Merge remote-tracking branch 'origin/5.7' into dev

Change-Id: Ic7aaa06f4a14b1aed61faa1a6e7f527ee0eeb96b

3 files changed, 15 insertions, 4 deletions

diff --git a/src/corelib/tools/qregexp.cpp b/src/corelib/tools/qregexp.cpp
index fd67193302..f8f3347786 100644
--- a/src/corelib/tools/qregexp.cpp
+++ b/src/corelib/tools/qregexp.cpp
@@ -2335,7 +2335,7 @@ QRegExpCharClass::QRegExpCharClass()
 void QRegExpCharClass::clear()
 {
     c = 0;
-    r.resize(0);
+    r.clear();
     n = false;
 }
 
diff --git a/src/corelib/tools/qvector.cpp b/src/corelib/tools/qvector.cpp
index b3247b8af5..ef1c9c17b0 100644
--- a/src/corelib/tools/qvector.cpp
+++ b/src/corelib/tools/qvector.cpp
@@ -502,8 +502,19 @@
 
 /*! \fn void QVector::clear()
 
-    Removes all the elements from the vector and releases the memory used by
-    the vector.
+    Removes all the elements from the vector.
+
+    \note Until Qt 5.6, this also released the memory used by
+    the vector. From Qt 5.7, the capacity is preserved. To shed
+    all capacity, swap with a default-constructed vector:
+    \code
+    QVector<T> v ...;
+    QVector<T>().swap(v);
+    Q_ASSERT(v.capacity() == 0);
+    \endcode
+    or call squeeze().
+
+    \sa squeeze()
 */
 
 /*! \fn const T &QVector::at(int i) const
diff --git a/src/corelib/tools/qvector.h b/src/corelib/tools/qvector.h
index d60be78ade..13ae121450 100644
--- a/src/corelib/tools/qvector.h
+++ b/src/corelib/tools/qvector.h
@@ -419,7 +419,7 @@ void QVector<T>::resize(int asize)
 }
 template <typename T>
 inline void QVector<T>::clear()
-{ *this = QVector<T>(); }
+{ resize(0); }
 template <typename T>
 inline const T &QVector<T>::at(int i) const
 { Q_ASSERT_X(i >= 0 && i < d->size, "QVector<T>::at", "index out of range");