diff --git a/src/plugins/projectexplorer/project.h b/src/plugins/projectexplorer/project.h
index 7eca3cc0645..ab9b55cd47d 100644
--- a/src/plugins/projectexplorer/project.h
+++ b/src/plugins/projectexplorer/project.h
@@ -174,7 +174,6 @@ public:
 
     void setDisplayName(const QString &name);
     void setProjectLanguage(Utils::Id id, bool enabled);
-    void addProjectLanguage(Utils::Id id);
 
     void setExtraData(const QString &key, const QVariant &data);
     QVariant extraData(const QString &key) const;
@@ -221,7 +220,6 @@ protected:
 
     void setId(Utils::Id id);
     void setProjectLanguages(Core::Context language);
-    void removeProjectLanguage(Utils::Id id);
     void setHasMakeInstallEquivalent(bool enabled);
 
     void setNeedsBuildConfigurations(bool value);
@@ -235,6 +233,9 @@ protected:
 private:
     void addTarget(std::unique_ptr<Target> &&target);
 
+    void addProjectLanguage(Utils::Id id);
+    void removeProjectLanguage(Utils::Id id);
+
     void handleSubTreeChanged(FolderNode *node);
     void setActiveTarget(Target *target);
 
diff --git a/src/plugins/qmakeprojectmanager/qmakeproject.cpp b/src/plugins/qmakeprojectmanager/qmakeproject.cpp
index 35be824145d..b339cc07cd1 100644
--- a/src/plugins/qmakeprojectmanager/qmakeproject.cpp
+++ b/src/plugins/qmakeprojectmanager/qmakeproject.cpp
@@ -454,8 +454,7 @@ void QmakeBuildSystem::updateQmlJSCodeModel()
     // library then chances of the project being a QML project is quite high.
     // This assumption fails when there are no QDeclarativeEngine/QDeclarativeView (QtQuick 1)
     // or QQmlEngine/QQuickView (QtQuick 2) instances.
-    if (hasQmlLib)
-        project()->addProjectLanguage(ProjectExplorer::Constants::QMLJS_LANGUAGE_ID);
+    project()->setProjectLanguage(ProjectExplorer::Constants::QMLJS_LANGUAGE_ID, hasQmlLib);
 
     projectInfo.activeResourceFiles.removeDuplicates();
     projectInfo.allResourceFiles.removeDuplicates();