CPlusPlus: Proliferate FilePath use

The starts with CppDocument::filePath(), plus a bit of the fallout

This is one patch of potentially many. It is hard to draw the
line where to stop this kind of chunk, this here converts a few
additional functions for which including it in the patch looked
like less churn than without.

Converting is mostly fromString/toString, with a few exceptions
for "already seem" like caches, that use cheaper "path()" to
avoid likely performance regressions (on Windows FilePath
comparison is currently case-insenstive, and more expensive).

There should be no difference for local operation with this patch.

Change-Id: I7b35f98a0a6f0bfed4ea0f8f987faf586f7a8f2b
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

66 files changed, 340 insertions, 308 deletions

diff --git a/src/libs/cplusplus/CppDocument.cpp b/src/libs/cplusplus/CppDocument.cpp
index 12ce8ea0cd3..6362bf06593 100644
--- a/src/libs/cplusplus/CppDocument.cpp
+++ b/src/libs/cplusplus/CppDocument.cpp
@@ -205,7 +205,7 @@ public:
 
         const QString fileName = QString::fromUtf8(fileId->chars(), fileId->size());
 
-        if (fileName != doc->fileName())
+        if (fileName != doc->filePath().pathView())
             return;
 
         const QString message = QString::vasprintf(format, ap);
@@ -220,7 +220,7 @@ public:
         }
 #endif // DO_NOT_DUMP_ALL_PARSER_ERRORS
 
-        Document::DiagnosticMessage m(convertLevel(level), doc->fileName(),
+        Document::DiagnosticMessage m(convertLevel(level), doc->filePath(),
                                       line, column, message);
         messages->append(m);
     }
@@ -244,7 +244,7 @@ private:
 
 
 Document::Document(const QString &fileName)
-    : _fileName(QDir::cleanPath(fileName)),
+    : _filePath(Utils::FilePath::fromUserInput(QDir::cleanPath(fileName))),
       _globalNamespace(nullptr),
       _revision(0),
       _editorRevision(0),
@@ -652,7 +652,7 @@ bool Document::DiagnosticMessage::operator==(const Document::DiagnosticMessage &
             _column == other._column &&
             _length == other._length &&
             _level == other._level &&
-            _fileName == other._fileName &&
+            _filePath == other._filePath &&
             _text == other._text;
 }
 
@@ -697,7 +697,7 @@ bool Snapshot::contains(const Utils::FilePath &fileName) const
 void Snapshot::insert(Document::Ptr doc)
 {
     if (doc) {
-        _documents.insert(Utils::FilePath::fromString(doc->fileName()), doc);
+        _documents.insert(doc->filePath(), doc);
         m_deps.files.clear(); // Will trigger re-build when accessed.
     }
 }
@@ -848,7 +848,7 @@ Snapshot Snapshot::simplified(Document::Ptr doc) const
 
     if (doc) {
         snapshot.insert(doc);
-        const QSet<QString> fileNames = allIncludesForDocument(doc->fileName());
+        const QSet<QString> fileNames = allIncludesForDocument(doc->filePath().toString());
         for (const QString &fileName : fileNames)
             if (Document::Ptr inc = document(fileName))
                 snapshot.insert(inc);
diff --git a/src/libs/cplusplus/CppDocument.h b/src/libs/cplusplus/CppDocument.h
index c3ee363f261..fd98098763f 100644
--- a/src/libs/cplusplus/CppDocument.h
+++ b/src/libs/cplusplus/CppDocument.h
@@ -49,7 +49,7 @@ public:
     const QDateTime &lastModified() const { return _lastModified; }
     void setLastModified(const QDateTime &lastModified);
 
-    const QString &fileName() const { return _fileName; }
+    const Utils::FilePath &filePath() const { return _filePath; }
 
     void appendMacro(const Macro &macro);
     void addMacroUse(const Macro &macro,
@@ -125,13 +125,13 @@ public:
         };
 
     public:
-        DiagnosticMessage(int level, const QString &fileName,
+        DiagnosticMessage(int level, const Utils::FilePath &filePath,
                           int line, int column,
                           const QString &text,
                           int length = 0)
             : _level(level),
               _line(line),
-              _fileName(fileName),
+              _filePath(filePath),
               _column(column),
               _length(length),
               _text(text)
@@ -149,8 +149,8 @@ public:
         bool isFatal() const
         { return _level == Fatal; }
 
-        const QString &fileName() const
-        { return _fileName; }
+        const Utils::FilePath &filePath() const
+        { return _filePath; }
 
         int line() const
         { return _line; }
@@ -170,7 +170,7 @@ public:
     private:
         int _level;
         int _line;
-        QString _fileName;
+        Utils::FilePath _filePath;
         int _column;
         int _length;
         QString _text;
@@ -334,7 +334,7 @@ public:
     { return static_cast<CheckMode>(_checkMode); }
 
 private:
-    QString _fileName;
+    Utils::FilePath _filePath;
     Control *_control;
     TranslationUnit *_translationUnit;
     Namespace *_globalNamespace;
diff --git a/src/libs/cplusplus/FastPreprocessor.cpp b/src/libs/cplusplus/FastPreprocessor.cpp
index fb89ed26bf3..607dd55364b 100644
--- a/src/libs/cplusplus/FastPreprocessor.cpp
+++ b/src/libs/cplusplus/FastPreprocessor.cpp
@@ -8,6 +8,7 @@
 
 #include <QDir>
 
+using namespace Utils;
 using namespace CPlusPlus;
 
 FastPreprocessor::FastPreprocessor(const Snapshot &snapshot)
@@ -23,12 +24,12 @@ QByteArray FastPreprocessor::run(Document::Ptr newDoc,
     std::swap(newDoc, _currentDoc);
     _addIncludesToCurrentDoc = _currentDoc->resolvedIncludes().isEmpty()
             && _currentDoc->unresolvedIncludes().isEmpty();
-    const QString fileName = _currentDoc->fileName();
+    const FilePath filePath = _currentDoc->filePath();
     _preproc.setExpandFunctionlikeMacros(false);
     _preproc.setKeepComments(true);
 
