diff --git a/src/libs/cplusplus/cppmodelmanagerbase.cpp b/src/libs/cplusplus/cppmodelmanagerbase.cpp
index cff9ef99e2c..410244ab96f 100644
--- a/src/libs/cplusplus/cppmodelmanagerbase.cpp
+++ b/src/libs/cplusplus/cppmodelmanagerbase.cpp
@@ -3,29 +3,32 @@
 
 #include "cppmodelmanagerbase.h"
 
+#include <utils/filepath.h>
 #include <utils/qtcassert.h>
 
+using namespace Utils;
+
 namespace CPlusPlus::CppModelManagerBase {
 
 static bool (*setExtraDiagnosticsCallback)
-    (const QString &, const QString &, const QList<Document::DiagnosticMessage> &) = nullptr;
+    (const FilePath &, const QString &, const QList<Document::DiagnosticMessage> &) = nullptr;
 
 static CPlusPlus::Snapshot (*snapshotCallback)() = nullptr;
 
 
-bool trySetExtraDiagnostics(const QString &fileName, const QString &kind,
+bool trySetExtraDiagnostics(const FilePath &filePath, const QString &kind,
                             const QList<Document::DiagnosticMessage> &diagnostics)
 {
     if (!setExtraDiagnosticsCallback)
         return false;
-    return setExtraDiagnosticsCallback(fileName, kind, diagnostics);
+    return setExtraDiagnosticsCallback(filePath, kind, diagnostics);
 }
 
-bool setExtraDiagnostics(const QString &fileName, const QString &kind,
-                            const QList<Document::DiagnosticMessage> &diagnostics)
+bool setExtraDiagnostics(const FilePath &filePath, const QString &kind,
+                         const QList<Document::DiagnosticMessage> &diagnostics)
 {
     QTC_ASSERT(setExtraDiagnosticsCallback, return false);
-    return setExtraDiagnosticsCallback(fileName, kind, diagnostics);
+    return setExtraDiagnosticsCallback(filePath, kind, diagnostics);
 }
 
 Snapshot snapshot()
@@ -42,7 +45,7 @@ bool hasSnapshots()
 // Installation
 
 void registerSetExtraDiagnosticsCallback(
-    bool (*callback)(const QString &, const QString &, const QList<Document::DiagnosticMessage> &))
+    bool (*callback)(const FilePath &, const QString &, const QList<Document::DiagnosticMessage> &))
 {
     QTC_ASSERT(callback, return);
     QTC_CHECK(!setExtraDiagnosticsCallback); // bark when used twice
diff --git a/src/libs/cplusplus/cppmodelmanagerbase.h b/src/libs/cplusplus/cppmodelmanagerbase.h
index 1a9e4c7db33..0a8e18e733f 100644
--- a/src/libs/cplusplus/cppmodelmanagerbase.h
+++ b/src/libs/cplusplus/cppmodelmanagerbase.h
@@ -5,13 +5,15 @@
 
 #include <cplusplus/CppDocument.h>
 
+namespace Utils { class FilePath; }
+
 namespace CPlusPlus::CppModelManagerBase {
 
 CPLUSPLUS_EXPORT bool trySetExtraDiagnostics
-    (const QString &, const QString &, const QList<Document::DiagnosticMessage> &);
+    (const Utils::FilePath &filePath, const QString &, const QList<Document::DiagnosticMessage> &);
 
 CPLUSPLUS_EXPORT bool setSetExtraDiagnostics
-    (const QString &, const QString &, const QList<Document::DiagnosticMessage> &);
+    (const Utils::FilePath &, const QString &, const QList<Document::DiagnosticMessage> &);
 
 CPLUSPLUS_EXPORT bool hasSnapshots();
 
@@ -23,6 +25,6 @@ CPLUSPLUS_EXPORT CPlusPlus::Snapshot snapshot();
 CPLUSPLUS_EXPORT void registerSnapshotCallback(CPlusPlus::Snapshot (*)(void));
 
 CPLUSPLUS_EXPORT void registerSetExtraDiagnosticsCallback(
-    bool(*)(const QString &, const QString &, const QList<Document::DiagnosticMessage> &));
+    bool(*)(const Utils::FilePath &, const QString &, const QList<Document::DiagnosticMessage> &));
 
