diff --git a/src/corelib/mimetypes/qmimeglobpattern.cpp b/src/corelib/mimetypes/qmimeglobpattern.cpp
index 049a947939..b11add87e4 100644
--- a/src/corelib/mimetypes/qmimeglobpattern.cpp
+++ b/src/corelib/mimetypes/qmimeglobpattern.cpp
@@ -165,15 +165,15 @@ void QMimeAllGlobPatterns::addGlob(const QMimeGlobPattern &glob)
         // The bulk of the patterns is *.foo with weight 50 --> those go into the fast patterns hash.
         const QString extension = pattern.mid(2).toLower();
         QStringList &patterns = m_fastPatterns[extension]; // find or create
-        // This would just slow things down: if (!patterns.contains(glob.mimeType()))
-        patterns.append(glob.mimeType());
+        if (!patterns.contains(glob.mimeType()))
+            patterns.append(glob.mimeType());
     } else {
         if (glob.weight() > 50) {
-            // This would just slow things down: if (!m_highWeightGlobs.hasPattern(glob.mimeType(), glob.pattern()))
-            m_highWeightGlobs.append(glob);
+            if (!m_highWeightGlobs.hasPattern(glob.mimeType(), glob.pattern()))
+                m_highWeightGlobs.append(glob);
         } else {
-            //This would just slow things down: if (!m_lowWeightGlobs.hasPattern(glob.mimeType(), glob.pattern()))
-            m_lowWeightGlobs.append(glob);
+            if (!m_lowWeightGlobs.hasPattern(glob.mimeType(), glob.pattern()))
+                m_lowWeightGlobs.append(glob);
         }
     }
 }
diff --git a/tests/auto/corelib/mimetypes/qmimedatabase/qml-again.xml b/tests/auto/corelib/mimetypes/qmimedatabase/qml-again.xml
new file mode 100644
index 0000000000..d2461e02f9
--- /dev/null
+++ b/tests/auto/corelib/mimetypes/qmimedatabase/qml-again.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0"?>
+<mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'>
+  <mime-type type="text/x-qml">
+    <comment>Qt Markup Language file</comment>
+    <magic priority="80">
+      <match type="string" value="import Qt " offset="0:256"/>
+    </magic>
+    <glob pattern="*.qml"/>
+  </mime-type>
+</mime-info>
+
+
diff --git a/tests/auto/corelib/mimetypes/qmimedatabase/test.qml b/tests/auto/corelib/mimetypes/qmimedatabase/test.qml
new file mode 100644
index 0000000000..5603b599d1
--- /dev/null
+++ b/tests/auto/corelib/mimetypes/qmimedatabase/test.qml
@@ -0,0 +1,44 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 David Faure <faure@kde.org>
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 1.1
+Item {
+}
diff --git a/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp b/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp
index 0d41328320..740a9ea388 100644
--- a/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp
+++ b/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp
@@ -52,6 +52,7 @@
 #include <QtTest/QtTest>
 
 static const char yastFileName[] ="yast2-metapackage-handler-mimetypes.xml";
+static const char qmlAgainFileName[] ="qml-again.xml";
 
 void initializeLang()
 {
@@ -121,6 +122,10 @@ void tst_QMimeDatabase::initTestCase()
     QVERIFY2(!m_yastMimeTypes.isEmpty(),
              qPrintable(QString::fromLatin1("Cannot find '%1' starting from '%2'").
                         arg(yastFileName, QDir::currentPath())));
+    m_qmlAgainFileName = QFINDTESTDATA(qmlAgainFileName);
+    QVERIFY2(!m_qmlAgainFileName.isEmpty(),
+             qPrintable(QString::fromLatin1("Cannot find '%1' starting from '%2'").
+                        arg(qmlAgainFileName, QDir::currentPath())));
 
     init();
 }
@@ -796,11 +801,14 @@ void tst_QMimeDatabase::installNewGlobalMimeType()
     const QString destDir = mimeDir + QLatin1String("/packages/");
     const QString destFile = destDir + QLatin1String(yastFileName);
     QFile::remove(destFile);
+    const QString destQmlFile = destDir + QLatin1String(qmlAgainFileName);
+    QFile::remove(destQmlFile);
     //qDebug() << destFile;
 
     if (!QFileInfo(destDir).isDir())
         QVERIFY(QDir(m_globalXdgDir).mkpath(destDir));
     QVERIFY(QFile::copy(m_yastMimeTypes, destFile));
+    QVERIFY(QFile::copy(m_qmlAgainFileName, destQmlFile));
     if (!waitAndRunUpdateMimeDatabase(mimeDir))
         QSKIP("shared-mime-info not found, skipping mime.cache test");
 
@@ -809,8 +817,17 @@ void tst_QMimeDatabase::installNewGlobalMimeType()
     QVERIFY(db.mimeTypeForName(QLatin1String("text/x-suse-ymp")).isValid());
     checkHasMimeType("text/x-suse-ymp");
 
+    // Test that a double-definition of a mimetype doesn't lead to sniffing ("conflicting globs").
+    const QString qmlTestFile = QFINDTESTDATA("test.qml");
+    QVERIFY2(!qmlTestFile.isEmpty(),
+             qPrintable(QString::fromLatin1("Cannot find '%1' starting from '%2'").
+                        arg("test.qml", QDir::currentPath())));
+    QCOMPARE(db.mimeTypeForFile(qmlTestFile).name(),
+             QString::fromLatin1("text/x-qml"));
+
     // Now test removing it again
     QFile::remove(destFile);
+    QFile::remove(destQmlFile);
     if (!waitAndRunUpdateMimeDatabase(mimeDir))
         QSKIP("shared-mime-info not found, skipping mime.cache test");
     QCOMPARE(db.mimeTypeForFile(QLatin1String("foo.ymu"), QMimeDatabase::MatchExtension).name(),
diff --git a/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.h b/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.h
index ea050b5014..6db09e2078 100644
--- a/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.h
+++ b/tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.h
@@ -97,6 +97,7 @@ private:
     QString m_globalXdgDir;
     QString m_localXdgDir;
     QString m_yastMimeTypes;
+    QString m_qmlAgainFileName;
     QTemporaryDir m_temporaryDir;
     QString m_testSuite;
 };