-    if (Document::Ptr doc = _snapshot.document(fileName)) {
-        _merged.insert(fileName);
+    if (Document::Ptr doc = _snapshot.document(filePath)) {
+        _merged.insert(filePath.toString());
 
         for (Snapshot::const_iterator i = _snapshot.begin(), ei = _snapshot.end(); i != ei; ++i) {
             if (isInjectedFile(i.key().toString()))
@@ -43,7 +44,7 @@ QByteArray FastPreprocessor::run(Document::Ptr newDoc,
             _env.addMacros(_currentDoc->definedMacros());
     }
 
-    const QByteArray preprocessed = _preproc.run(fileName, source);
+    const QByteArray preprocessed = _preproc.run(filePath, source);
 //    qDebug("FastPreprocessor::run for %s produced [[%s]]", fileName.toUtf8().constData(), preprocessed.constData());
     std::swap(newDoc, _currentDoc);
     return preprocessed;
diff --git a/src/libs/cplusplus/FindUsages.cpp b/src/libs/cplusplus/FindUsages.cpp
index 6e1731ca118..4928c4f7712 100644
--- a/src/libs/cplusplus/FindUsages.cpp
+++ b/src/libs/cplusplus/FindUsages.cpp
@@ -118,7 +118,7 @@ void FindUsages::reportResult(unsigned tokenIndex, const QList<LookupItem> &cand
         lineText = matchingLine(tk);
     const int len = tk.utf16chars();
 
-    const Usage u(Utils::FilePath::fromString(_doc->fileName()), lineText,
+    const Usage u(_doc->filePath(), lineText,
                   getContainingFunction(line, col), getTags(line, col, tokenIndex),
                   line, col - 1, len);
     _usages.append(u);
diff --git a/src/libs/cplusplus/SnapshotSymbolVisitor.cpp b/src/libs/cplusplus/SnapshotSymbolVisitor.cpp
index 0c459aa373d..4692c25108b 100644
--- a/src/libs/cplusplus/SnapshotSymbolVisitor.cpp
+++ b/src/libs/cplusplus/SnapshotSymbolVisitor.cpp
@@ -20,8 +20,8 @@ void SnapshotSymbolVisitor::accept(Document::Ptr doc)
 
 void SnapshotSymbolVisitor::accept(Document::Ptr doc, QSet<QString> *processed)
 {
-    if (doc && doc->globalNamespace() && ! processed->contains(doc->fileName())) {
-        processed->insert(doc->fileName());
+    if (doc && doc->globalNamespace() && ! processed->contains(doc->filePath().path())) {
+        processed->insert(doc->filePath().path());
 
         const QList<Document::Include> includes = doc->resolvedIncludes();
         for (const Document::Include &i : includes) {
diff --git a/src/libs/cplusplus/TypeOfExpression.cpp b/src/libs/cplusplus/TypeOfExpression.cpp
index 88efe41695d..2453ad829ff 100644
--- a/src/libs/cplusplus/TypeOfExpression.cpp
+++ b/src/libs/cplusplus/TypeOfExpression.cpp
@@ -13,7 +13,7 @@
 
 #include <QSet>
 
-using namespace CPlusPlus;
+namespace CPlusPlus {
 
 TypeOfExpression::TypeOfExpression():
     m_ast(nullptr),
@@ -132,8 +132,8 @@ ExpressionAST *TypeOfExpression::expressionAST() const
 void TypeOfExpression::processEnvironment(Document::Ptr doc, Environment *env,
                                           QSet<QString> *processed) const
 {
-    if (doc && ! processed->contains(doc->fileName())) {
-        processed->insert(doc->fileName());
+    if (doc && ! processed->contains(doc->filePath().path())) {
+        processed->insert(doc->filePath().path());
 
         const QList<Document::Include> includes = doc->resolvedIncludes();
         for (const Document::Include &incl : includes)
@@ -158,11 +158,9 @@ QByteArray TypeOfExpression::preprocessedExpression(const QByteArray &utf8code)
     }
 
     Preprocessor preproc(nullptr, m_environment.data());
-    return preproc.run(QLatin1String("<expression>"), utf8code);
+    return preproc.run(Utils::FilePath::fromParts({}, {}, u"<expression>"), utf8code);
 }
 
-namespace CPlusPlus {
-
 ExpressionAST *extractExpressionAST(Document::Ptr doc)
 {
     if (! doc->translationUnit()->ast())
diff --git a/src/libs/cplusplus/pp-engine.cpp b/src/libs/cplusplus/pp-engine.cpp
index 836e2ad05b7..58fa33b0a9e 100644
--- a/src/libs/cplusplus/pp-engine.cpp
+++ b/src/libs/cplusplus/pp-engine.cpp
@@ -31,6 +31,7 @@
 #include <cplusplus/cppassert.h>
 
 #include <utils/executeondestruction.h>
+#include <utils/filepath.h>
 #include <utils/scopedswap.h>
 
 #include <QDebug>
@@ -235,7 +236,6 @@ struct Value
 };
 
 } // namespace Internal
-} // namespace CPlusPlus
 
 using namespace CPlusPlus;
 using namespace CPlusPlus::Internal;
@@ -251,7 +251,7 @@ Macro *macroDefinition(const ByteArrayRef &name,
                        unsigned bytesOffset,
                        unsigned utf16charsOffset,
                        unsigned line,
-                       Environment *env,
+                       CPlusPlus::Environment *env,
                        Client *client)
 {
     Macro *m = env->resolve(name);
@@ -320,7 +320,7 @@ class ExpressionEvaluator
     void operator = (const ExpressionEvaluator &other);
 
 public:
-    ExpressionEvaluator(Client *client, Environment *env)
+    ExpressionEvaluator(Client *client, CPlusPlus::Environment *env)
         : client(client), env(env), _lex(nullptr)
     { }
 
@@ -726,6 +726,14 @@ Preprocessor::Preprocessor(Client *client, Environment *env)
 {
 }
 
