diff --git a/src/plugins/cmakeprojectmanager/cmakeopenprojectwizard.cpp b/src/plugins/cmakeprojectmanager/cmakeopenprojectwizard.cpp
index 4a4e2ff6426745a45f28e2161710e5360fa7e87a..5d5b30d72ad981bcd823500026d2a0fc0a693c87 100644
--- a/src/plugins/cmakeprojectmanager/cmakeopenprojectwizard.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakeopenprojectwizard.cpp
@@ -638,7 +638,7 @@ void CMakeRunPage::runCMake()
     }
 }
 
-static QColor mix_colors(QColor a, QColor b)
+static QColor mix_colors(const QColor &a, const QColor &b)
 {
     return QColor((a.red() + 2 * b.red()) / 3, (a.green() + 2 * b.green()) / 3,
                   (a.blue() + 2* b.blue()) / 3, (a.alpha() + 2 * b.alpha()) / 3);