diff --git a/src/plugins/cppeditor/cppsourceprocessor.cpp b/src/plugins/cppeditor/cppsourceprocessor.cpp
index 1c8c79a2c2c..4cdc6962416 100644
--- a/src/plugins/cppeditor/cppsourceprocessor.cpp
+++ b/src/plugins/cppeditor/cppsourceprocessor.cpp
@@ -364,9 +364,7 @@ void CppSourceProcessor::mergeEnvironment(Document::Ptr doc)
     if (!doc)
         return;
 
-    const QString fn = doc->filePath().path();
-
-    if (!Utils::insert(m_processed, fn))
+    if (!Utils::insert(m_processed, doc->filePath()))
         return;
 
     const QList<Document::Include> includes = doc->resolvedIncludes();
diff --git a/src/plugins/cppeditor/cppsourceprocessor.h b/src/plugins/cppeditor/cppsourceprocessor.h
index 75ea0fa8d21..d5a2763e30d 100644
--- a/src/plugins/cppeditor/cppsourceprocessor.h
+++ b/src/plugins/cppeditor/cppsourceprocessor.h
@@ -96,7 +96,7 @@ private:
     QSet<Utils::FilePath> m_included;
     CPlusPlus::Document::Ptr m_currentDoc;
     QSet<QString> m_todo;
-    QSet<QString> m_processed;
+    QSet<Utils::FilePath> m_processed;
     QHash<Utils::FilePath, Utils::FilePath> m_fileNameCache;
     int m_fileSizeLimitInMb = -1;
     QTextCodec *m_defaultCodec;