+QByteArray Preprocessor::run(const Utils::FilePath &filePath,
+                             const QByteArray &source,
+                             bool noLines,
+                             bool markGeneratedTokens)
+{
+    return run(filePath.toString(), source, noLines, markGeneratedTokens);
+}
+
 QByteArray Preprocessor::run(const QString &fileName,
                              const QByteArray &source,
                              bool noLines,
@@ -2158,3 +2166,5 @@ void Preprocessor::maybeStartOutputLine()
     if (*ch == '\\')
         buffer.append('\n');
 }
+
+} // namespace CPlusPlus
diff --git a/src/libs/cplusplus/pp-engine.h b/src/libs/cplusplus/pp-engine.h
index 4cbda7162c3..f5c2474ffc7 100644
--- a/src/libs/cplusplus/pp-engine.h
+++ b/src/libs/cplusplus/pp-engine.h
@@ -36,6 +36,8 @@
 
 #include <functional>
 
+namespace Utils { class FilePath; }
+
 namespace CPlusPlus {
 
 class Environment;
@@ -57,6 +59,8 @@ public:
 public:
     Preprocessor(Client *client, Environment *env);
 
+    QByteArray run(const Utils::FilePath &filePath, const QByteArray &source,
+                   bool noLines = false, bool markGeneratedTokens = true);
     QByteArray run(const QString &filename, const QByteArray &source,
                    bool noLines = false, bool markGeneratedTokens = true);
 
diff --git a/src/libs/qmljs/qmljsfindexportedcpptypes.cpp b/src/libs/qmljs/qmljsfindexportedcpptypes.cpp
index 2e07d91f22c..427a73ef3f8 100644
--- a/src/libs/qmljs/qmljsfindexportedcpptypes.cpp
+++ b/src/libs/qmljs/qmljsfindexportedcpptypes.cpp
@@ -248,7 +248,7 @@ protected:
             translationUnit()->getTokenStartPosition(nameExp->firstToken(), &line, &column);
             _messages += Document::DiagnosticMessage(
                         Document::DiagnosticMessage::Warning,
-                        _doc->fileName(),
+                        _doc->filePath(),
                         line, column,
                         QmlJS::FindExportedCppTypes::tr(
                             "The type will only be available in the QML editors when the type name is a string literal."));
@@ -309,7 +309,7 @@ protected:
             translationUnit()->getTokenStartPosition(ast->firstToken(), &line, &column);
             _messages += Document::DiagnosticMessage(
                         Document::DiagnosticMessage::Warning,
-                        _doc->fileName(),
+                        _doc->filePath(),
                         line, column,
                         QmlJS::FindExportedCppTypes::tr(
                             "The module URI cannot be determined by static analysis. The type will not be available\n"
@@ -491,7 +491,7 @@ protected:
             translationUnit()->getTokenStartPosition(ast->expression_list->value->firstToken(), &line, &column);
             _messages += Document::DiagnosticMessage(
                         Document::DiagnosticMessage::Warning,
-                        _doc->fileName(),
+                        _doc->filePath(),
                         line, column,
                         QmlJS::FindExportedCppTypes::tr(
                             "must be a string literal to be available in the QML editor"));
@@ -840,7 +840,7 @@ QStringList FindExportedCppTypes::operator()(const CPlusPlus::Document::Ptr &doc
     FindExportsVisitor finder(document);
     finder();
     static const QString kindKey = QLatin1String("QmlJSTools.ExportedQmlTypesDiagnostic");
-    CppModelManagerBase::trySetExtraDiagnostics(document->fileName(), kindKey,
+    CppModelManagerBase::trySetExtraDiagnostics(document->filePath().toString(), kindKey,
                                                 finder.messages());
 
     // if nothing was found, done
@@ -852,7 +852,8 @@ QStringList FindExportedCppTypes::operator()(const CPlusPlus::Document::Ptr &doc
     // context properties need lookup inside function scope, and thus require a full check
     CPlusPlus::Document::Ptr localDoc = document;
     if (document->checkMode() != CPlusPlus::Document::FullCheck && !contextPropertyDescriptions.isEmpty()) {
-        localDoc = m_snapshot.documentFromSource(document->utf8Source(), document->fileName());
+        localDoc = m_snapshot.documentFromSource(document->utf8Source(),
+                                                 document->filePath().toString());
         localDoc->check();
     }
 
diff --git a/src/libs/qmljs/qmljsmodelmanagerinterface.cpp b/src/libs/qmljs/qmljsmodelmanagerinterface.cpp
index 70eebf6faf6..71bd55119be 100644
--- a/src/libs/qmljs/qmljsmodelmanagerinterface.cpp
+++ b/src/libs/qmljs/qmljsmodelmanagerinterface.cpp
@@ -1350,10 +1350,10 @@ void ModelManagerInterface::maybeQueueCppQmlTypeUpdate(const CPlusPlus::Document
 
 void ModelManagerInterface::queueCppQmlTypeUpdate(const CPlusPlus::Document::Ptr &doc, bool scan)
 {
-    QPair<CPlusPlus::Document::Ptr, bool> prev = m_queuedCppDocuments.value(doc->fileName());
+    QPair<CPlusPlus::Document::Ptr, bool> prev = m_queuedCppDocuments.value(doc->filePath().path());
     if (prev.first && prev.second)
         prev.first->releaseSourceAndAST();
-    m_queuedCppDocuments.insert(doc->fileName(), {doc, scan});
+    m_queuedCppDocuments.insert(doc->filePath().path(), {doc, scan});
     m_updateCppQmlTypesTimer->start();
 }
 