 } // CPlusPlus::CppModelManagerBase
diff --git a/src/libs/qmljs/qmljsfindexportedcpptypes.cpp b/src/libs/qmljs/qmljsfindexportedcpptypes.cpp
index e3c5cb6fc76..6b2c10b21a8 100644
--- a/src/libs/qmljs/qmljsfindexportedcpptypes.cpp
+++ b/src/libs/qmljs/qmljsfindexportedcpptypes.cpp
@@ -842,8 +842,7 @@ QStringList FindExportedCppTypes::operator()(const CPlusPlus::Document::Ptr &doc
     FindExportsVisitor finder(document);
     finder();
     static const QString kindKey = QLatin1String("QmlJSTools.ExportedQmlTypesDiagnostic");
-    CppModelManagerBase::trySetExtraDiagnostics(document->filePath().toString(), kindKey,
-                                                finder.messages());
+    CppModelManagerBase::trySetExtraDiagnostics(document->filePath(), kindKey, finder.messages());
 
     // if nothing was found, done
     const QList<ContextProperty> contextPropertyDescriptions = finder.contextProperties();
diff --git a/src/plugins/cppeditor/cppeditordocument.cpp b/src/plugins/cppeditor/cppeditordocument.cpp
index e03dc2b40fe..da9eaed9b87 100644
--- a/src/plugins/cppeditor/cppeditordocument.cpp
+++ b/src/plugins/cppeditor/cppeditordocument.cpp
@@ -479,9 +479,9 @@ bool CppEditorDocument::usesClangd() const
     return CppModelManager::usesClangd(this);
 }
 
-void CppEditorDocument::onDiagnosticsChanged(const QString &fileName, const QString &kind)
+void CppEditorDocument::onDiagnosticsChanged(const FilePath &fileName, const QString &kind)
 {
-    if (FilePath::fromString(fileName) != filePath())
+    if (fileName != filePath())
         return;
 
     TextMarks removedMarks = marks();
diff --git a/src/plugins/cppeditor/cppeditordocument.h b/src/plugins/cppeditor/cppeditordocument.h
index 734c64b665f..7a0a8f43cc5 100644
--- a/src/plugins/cppeditor/cppeditordocument.h
+++ b/src/plugins/cppeditor/cppeditordocument.h
@@ -76,7 +76,7 @@ private:
 
     void onAboutToReload();
     void onReloadFinished();
-    void onDiagnosticsChanged(const QString &fileName, const QString &kind);
+    void onDiagnosticsChanged(const Utils::FilePath &fileName, const QString &kind);
 
 
     void reparseWithPreferredParseContext(const QString &id);
diff --git a/src/plugins/cppeditor/cppmodelmanager.cpp b/src/plugins/cppeditor/cppmodelmanager.cpp
index 3980f99ac89..c95567eb3b6 100644
--- a/src/plugins/cppeditor/cppmodelmanager.cpp
+++ b/src/plugins/cppeditor/cppmodelmanager.cpp
@@ -2079,12 +2079,12 @@ QThreadPool *CppModelManager::sharedThreadPool()
     return &d->m_threadPool;
 }
 
-bool CppModelManager::setExtraDiagnostics(const QString &fileName,
+bool CppModelManager::setExtraDiagnostics(const FilePath &filePath,
                                           const QString &kind,
                                           const QList<Document::DiagnosticMessage> &diagnostics)
 {
     d->m_diagnosticMessages = diagnostics;
-    emit m_instance->diagnosticsChanged(fileName, kind);
+    emit m_instance->diagnosticsChanged(filePath, kind);
     return true;
 }
 
diff --git a/src/plugins/cppeditor/cppmodelmanager.h b/src/plugins/cppeditor/cppmodelmanager.h
index 6f6dc7298e3..2e78042eb79 100644
--- a/src/plugins/cppeditor/cppmodelmanager.h
+++ b/src/plugins/cppeditor/cppmodelmanager.h
@@ -95,7 +95,7 @@ public:
     static QByteArray codeModelConfiguration();
     static CppLocatorData *locatorData();
 
-    static bool setExtraDiagnostics(const QString &fileName,
+    static bool setExtraDiagnostics(const Utils::FilePath &filePath,
                                     const QString &kind,
                                     const QList<Document::DiagnosticMessage> &diagnostics);
 
@@ -268,7 +268,7 @@ signals:
     void abstractEditorSupportRemoved(const QString &filePath);
     void fallbackProjectPartUpdated();
 
-    void diagnosticsChanged(const QString &fileName, const QString &kind);
+    void diagnosticsChanged(const Utils::FilePath &filePath, const QString &kind);
 
 public slots:
     static void updateModifiedSourceFiles();