 }