@@ -1439,13 +1439,13 @@ void ModelManagerInterface::updateCppQmlTypes(
 
         CPlusPlus::Document::Ptr doc = pair.first;
         const bool scan = pair.second;
-        const QString fileName = doc->fileName();
+        const FilePath filePath = doc->filePath();
         if (!scan) {
-            hasNewInfo = newData.remove(fileName) || hasNewInfo;
-            const auto savedDocs = newDeclarations.value(fileName);
+            hasNewInfo = newData.remove(filePath.path()) || hasNewInfo;
+            const auto savedDocs = newDeclarations.value(filePath.path());
             for (const CPlusPlus::Document::Ptr &savedDoc : savedDocs) {
                 finder(savedDoc);
-                hasNewInfo = rescanExports(savedDoc->fileName(), finder, newData) || hasNewInfo;
+                hasNewInfo = rescanExports(savedDoc->filePath().path(), finder, newData) || hasNewInfo;
             }
             continue;
         }
@@ -1453,7 +1453,7 @@ void ModelManagerInterface::updateCppQmlTypes(
         for (auto it = newDeclarations.begin(), end = newDeclarations.end(); it != end;) {
             for (auto docIt = it->begin(), endDocIt = it->end(); docIt != endDocIt;) {
                 const CPlusPlus::Document::Ptr &savedDoc = *docIt;
-                if (savedDoc->fileName() == fileName) {
+                if (savedDoc->filePath() == filePath) {
                     savedDoc->releaseSourceAndAST();
                     it->erase(docIt);
                     break;
@@ -1472,7 +1472,7 @@ void ModelManagerInterface::updateCppQmlTypes(
             doc->keepSourceAndAST(); // keep for later reparsing when dependent doc changes
         }
 
-        hasNewInfo = rescanExports(fileName, finder, newData) || hasNewInfo;
+        hasNewInfo = rescanExports(filePath.path(), finder, newData) || hasNewInfo;
         doc->releaseSourceAndAST();
     }
 
diff --git a/src/plugins/autotest/boost/boosttestparser.cpp b/src/plugins/autotest/boost/boosttestparser.cpp
index f49abe98505..791fdb5b026 100644
--- a/src/plugins/autotest/boost/boosttestparser.cpp
+++ b/src/plugins/autotest/boost/boosttestparser.cpp
@@ -57,14 +57,12 @@ static bool includesBoostTest(const CPlusPlus::Document::Ptr &doc,
             return true;
     }
 
-    for (const QString &include : snapshot.allIncludesForDocument(doc->fileName())) {
+    for (const QString &include : snapshot.allIncludesForDocument(doc->filePath().toString())) {
         if (boostTestHpp.match(include).hasMatch())
             return true;
     }
 
-    return CppParser::precompiledHeaderContains(snapshot,
-                                                Utils::FilePath::fromString(doc->fileName()),
-                                                boostTestHpp);
+    return CppParser::precompiledHeaderContains(snapshot, doc->filePath(), boostTestHpp);
 }
 
 static bool hasBoostTestMacros(const CPlusPlus::Document::Ptr &doc)
diff --git a/src/plugins/autotest/catch/catchtestparser.cpp b/src/plugins/autotest/catch/catchtestparser.cpp
index 122eb48c5ea..5c879474c3e 100644
--- a/src/plugins/autotest/catch/catchtestparser.cpp
+++ b/src/plugins/autotest/catch/catchtestparser.cpp
@@ -13,6 +13,8 @@
 
 #include <QRegularExpression>
 
+using namespace Utils;
+
 namespace Autotest {
 namespace Internal {
 
@@ -59,7 +61,7 @@ static bool includesCatchHeader(const CPlusPlus::Document::Ptr &doc,
         }
     }
 
-    for (const QString &include : snapshot.allIncludesForDocument(doc->fileName())) {
+    for (const QString &include : snapshot.allIncludesForDocument(doc->filePath().toString())) {
         for (const QString &catchHeader : catchHeaders) {
             if (include.endsWith(catchHeader))
                 return true;
@@ -67,9 +69,7 @@ static bool includesCatchHeader(const CPlusPlus::Document::Ptr &doc,
     }
 
     for (const QString &catchHeader : catchHeaders) {
-        if (CppParser::precompiledHeaderContains(snapshot,
-                                                 Utils::FilePath::fromString(doc->fileName()),
-                                                 catchHeader))
+        if (CppParser::precompiledHeaderContains(snapshot, doc->filePath(), catchHeader))
             return true;
     }
     return false;
@@ -99,7 +99,7 @@ bool CatchTestParser::processDocument(QFutureInterface<TestParseResultPtr> &futu
         return false;
 
     const CppEditor::CppModelManager *modelManager = CppEditor::CppModelManager::instance();
-    const QString &filePath = doc->fileName();
+    const QString &filePath = doc->filePath().toString();
     const QByteArray &fileContent = getFileContent(fileName);
 
     if (!hasCatchNames(doc)) {
diff --git a/src/plugins/autotest/gtest/gtestparser.cpp b/src/plugins/autotest/gtest/gtestparser.cpp
index d5eb7bfc09a..0f0e2aa3c0b 100644
--- a/src/plugins/autotest/gtest/gtestparser.cpp
+++ b/src/plugins/autotest/gtest/gtestparser.cpp
@@ -13,6 +13,8 @@
 #include <QRegularExpression>
 #include <QRegularExpressionMatch>
 
+using namespace Utils;
+
 namespace Autotest {
 namespace Internal {
 
@@ -45,14 +47,12 @@ static bool includesGTest(const CPlusPlus::Document::Ptr &doc,
             return true;
     }
 
-    for (const QString &include : snapshot.allIncludesForDocument(doc->fileName())) {
+    for (const QString &include : snapshot.allIncludesForDocument(doc->filePath().toString())) {
         if (include.endsWith(gtestH))
             return true;
     }
 
-    return CppParser::precompiledHeaderContains(snapshot,
-                                                Utils::FilePath::fromString(doc->fileName()),
-                                                gtestH);
+    return CppParser::precompiledHeaderContains(snapshot, doc->filePath(), gtestH);
 }
 
 static bool hasGTestNames(const CPlusPlus::Document::Ptr &document)
@@ -84,7 +84,7 @@ bool GTestParser::processDocument(QFutureInterface<TestParseResultPtr> &futureIn
             return false;
     }
 
