diff --git a/src/corelib/tools/qhash.cpp b/src/corelib/tools/qhash.cpp
index 6d7ed95aca..bc8c9490d9 100644
--- a/src/corelib/tools/qhash.cpp
+++ b/src/corelib/tools/qhash.cpp
@@ -1865,14 +1865,15 @@ size_t qHash(long double key, size_t seed) noexcept
     \sa count(), QMultiHash::contains()
 */
 
-/*! \fn template <class Key, class T> T QHash<Key, T>::value(const Key &key, const T &defaultValue = T()) const
+/*! \fn template <class Key, class T> T QHash<Key, T>::value(const Key &key) const
+    \fn template <class Key, class T> T QHash<Key, T>::value(const Key &key, const T &defaultValue) const
     \overload
 
     Returns the value associated with the \a key.
 
     If the hash contains no item with the \a key, the function
-    returns \a defaultValue, which is a \l{default-constructed value} if the
-    parameter has not been specified.
+    returns \a defaultValue, or a \l{default-constructed value} if this
+    parameter has not been supplied.
 */
 
 /*! \fn template <class Key, class T> T &QHash<Key, T>::operator[](const Key &key)
@@ -1935,11 +1936,13 @@ size_t qHash(long double key, size_t seed) noexcept
 */
 
 /*!
-    \fn template <class Key, class T> Key QHash<Key, T>::key(const T &value, const Key &defaultKey = Key()) const
+    \fn template <class Key, class T> Key QHash<Key, T>::key(const T &value) const
+    \fn template <class Key, class T> Key QHash<Key, T>::key(const T &value, const Key &defaultKey) const
     \since 4.3
 
-    Returns the first key mapped to \a value, or \a defaultKey if the
-    hash contains no item mapped to \a value.
+    Returns the first key mapped to \a value. If the hash contains no item
+    mapped to \a value, returns \a defaultKey, or a \l{default-constructed
+    value}{default-constructed key} if this parameter has not been supplied.
 
     This function can be slow (\l{linear time}), because QHash's
     internal data structure is optimized for fast lookup by key, not
@@ -2899,14 +2902,14 @@ size_t qHash(long double key, size_t seed) noexcept
     \sa keys(), values()
 */
 
-/*! \fn template <class Key, class T> T QMultiHash<Key, T>::value(const Key &key, const T &defaultValue = T()) const
-    \overload
+/*! \fn template <class Key, class T> T QMultiHash<Key, T>::value(const Key &key) const
+    \fn template <class Key, class T> T QMultiHash<Key, T>::value(const Key &key, const T &defaultValue) const
 
     Returns the value associated with the \a key.
 
     If the hash contains no item with the \a key, the function
-    returns \a defaultValue, which is a \l{default-constructed value} if the
-    parameter has not been specified.
+    returns \a defaultValue, or a \l{default-constructed value} if this
+    parameter has not been supplied.
 
     If there are multiple
     items for the \a key in the hash, the value of the most recently
@@ -3054,11 +3057,13 @@ size_t qHash(long double key, size_t seed) noexcept
 */
 
 /*!
-    \fn template <class Key, class T> Key QMultiHash<Key, T>::key(const T &value, const Key &defaultKey = Key()) const
+    \fn template <class Key, class T> Key QMultiHash<Key, T>::key(const T &value) const
+    \fn template <class Key, class T> Key QMultiHash<Key, T>::key(const T &value, const Key &defaultKey) const
     \since 4.3
 
-    Returns the first key mapped to \a value, or \a defaultKey if the
-    hash contains no item mapped to \a value.
+    Returns the first key mapped to \a value. If the hash contains no item
+    mapped to \a value, returns \a defaultKey, or a \l{default-constructed
+    value}{default-constructed key} if this parameter has not been supplied.
 
     This function can be slow (\l{linear time}), because QMultiHash's
     internal data structure is optimized for fast lookup by key, not
diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 3d92d95e62..0d5fa52111 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -926,28 +926,64 @@ public:
         return contains(key) ? 1 : 0;
     }
 
-    Key key(const T &value, const Key &defaultKey = Key()) const noexcept
+private:
+    const Key *keyImpl(const T &value) const noexcept
     {
         if (d) {
             const_iterator i = begin();
             while (i != end()) {
                 if (i.value() == value)
-                    return i.key();
+                    return &i.key();
                 ++i;
             }
         }
 
-        return defaultKey;
+        return nullptr;
     }
-    T value(const Key &key, const T &defaultValue = T()) const noexcept
+
+public:
+    Key key(const T &value) const noexcept
+    {
+        if (auto *k = keyImpl(value))
+            return *k;
+        else
+            return Key();
+    }
+    Key key(const T &value, const Key &defaultKey) const noexcept
+    {
+        if (auto *k = keyImpl(value))
+            return *k;
+        else
+            return defaultKey;
+    }
+
+private:
+    T *valueImpl(const Key &key) const noexcept
     {
         if (d) {
             Node *n = d->findNode(key);
             if (n)
-                return n->value;
+                return &n->value;
         }
-        return defaultValue;
+        return nullptr;
     }
+public:
+    T value(const Key &key) const noexcept
+    {
+        if (T *v = valueImpl(key))
+            return *v;
+        else
+            return T();
+    }
+
+    T value(const Key &key, const T &defaultValue) const noexcept
+    {
+        if (T *v = valueImpl(key))
+            return *v;
+        else
+            return defaultValue;
+    }
+
     T &operator[](const Key &key)
     {
         detach();
@@ -1427,30 +1463,63 @@ public:
         return d->findNode(key) != nullptr;
     }
 
-    Key key(const T &value, const Key &defaultKey = Key()) const noexcept
+private:
+    const Key *keyImpl(const T &value) const noexcept
     {
         if (d) {
             auto i = d->begin();
             while (i != d->end()) {
                 Chain *e = i.node()->value;
                 if (e->contains(value))
-                    return i.node()->key;
+                    return &i.node()->key;
                 ++i;
             }
         }
 
-        return defaultKey;
+        return nullptr;
     }
-    T value(const Key &key, const T &defaultValue = T()) const noexcept
+public:
+    Key key(const T &value) const noexcept
+    {
+        if (auto *k = keyImpl(value))
+            return *k;
+        else
+            return Key();
+    }
+    Key key(const T &value, const Key &defaultKey) const noexcept
+    {
+        if (auto *k = keyImpl(value))
+            return *k;
+        else
+            return defaultKey;
+    }
+
+private:
+    T *valueImpl(const Key &key) const noexcept
     {
         if (d) {
             Node *n = d->findNode(key);
             if (n) {
                 Q_ASSERT(n->value);
-                return n->value->value;
+                return &n->value->value;
             }
         }
-        return defaultValue;
+        return nullptr;
+    }
+public:
+    T value(const Key &key) const noexcept
+    {
+        if (auto *v = valueImpl(key))
+            return *v;
+        else
+            return T();
+    }
+    T value(const Key &key, const T &defaultValue) const noexcept
+    {
+        if (auto *v = valueImpl(key))
+            return *v;
+        else
+            return defaultValue;
     }
 
     T &operator[](const Key &key)