diff --git a/src/plugins/projectexplorer/toolchainoptionspage.cpp b/src/plugins/projectexplorer/toolchainoptionspage.cpp
index b44800a8ab9..db068687e1c 100644
--- a/src/plugins/projectexplorer/toolchainoptionspage.cpp
+++ b/src/plugins/projectexplorer/toolchainoptionspage.cpp
@@ -550,7 +550,8 @@ void ToolChainOptionsWidget::apply()
     Q_ASSERT(m_toRemoveList.isEmpty());
 
     // Update tool chains:
-    for (const QPair<StaticTreeItem *, StaticTreeItem *> &autoAndManual : m_languageMap) {
+    for (const QPair<StaticTreeItem *, StaticTreeItem *> &autoAndManual :
+         std::as_const(m_languageMap)) {
         for (StaticTreeItem *parent : {autoAndManual.first, autoAndManual.second}) {
             for (TreeItem *item : *parent) {
                 auto tcItem = static_cast<ExtendedToolchainTreeItem *>(item);