-    const QString &filePath = doc->fileName();
+    const FilePath filePath = doc->filePath();
     const CppEditor::CppModelManager *modelManager = CppEditor::CppModelManager::instance();
     CPlusPlus::Document::Ptr document = m_cppSnapshot.preprocessedDocument(fileContent, fileName);
     document->check();
diff --git a/src/plugins/autotest/qtest/qttestparser.cpp b/src/plugins/autotest/qtest/qttestparser.cpp
index e5753a36a84..9bbb4d281d8 100644
--- a/src/plugins/autotest/qtest/qttestparser.cpp
+++ b/src/plugins/autotest/qtest/qttestparser.cpp
@@ -12,6 +12,8 @@
 
 #include <QRegularExpressionMatchIterator>
 
+using namespace Utils;
+
 namespace Autotest {
 namespace Internal {
 
@@ -51,7 +53,7 @@ static bool includesQtTest(const CPlusPlus::Document::Ptr &doc, const CPlusPlus:
         }
     }
 
-    const QSet<QString> allIncludes = snapshot.allIncludesForDocument(doc->fileName());
+    const QSet<QString> allIncludes = snapshot.allIncludesForDocument(doc->filePath().toString());
     for (const QString &include : allIncludes) {
         for (const QString &prefix : expectedHeaderPrefixes) {
         if (include.endsWith(QString("%1/qtest.h").arg(prefix)))
@@ -61,7 +63,7 @@ static bool includesQtTest(const CPlusPlus::Document::Ptr &doc, const CPlusPlus:
 
     for (const QString &prefix : expectedHeaderPrefixes) {
         if (CppParser::precompiledHeaderContains(snapshot,
-                                                 Utils::FilePath::fromString(doc->fileName()),
+                                                 doc->filePath(),
                                                  QString("%1/qtest.h").arg(prefix))) {
             return true;
         }
@@ -82,10 +84,10 @@ static bool qtTestLibDefined(const Utils::FilePath &fileName)
 }
 
 TestCases QtTestParser::testCases(const CppEditor::CppModelManager *modelManager,
-                                  const Utils::FilePath &fileName) const
+                                  const Utils::FilePath &filePath) const
 {
-    const QByteArray &fileContent = getFileContent(fileName);
-    CPlusPlus::Document::Ptr document = modelManager->document(fileName.toString());
+    const QByteArray &fileContent = getFileContent(filePath);
+    CPlusPlus::Document::Ptr document = modelManager->document(filePath);
     if (document.isNull())
         return {};
 
@@ -101,7 +103,7 @@ TestCases QtTestParser::testCases(const CppEditor::CppModelManager *modelManager
         }
     }
     // check if one has used a self-defined macro or QTest::qExec() directly
-    document = m_cppSnapshot.preprocessedDocument(fileContent, fileName);
+    document = m_cppSnapshot.preprocessedDocument(fileContent, filePath);
     document->check();
     CPlusPlus::AST *ast = document->translationUnit()->ast();
     TestAstVisitor astVisitor(document, m_cppSnapshot);
@@ -288,7 +290,7 @@ static QtTestCodeLocationList tagLocationsFor(const QtTestParseResult *func,
 
 static bool isQObject(const CPlusPlus::Document::Ptr &declaringDoc)
 {
-    const QString file = declaringDoc->fileName();
+    const FilePath file = declaringDoc->filePath();
     return (Utils::HostOsInfo::isMacHost() && file.endsWith("QtCore.framework/Headers/qobject.h"))
             || file.endsWith("QtCore/qobject.h")  || file.endsWith("kernel/qobject.h");
 }
@@ -337,8 +339,7 @@ std::optional<bool> QtTestParser::fillTestCaseData(
         const QString &testCaseName, const CPlusPlus::Document::Ptr &doc,
         TestCaseData &data) const
 {
-    const Utils::FilePath filePath = Utils::FilePath::fromString(doc->fileName());
-    const Utils::FilePaths &alternativeFiles = m_alternativeFiles.values(filePath);
+    const FilePaths &alternativeFiles = m_alternativeFiles.values(doc->filePath());
     CPlusPlus::Document::Ptr declaringDoc = declaringDocument(doc, m_cppSnapshot, testCaseName,
                                                               alternativeFiles,
                                                               &(data.line), &(data.column));
@@ -364,7 +365,7 @@ std::optional<bool> QtTestParser::fillTestCaseData(
     for (const Utils::FilePath &file : files)
         Utils::addToHash(&(data.dataTags), checkForDataTags(file));
 
-    data.fileName = Utils::FilePath::fromString(declaringDoc->fileName());
+    data.fileName = declaringDoc->filePath();
     data.valid = true;
     return std::optional<bool>();
 }
diff --git a/src/plugins/autotest/quick/quicktestparser.cpp b/src/plugins/autotest/quick/quicktestparser.cpp
index b133938abc2..594b2364a07 100644
--- a/src/plugins/autotest/quick/quicktestparser.cpp
+++ b/src/plugins/autotest/quick/quicktestparser.cpp
@@ -20,6 +20,7 @@
 #include <utils/qtcassert.h>
 
 using namespace QmlJS;
+using namespace Utils;
 
 namespace Autotest {
 namespace Internal {
@@ -59,7 +60,7 @@ static bool includesQtQuickTest(const CPlusPlus::Document::Ptr &doc,
         }
     }
 
-    for (const QString &include : snapshot.allIncludesForDocument(doc->fileName())) {
+    for (const QString &include : snapshot.allIncludesForDocument(doc->filePath().toString())) {
         for (const QString &prefix : expectedHeaderPrefixes) {
             if (include.endsWith(QString("%1/quicktest.h").arg(prefix)))
                 return true;
@@ -68,7 +69,7 @@ static bool includesQtQuickTest(const CPlusPlus::Document::Ptr &doc,
 
     for (const QString &prefix : expectedHeaderPrefixes) {
         if (CppParser::precompiledHeaderContains(snapshot,
-                                                 Utils::FilePath::fromString(doc->fileName()),
+                                                 doc->filePath(),
                                                  QString("%1/quicktest.h").arg(prefix))) {
             return true;
         }
@@ -101,7 +102,7 @@ static QString quickTestSrcDir(const CppEditor::CppModelManager *cppMM,
 QString QuickTestParser::quickTestName(const CPlusPlus::Document::Ptr &doc) const
 {
     const QList<CPlusPlus::Document::MacroUse> macros = doc->macroUses();
-    const Utils::FilePath filePath = Utils::FilePath::fromString(doc->fileName());
+    const Utils::FilePath filePath = doc->filePath();
 
     for (const CPlusPlus::Document::MacroUse &macro : macros) {
         if (!macro.isFunctionLike() || macro.arguments().isEmpty())
@@ -253,11 +254,11 @@ bool QuickTestParser::handleQtQuickTest(QFutureInterface<TestParseResultPtr> &fu
     if (quickTestName(document).isEmpty())
         return false;
 
