Make the QMultiHash(const QHash &) constructor explicit

And add a QMultiHash::unite(const QHash &) method to avoid
a copy of the data when inserting a QHash into a multi hash.

Change-Id: I864aa9d2b9b7b2c367c3c4d140a2ce2f5408ae09
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/tests/auto/corelib/tools/qhash/tst_qhash.cpp b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
index d63ed7043e..3174bd60b8 100644
--- a/tests/auto/corelib/tools/qhash/tst_qhash.cpp
+++ b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
@@ -1320,6 +1320,12 @@ void tst_QHash::qmultihash_specific()
     QVERIFY(map1.remove(42,5));
     QVERIFY(map2.remove(42,5));
     QVERIFY(map1 == map2);
+
+    QHash<int, int> hash;
+    hash.insert(-1, -1);
+    map2.unite(hash);
+    QCOMPARE(map2.count(), 6);
+    QCOMPARE(map2[-1], -1);
     }
 }