diff --git a/src/libs/utils/fileutils.h b/src/libs/utils/fileutils.h
index 50e69c2fc44..492c0b636b6 100644
--- a/src/libs/utils/fileutils.h
+++ b/src/libs/utils/fileutils.h
@@ -96,11 +96,9 @@ public:
     FileName &appendString(QChar str);
 
     using QString::clear;
-    using QString::count;
     using QString::isEmpty;
     using QString::isNull;
-    using QString::length;
-    using QString::size;
+
 private:
     FileName(const QString &string);
 };
diff --git a/src/plugins/cppcheck/cppcheckrunner.cpp b/src/plugins/cppcheck/cppcheckrunner.cpp
index f67044cb678..55f7472ef60 100644
--- a/src/plugins/cppcheck/cppcheckrunner.cpp
+++ b/src/plugins/cppcheck/cppcheckrunner.cpp
@@ -140,7 +140,7 @@ void CppcheckRunner::checkQueued()
     m_currentFiles.clear();
     int argumentsLength = arguments.length();
     while (!files.isEmpty()) {
-        argumentsLength += files.first().length() + 1; // +1 for separator
+        argumentsLength += files.first().toString().size() + 1; // +1 for separator
         if (argumentsLength >= m_maxArgumentsLength)
             break;
         m_currentFiles.push_back(files.first());
diff --git a/src/plugins/projectexplorer/foldernavigationwidget.cpp b/src/plugins/projectexplorer/foldernavigationwidget.cpp
index b41ae6b0f9a..1da235b7fa9 100644
--- a/src/plugins/projectexplorer/foldernavigationwidget.cpp
+++ b/src/plugins/projectexplorer/foldernavigationwidget.cpp
@@ -655,9 +655,9 @@ int FolderNavigationWidget::bestRootForFile(const Utils::FileName &filePath)
     int commonLength = 0;
     for (int i = 1; i < m_rootSelector->count(); ++i) {
         const auto root = m_rootSelector->itemData(i).value<Utils::FileName>();
-        if (filePath.isChildOf(root) && root.length() > commonLength) {
+        if (filePath.isChildOf(root) && root.toString().size() > commonLength) {
             index = i;
-            commonLength = root.length();
+            commonLength = root.toString().size();
         }
     }
     return index;