-    QList<CppEditor::ProjectPart::ConstPtr> ppList = modelManager->projectPart(document->fileName());
+    QList<CppEditor::ProjectPart::ConstPtr> ppList = modelManager->projectPart(document->filePath());
     if (ppList.isEmpty()) // happens if shutting down while parsing
         return false;
-    const Utils::FilePath cppFileName = Utils::FilePath::fromString(document->fileName());
-    const Utils::FilePath proFile = Utils::FilePath::fromString(ppList.at(0)->projectFile);
+    const FilePath cppFileName = document->filePath();
+    const FilePath proFile = Utils::FilePath::fromString(ppList.at(0)->projectFile);
     m_mainCppFiles.insert(cppFileName, proFile);
     const Utils::FilePath srcDir = Utils::FilePath::fromString(
         quickTestSrcDir(modelManager, cppFileName));
diff --git a/src/plugins/autotest/testcodeparser.cpp b/src/plugins/autotest/testcodeparser.cpp
index f9c13045d88..8edfea8a262 100644
--- a/src/plugins/autotest/testcodeparser.cpp
+++ b/src/plugins/autotest/testcodeparser.cpp
@@ -161,7 +161,7 @@ void TestCodeParser::onDocumentUpdated(const Utils::FilePath &fileName, bool isQ
 
 void TestCodeParser::onCppDocumentUpdated(const CPlusPlus::Document::Ptr &document)
 {
-    onDocumentUpdated(Utils::FilePath::fromString(document->fileName()));
+    onDocumentUpdated(document->filePath());
 }
 
 void TestCodeParser::onQmlDocumentUpdated(const QmlJS::Document::Ptr &document)
diff --git a/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp b/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
index 46fb37ac456..d4c2e94bed1 100644
--- a/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
+++ b/src/plugins/clangcodemodel/clangeditordocumentprocessor.cpp
@@ -41,7 +41,7 @@ ClangEditorDocumentProcessor::ClangEditorDocumentProcessor(TextEditor::TextDocum
     connect(static_cast<CppEditor::BuiltinEditorDocumentParser *>(parser().data()),
             &CppEditor::BuiltinEditorDocumentParser::finished,
             this, [this] {
-        emit parserConfigChanged(Utils::FilePath::fromString(filePath()), parserConfig());
+        emit parserConfigChanged(filePath(), parserConfig());
     });
     setSemanticHighlightingChecker([this] {
         return !ClangModelManagerSupport::clientForFile(m_document.filePath());
@@ -84,7 +84,7 @@ void ClangEditorDocumentProcessor::setParserConfig(
         const CppEditor::BaseEditorDocumentParser::Configuration &config)
 {
     CppEditor::BuiltinEditorDocumentProcessor::setParserConfig(config);
-    emit parserConfigChanged(Utils::FilePath::fromString(filePath()), config);
+    emit parserConfigChanged(filePath(), config);
 }
 
 CppEditor::BaseEditorDocumentParser::Configuration ClangEditorDocumentProcessor::parserConfig()
diff --git a/src/plugins/classview/classviewmanager.cpp b/src/plugins/classview/classviewmanager.cpp
index ee1f89c7c75..1e0cf89f719 100644
--- a/src/plugins/classview/classviewmanager.cpp
+++ b/src/plugins/classview/classviewmanager.cpp
@@ -275,7 +275,7 @@ void Manager::initialize()
         if (doc.data() == nullptr)
             return;
 
-        d->m_awaitingDocuments.insert(FilePath::fromString(doc->fileName()));
+        d->m_awaitingDocuments.insert(doc->filePath());
         d->m_timer.start(400); // Accumulate multiple requests into one, restarts the timer
     });
 
diff --git a/src/plugins/classview/classviewparser.cpp b/src/plugins/classview/classviewparser.cpp
index cbc90bf4fe9..821ec947992 100644
--- a/src/plugins/classview/classviewparser.cpp
+++ b/src/plugins/classview/classviewparser.cpp
@@ -215,7 +215,7 @@ ParserTreeItem::ConstPtr Parser::getParseDocumentTree(const CPlusPlus::Document:
     if (doc.isNull())
         return ParserTreeItem::ConstPtr();
 
-    const FilePath fileName = FilePath::fromString(doc->fileName());
+    const FilePath fileName = doc->filePath();
 
     ParserTreeItem::ConstPtr itemPtr = ParserTreeItem::parseDocument(doc);
 
@@ -235,8 +235,7 @@ ParserTreeItem::ConstPtr Parser::getCachedOrParseDocumentTree(const CPlusPlus::D
     if (doc.isNull())
         return ParserTreeItem::ConstPtr();
 
-    const QString &fileName = doc->fileName();
-    const auto it = d->m_documentCache.constFind(FilePath::fromString(fileName));
+    const auto it = d->m_documentCache.constFind(doc->filePath());
     if (it != d->m_documentCache.constEnd() && !it.value().tree.isNull()
             && it.value().treeRevision == doc->revision()) {
         return it.value().tree;
diff --git a/src/plugins/cppeditor/baseeditordocumentprocessor.cpp b/src/plugins/cppeditor/baseeditordocumentprocessor.cpp
index 97efb1c2584..252f0a49928 100644
--- a/src/plugins/cppeditor/baseeditordocumentprocessor.cpp
+++ b/src/plugins/cppeditor/baseeditordocumentprocessor.cpp
@@ -22,7 +22,7 @@ namespace CppEditor {
 */
 
