diff --git a/gui/projectfile.cpp b/gui/projectfile.cpp
index 611848c79..9ff0d79a3 100644
--- a/gui/projectfile.cpp
+++ b/gui/projectfile.cpp
@@ -316,22 +316,22 @@ void ProjectFile::ReadIgnores(QXmlStreamReader &reader)
     while (!allRead);
 }
 
-void ProjectFile::SetIncludes(QStringList includes)
+void ProjectFile::SetIncludes(const QStringList &includes)
 {
     mIncludeDirs = includes;
 }
 
-void ProjectFile::SetDefines(QStringList defines)
+void ProjectFile::SetDefines(const QStringList &defines)
 {
     mDefines = defines;
 }
 
-void ProjectFile::SetCheckPaths(QStringList paths)
+void ProjectFile::SetCheckPaths(const QStringList &paths)
 {
     mPaths = paths;
 }
 
-void ProjectFile::SetIgnoredPaths(QStringList paths)
+void ProjectFile::SetIgnoredPaths(const QStringList &paths)
 {
     mIgnoredPaths = paths;
 }
diff --git a/gui/projectfile.h b/gui/projectfile.h
index 8fe2efb93..2986f11a7 100644
--- a/gui/projectfile.h
+++ b/gui/projectfile.h
@@ -93,25 +93,25 @@ public:
     * @brief Set list of includes.
     * @param includes List of defines.
     */
-    void SetIncludes(QStringList includes);
+    void SetIncludes(const QStringList &includes);
 
     /**
     * @brief Set list of defines.
     * @param defines List of defines.
     */
-    void SetDefines(QStringList defines);
+    void SetDefines(const QStringList &defines);
 
     /**
     * @brief Set list of paths to check.
     * @param defines List of paths.
     */
-    void SetCheckPaths(QStringList paths);
+    void SetCheckPaths(const QStringList &paths);
 
     /**
     * @brief Set list of paths to ignore.
     * @param defines List of paths.
     */
-    void SetIgnoredPaths(QStringList paths);
+    void SetIgnoredPaths(const QStringList &paths);
 
     /**
     * @brief Write project file (to disk).