diff --git a/src/plugins/projectexplorer/kitmanager.cpp b/src/plugins/projectexplorer/kitmanager.cpp
index a8e34e57f85..db3a79dd2af 100644
--- a/src/plugins/projectexplorer/kitmanager.cpp
+++ b/src/plugins/projectexplorer/kitmanager.cpp
@@ -442,7 +442,7 @@ void KitManager::deleteKit(Kit *k)
     delete k;
 }
 
-QString KitManager::uniqueKitName(const Kit *k, const QString name, const QList<Kit *> &allKits)
+QString KitManager::uniqueKitName(const Kit *k, const QString &name, const QList<Kit *> &allKits)
 {
     QStringList nameList;
     nameList << QString(); // Disallow empty kit names!
diff --git a/src/plugins/projectexplorer/kitmanager.h b/src/plugins/projectexplorer/kitmanager.h
index 0438d8c1729..4c5f66b78ae 100644
--- a/src/plugins/projectexplorer/kitmanager.h
+++ b/src/plugins/projectexplorer/kitmanager.h
@@ -127,7 +127,7 @@ public:
 
     static void deleteKit(Kit *k);
 
-    static QString uniqueKitName(const Kit *k, const QString name, const QList<Kit *> &allKits);
+    static QString uniqueKitName(const Kit *k, const QString &name, const QList<Kit *> &allKits);
 
     static bool registerKit(ProjectExplorer::Kit *k);
     static void deregisterKit(ProjectExplorer::Kit *k);
diff --git a/src/plugins/projectexplorer/kitmodel.cpp b/src/plugins/projectexplorer/kitmodel.cpp
index 042406be0bf..909458db298 100644
--- a/src/plugins/projectexplorer/kitmodel.cpp
+++ b/src/plugins/projectexplorer/kitmodel.cpp
@@ -352,7 +352,7 @@ Kit *KitModel::markForAddition(Kit *baseKit)
     return k;
 }
 
-QString KitModel::findNameFor(Kit *k, const QString baseName)
+QString KitModel::findNameFor(Kit *k, const QString &baseName)
 {
     QList<Kit *> kits = kitList(m_root);
     return KitManager::uniqueKitName(k, baseName, kits);
diff --git a/src/plugins/projectexplorer/kitmodel.h b/src/plugins/projectexplorer/kitmodel.h
index a1746235f8c..031863b97a8 100644
--- a/src/plugins/projectexplorer/kitmodel.h
+++ b/src/plugins/projectexplorer/kitmodel.h
@@ -86,7 +86,7 @@ public:
     void markForRemoval(Kit *k);
     Kit *markForAddition(Kit *baseKit);
 
-    QString findNameFor(Kit *k, const QString baseName);
+    QString findNameFor(Kit *k, const QString &baseName);
 
 signals:
     void kitStateChanged();
diff --git a/src/plugins/projectexplorer/projectfilewizardextension.cpp b/src/plugins/projectexplorer/projectfilewizardextension.cpp
index 4c9f5407405..124e00eda03 100644
--- a/src/plugins/projectexplorer/projectfilewizardextension.cpp
+++ b/src/plugins/projectexplorer/projectfilewizardextension.cpp
@@ -480,7 +480,7 @@ static inline void getProjectChoicesAndToolTips(QStringList *projectChoicesParam
     *projectActionParam = projectAction;
 }
 
-void ProjectFileWizardExtension::initProjectChoices(const QList<GeneratedFile> generatedFiles, const QVariantMap &extraValues)
+void ProjectFileWizardExtension::initProjectChoices(const QList<GeneratedFile> &generatedFiles, const QVariantMap &extraValues)
 {
     QStringList projectChoices;
     QStringList projectToolTips;
diff --git a/src/plugins/projectexplorer/projectfilewizardextension.h b/src/plugins/projectexplorer/projectfilewizardextension.h
index dfa07bb8c45..daad9cd5ee7 100644
--- a/src/plugins/projectexplorer/projectfilewizardextension.h
+++ b/src/plugins/projectexplorer/projectfilewizardextension.h
@@ -59,7 +59,7 @@ public slots:
     void initializeVersionControlChoices();
 
 private:
-    void initProjectChoices(const QList<Core::GeneratedFile> generatedFiles, const QVariantMap &extraValues);
+    void initProjectChoices(const QList<Core::GeneratedFile> &generatedFiles, const QVariantMap &extraValues);
     bool processProject(const QList<Core::GeneratedFile> &files,
                         bool *removeOpenProjectAttribute, QString *errorMessage);
     bool processVersionControl(const QList<Core::GeneratedFile> &files, QString *errorMessage);
diff --git a/src/plugins/projectexplorer/taskmodel.cpp b/src/plugins/projectexplorer/taskmodel.cpp
index 75fb54eb345..7d5ed714fa7 100644
--- a/src/plugins/projectexplorer/taskmodel.cpp
+++ b/src/plugins/projectexplorer/taskmodel.cpp
@@ -438,7 +438,7 @@ void TaskFilterModel::handleRowsAboutToBeRemoved(const QModelIndex &index, int f
     endRemoveRows();
 }
 
-void TaskFilterModel::handleDataChanged(QModelIndex top, QModelIndex bottom)
+void TaskFilterModel::handleDataChanged(const QModelIndex &top, const QModelIndex &bottom)
 {
     const QPair<int, int> range = findFilteredRange(top.row(), bottom.row(), m_mapping);
     if (range.first > range.second)
diff --git a/src/plugins/projectexplorer/taskmodel.h b/src/plugins/projectexplorer/taskmodel.h
index 1032d6be43c..e352d04fccf 100644
--- a/src/plugins/projectexplorer/taskmodel.h
+++ b/src/plugins/projectexplorer/taskmodel.h
@@ -164,7 +164,7 @@ public:
 private slots:
     void handleNewRows(const QModelIndex &index, int first, int last);
     void handleRowsAboutToBeRemoved(const QModelIndex &index, int first, int last);
-    void handleDataChanged(QModelIndex,QModelIndex bottom);
+    void handleDataChanged(const QModelIndex &top, const QModelIndex &bottom);
     void handleReset();
 
 private: