diff --git a/src/TocBuilder.cpp b/src/TocBuilder.cpp
index 1cfeddc450..fb688bd58e 100644
--- a/src/TocBuilder.cpp
+++ b/src/TocBuilder.cpp
@@ -24,7 +24,7 @@ namespace lyx {
 
 
 
-TocBuilder::TocBuilder(shared_ptr<Toc> toc)
+TocBuilder::TocBuilder(shared_ptr<Toc> const & toc)
 	: toc_(toc ? toc : make_shared<Toc>()),
 	  stack_()
 {
diff --git a/src/TocBuilder.h b/src/TocBuilder.h
index 5c3407918a..eca655ca16 100644
--- a/src/TocBuilder.h
+++ b/src/TocBuilder.h
@@ -27,7 +27,7 @@ class DocIterator;
 class TocBuilder
 {
 public:
-	TocBuilder(std::shared_ptr<Toc> toc);
+	TocBuilder(std::shared_ptr<Toc> const & toc);
 	/// Open a level.
 	/// When entering a float or flex or paragraph (with AddToToc)
 	void pushItem(DocIterator const & dit, docstring const & s,
diff --git a/src/frontends/qt/Action.cpp b/src/frontends/qt/Action.cpp
index 818aca0f07..3d3eafa240 100644
--- a/src/frontends/qt/Action.cpp
+++ b/src/frontends/qt/Action.cpp
@@ -40,7 +40,7 @@ Action::Action(FuncRequest func, QIcon const & icon, QString const & text,
 }
 
 
-Action::Action(shared_ptr<FuncRequest const> func,
+Action::Action(shared_ptr<FuncRequest const> const & func,
                QIcon const & icon, QString const & text,
                QString const & tooltip, QObject * parent)
 	: QAction(parent), func_(func), icon_(icon)
diff --git a/src/frontends/qt/Action.h b/src/frontends/qt/Action.h
index 411eb72388..53398a0ec6 100644
--- a/src/frontends/qt/Action.h
+++ b/src/frontends/qt/Action.h
@@ -39,7 +39,7 @@ public:
 
 	// Takes shared ownership of func.
 	// Use for perf-sensitive code such as populating menus.
-	Action(std::shared_ptr<FuncRequest const> func,
+	Action(std::shared_ptr<FuncRequest const> const & func,
 	       QIcon const & icon, QString const & text,
 	       QString const & tooltip, QObject * parent);
 
diff --git a/src/frontends/qt/TocModel.cpp b/src/frontends/qt/TocModel.cpp
index c0c3dce548..ab37c987cd 100644
--- a/src/frontends/qt/TocModel.cpp
+++ b/src/frontends/qt/TocModel.cpp
@@ -160,7 +160,7 @@ void TocModel::updateItem(DocIterator const & dit)
 }
 
 
-void TocModel::reset(shared_ptr<Toc const> toc)
+void TocModel::reset(shared_ptr<Toc const> const & toc)
 {
 	toc_ = toc;
 	if (toc_->empty()) {
diff --git a/src/frontends/qt/TocModel.h b/src/frontends/qt/TocModel.h
index ee447616d0..b37484fcc6 100644
--- a/src/frontends/qt/TocModel.h
+++ b/src/frontends/qt/TocModel.h
@@ -39,7 +39,7 @@ public:
 	///
 	TocModel(QObject * parent);
 	///
-	void reset(std::shared_ptr<Toc const>);
+	void reset(std::shared_ptr<Toc const> const &);
 	///
 	void reset();
 	///
diff --git a/src/support/FileMonitor.cpp b/src/support/FileMonitor.cpp
index 4a81cc2fc8..3d007ba96c 100644
--- a/src/support/FileMonitor.cpp
+++ b/src/support/FileMonitor.cpp
@@ -158,7 +158,7 @@ void FileMonitorGuard::notifyChange(QString const & path)
 }
 
 
-FileMonitor::FileMonitor(std::shared_ptr<FileMonitorGuard> monitor)
+FileMonitor::FileMonitor(std::shared_ptr<FileMonitorGuard> const & monitor)
 	: monitor_(monitor)
 {
 	connectToFileMonitorGuard();
@@ -193,7 +193,7 @@ void FileMonitor::changed(bool const exists)
 }
 
 
-ActiveFileMonitor::ActiveFileMonitor(std::shared_ptr<FileMonitorGuard> monitor,
+ActiveFileMonitor::ActiveFileMonitor(std::shared_ptr<FileMonitorGuard> const & monitor,
                                      FileName const & filename, int interval)
 	: FileMonitor(monitor), filename_(filename), interval_(interval),
 	  timestamp_(0), checksum_(0), cooldown_(true)
diff --git a/src/support/FileMonitor.h b/src/support/FileMonitor.h
index 1e43979de4..2b34c7a90f 100644
--- a/src/support/FileMonitor.h
+++ b/src/support/FileMonitor.h
@@ -128,7 +128,7 @@ class FileMonitor : public QObject
 	Q_OBJECT
 
 public:
-	FileMonitor(std::shared_ptr<FileMonitorGuard> monitor);
+	FileMonitor(std::shared_ptr<FileMonitorGuard> const & monitor);
 
 	typedef signal<void(bool)> sig;
 	typedef sig::slot_type slot;
@@ -166,7 +166,7 @@ class ActiveFileMonitor : public FileMonitor
 {
 	Q_OBJECT
 public:
-	ActiveFileMonitor(std::shared_ptr<FileMonitorGuard> monitor,
+	ActiveFileMonitor(std::shared_ptr<FileMonitorGuard> const & monitor,
 	                  FileName const & filename, int interval);
 	/// call checkModified asynchronously
 	void checkModifiedAsync();