 BaseEditorDocumentProcessor::BaseEditorDocumentProcessor(QTextDocument *textDocument,
-                                                         const QString &filePath)
+                                                         const Utils::FilePath &filePath)
     : m_filePath(filePath),
       m_textDocument(textDocument)
 {
diff --git a/src/plugins/cppeditor/baseeditordocumentprocessor.h b/src/plugins/cppeditor/baseeditordocumentprocessor.h
index d49efd095fa..9461876f6bb 100644
--- a/src/plugins/cppeditor/baseeditordocumentprocessor.h
+++ b/src/plugins/cppeditor/baseeditordocumentprocessor.h
@@ -10,6 +10,7 @@
 #include "cpptoolsreuse.h"
 
 #include <coreplugin/helpitem.h>
+
 #include <texteditor/codeassist/assistinterface.h>
 #include <texteditor/quickfix.h>
 #include <texteditor/texteditor.h>
@@ -18,7 +19,6 @@
 #include <cplusplus/CppDocument.h>
 
 #include <QTextEdit>
-
 #include <QVariant>
 
 #include <functional>
@@ -45,7 +45,7 @@ class CPPEDITOR_EXPORT BaseEditorDocumentProcessor : public QObject
     Q_OBJECT
 
 public:
-    BaseEditorDocumentProcessor(QTextDocument *textDocument, const QString &filePath);
+    BaseEditorDocumentProcessor(QTextDocument *textDocument, const Utils::FilePath &filePath);
     ~BaseEditorDocumentProcessor() override;
 
     void run(bool projectsUpdated = false);
@@ -65,7 +65,7 @@ public:
 
     virtual QFuture<CursorInfo> cursorInfo(const CursorInfoParams &params) = 0;
 
-    QString filePath() const { return m_filePath; }
+    const Utils::FilePath &filePath() const { return m_filePath; }
 
 signals:
     // Signal interface to implement
@@ -94,7 +94,7 @@ private:
     virtual void runImpl(const BaseEditorDocumentParser::UpdateParams &updateParams) = 0;
 
 private:
-    QString m_filePath;
+    Utils::FilePath m_filePath;
     QTextDocument *m_textDocument;
 };
 
diff --git a/src/plugins/cppeditor/builtincursorinfo.cpp b/src/plugins/cppeditor/builtincursorinfo.cpp
index a0190a3b13c..870c9addbe5 100644
--- a/src/plugins/cppeditor/builtincursorinfo.cpp
+++ b/src/plugins/cppeditor/builtincursorinfo.cpp
@@ -270,7 +270,7 @@ bool handleMacroCase(const Document::Ptr document,
     const int length = macro->nameToQString().size();
 
     // Macro definition
-    if (macro->fileName() == document->fileName())
+    if (macro->fileName() == document->filePath().pathView())
         ranges->append(toRange(textCursor, macro->utf16CharOffset(), length));
 
     // Other macro uses
diff --git a/src/plugins/cppeditor/builtineditordocumentparser.cpp b/src/plugins/cppeditor/builtineditordocumentparser.cpp
index 7d3a2430e84..221b7d70c87 100644
--- a/src/plugins/cppeditor/builtineditordocumentparser.cpp
+++ b/src/plugins/cppeditor/builtineditordocumentparser.cpp
@@ -137,15 +137,15 @@ void BuiltinEditorDocumentParser::updateImpl(const QFutureInterface<void> &futur
         // Remove changed files from the snapshot
         QSet<Utils::FilePath> toRemove;
         for (const Document::Ptr &doc : std::as_const(state.snapshot)) {
-            const Utils::FilePath fileName = Utils::FilePath::fromString(doc->fileName());
-            if (workingCopy.contains(fileName)) {
-                if (workingCopy.get(fileName).second != doc->editorRevision())
-                    addFileAndDependencies(&state.snapshot, &toRemove, fileName);
+            const Utils::FilePath filePath = doc->filePath();
+            if (workingCopy.contains(filePath)) {
+                if (workingCopy.get(filePath).second != doc->editorRevision())
+                    addFileAndDependencies(&state.snapshot, &toRemove, filePath);
                 continue;
             }
-            Document::Ptr otherDoc = globalSnapshot.document(fileName);
+            Document::Ptr otherDoc = globalSnapshot.document(filePath);
             if (!otherDoc.isNull() && otherDoc->revision() != doc->revision())
-                addFileAndDependencies(&state.snapshot, &toRemove, fileName);
+                addFileAndDependencies(&state.snapshot, &toRemove, filePath);
         }
 
         if (!toRemove.isEmpty()) {
@@ -165,9 +165,8 @@ void BuiltinEditorDocumentParser::updateImpl(const QFutureInterface<void> &futur
         state.snapshot.remove(filePath());
 
         Internal::CppSourceProcessor sourceProcessor(state.snapshot, [&](const Document::Ptr &doc) {
-            const QString fileName = doc->fileName();
-            const bool isInEditor = fileName == filePath();
-            Document::Ptr otherDoc = modelManager->document(fileName);
+            const bool isInEditor = doc->filePath().toString() == filePath();
+            Document::Ptr otherDoc = modelManager->document(doc->filePath());
             unsigned newRev = otherDoc.isNull() ? 1U : otherDoc->revision() + 1;
             if (isInEditor)
                 newRev = qMax(rev + 1, newRev);
diff --git a/src/plugins/cppeditor/builtineditordocumentprocessor.cpp b/src/plugins/cppeditor/builtineditordocumentprocessor.cpp
index 58947dcb634..fa74f71e6c4 100644
--- a/src/plugins/cppeditor/builtineditordocumentprocessor.cpp
+++ b/src/plugins/cppeditor/builtineditordocumentprocessor.cpp
@@ -136,7 +136,7 @@ QList<TextEditor::BlockRange> toTextEditorBlocks(
 } // anonymous namespace
 
