diff --git a/src/widgets/kernel/qsizepolicy.cpp b/src/widgets/kernel/qsizepolicy.cpp
index c354d14f5e1..fe34ef5982b 100644
--- a/src/widgets/kernel/qsizepolicy.cpp
+++ b/src/widgets/kernel/qsizepolicy.cpp
@@ -317,9 +317,8 @@ void QSizePolicy::setControlType(ControlType type) noexcept
 */
 
 /*!
-    \fn size_t qHash(QSizePolicy key, size_t seed = 0)
+    \fn size_t QSizePolicy::qHash(QSizePolicy key, size_t seed = 0)
     \since 5.6
-    \relates QSizePolicy
 
     Returns the hash value for \a key, using
     \a seed to seed the calculation.
diff --git a/src/widgets/kernel/qsizepolicy.h b/src/widgets/kernel/qsizepolicy.h
index 5e948175f31..53c7afc9069 100644
--- a/src/widgets/kernel/qsizepolicy.h
+++ b/src/widgets/kernel/qsizepolicy.h
@@ -43,14 +43,13 @@
 #include <QtWidgets/qtwidgetsglobal.h>
 #include <QtCore/qobject.h>
 #include <QtCore/qalgorithms.h>
+#include <QtCore/qhashfunctions.h>
 
 QT_BEGIN_NAMESPACE
 
 class QVariant;
 class QSizePolicy;
 
-Q_DECL_CONST_FUNCTION inline size_t qHash(QSizePolicy key, size_t seed = 0) noexcept;
-
 class Q_WIDGETS_EXPORT QSizePolicy
 {
     Q_GADGET
@@ -122,7 +121,7 @@ public:
     constexpr bool operator==(const QSizePolicy& s) const noexcept { return data == s.data; }
     constexpr bool operator!=(const QSizePolicy& s) const noexcept { return data != s.data; }
 
-    friend Q_DECL_CONST_FUNCTION size_t qHash(QSizePolicy key, size_t seed) noexcept { return qHash(key.data, seed); }
+    friend Q_DECL_CONST_FUNCTION size_t qHash(QSizePolicy key, size_t seed = 0) noexcept { return qHash(key.data, seed); }
 
     operator QVariant() const;