 BuiltinEditorDocumentProcessor::BuiltinEditorDocumentProcessor(TextEditor::TextDocument *document)
-    : BaseEditorDocumentProcessor(document->document(), document->filePath().toString())
+    : BaseEditorDocumentProcessor(document->document(), document->filePath())
     , m_parser(new BuiltinEditorDocumentParser(document->filePath().toString(),
                                                indexerFileSizeLimitInMb()))
     , m_codeWarningsUpdated(false)
@@ -241,13 +241,13 @@ void BuiltinEditorDocumentProcessor::onParserFinished(CPlusPlus::Document::Ptr d
     if (document.isNull())
         return;
 
-    if (document->fileName() != filePath())
+    if (document->filePath() != filePath())
         return; // some other document got updated
 
     if (document->editorRevision() != revision())
         return; // outdated content, wait for a new document to be parsed
 
-    qCDebug(log) << "document parsed" << document->fileName() << document->editorRevision();
+    qCDebug(log) << "document parsed" << document->filePath() << document->editorRevision();
 
     // Emit ifdefed out blocks
     const auto ifdefoutBlocks = toTextEditorBlocks(document->skippedBlocks());
@@ -261,14 +261,14 @@ void BuiltinEditorDocumentProcessor::onParserFinished(CPlusPlus::Document::Ptr d
 
     m_documentSnapshot = snapshot;
     const auto source = createSemanticInfoSource(false);
-    QTC_CHECK(source.snapshot.contains(document->fileName()));
+    QTC_CHECK(source.snapshot.contains(document->filePath()));
     m_semanticInfoUpdater.updateDetached(source);
 }
 
 void BuiltinEditorDocumentProcessor::onSemanticInfoUpdated(const SemanticInfo semanticInfo)
 {
     qCDebug(log) << "semantic info updated"
-                 << semanticInfo.doc->fileName() << semanticInfo.revision << semanticInfo.complete;
+                 << semanticInfo.doc->filePath() << semanticInfo.revision << semanticInfo.complete;
 
     emit semanticInfoUpdated(semanticInfo);
 
@@ -283,7 +283,7 @@ void BuiltinEditorDocumentProcessor::onCodeWarningsUpdated(
     if (document.isNull())
         return;
 
-    if (document->fileName() != filePath())
+    if (document->filePath() != filePath())
         return; // some other document got updated
 
     if (document->editorRevision() != revision())
@@ -302,10 +302,9 @@ void BuiltinEditorDocumentProcessor::onCodeWarningsUpdated(
 SemanticInfo::Source BuiltinEditorDocumentProcessor::createSemanticInfoSource(bool force) const
 {
     const WorkingCopy workingCopy = CppModelManager::instance()->workingCopy();
-    const QString path = filePath();
-    return SemanticInfo::Source(path,
-                                workingCopy.source(path),
-                                workingCopy.revision(path),
+    return SemanticInfo::Source(filePath().toString(),
+                                workingCopy.source(filePath()),
+                                workingCopy.revision(filePath()),
                                 m_documentSnapshot,
                                 force);
 }
diff --git a/src/plugins/cppeditor/builtinindexingsupport.cpp b/src/plugins/cppeditor/builtinindexingsupport.cpp
index 81d8b11c2c5..474c410e147 100644
--- a/src/plugins/cppeditor/builtinindexingsupport.cpp
+++ b/src/plugins/cppeditor/builtinindexingsupport.cpp
@@ -71,7 +71,7 @@ public:
     void process(const CPlusPlus::Document::Ptr document)
     {
         using namespace CPlusPlus;
-        const QString fileName = document->fileName();
+        const QString fileName = document->filePath().toString();
 
         const QList<Document::DiagnosticMessage> messages = document->diagnosticMessages();
         for (const Document::DiagnosticMessage &message : messages) {
@@ -272,7 +272,7 @@ public:
                 future.waitForResume();
             if (future.isCanceled())
                 break;
-            if (m_fileNames.isEmpty() || m_fileNames.contains(it.value()->fileName())) {
+            if (m_fileNames.isEmpty() || m_fileNames.contains(it.value()->filePath().path())) {
                 QVector<Core::SearchResultItem> resultItems;
                 auto filter = [&](const IndexItem::Ptr &info) -> IndexItem::VisitorResult {
                     if (matcher.match(info->symbolName()).hasMatch()) {
diff --git a/src/plugins/cppeditor/cppchecksymbols.cpp b/src/plugins/cppeditor/cppchecksymbols.cpp
index 1621f6ae51f..c0ca4020701 100644
--- a/src/plugins/cppeditor/cppchecksymbols.cpp
+++ b/src/plugins/cppeditor/cppchecksymbols.cpp
@@ -312,7 +312,7 @@ void CheckSymbols::run()
 {
     CollectSymbols collectTypes(_doc, _context.snapshot());
 
-    _fileName = _doc->fileName();
+    _filePath = _doc->filePath();
     _potentialTypes = collectTypes.types();
     _potentialFields = collectTypes.fields();
     _potentialFunctions = collectTypes.functions();
@@ -334,7 +334,7 @@ void CheckSymbols::run()
 
 bool CheckSymbols::warning(unsigned line, unsigned column, const QString &text, unsigned length)
 {
-    Document::DiagnosticMessage m(Document::DiagnosticMessage::Warning, _fileName, line, column, text, length);
+    Document::DiagnosticMessage m(Document::DiagnosticMessage::Warning, _filePath, line, column, text, length);
     _diagMsgs.append(m);
     return false;
 }
diff --git a/src/plugins/cppeditor/cppchecksymbols.h b/src/plugins/cppeditor/cppchecksymbols.h
index 044dc76f4ca..c2416081ffa 100644
--- a/src/plugins/cppeditor/cppchecksymbols.h
+++ b/src/plugins/cppeditor/cppchecksymbols.h
@@ -170,7 +170,7 @@ private:
     CPlusPlus::Document::Ptr _doc;
     CPlusPlus::LookupContext _context;
     CPlusPlus::TypeOfExpression typeOfExpression;
-    QString _fileName;
+    Utils::FilePath _filePath;
     QSet<QByteArray> _potentialTypes;
     QSet<QByteArray> _potentialFields;
     QSet<QByteArray> _potentialFunctions;
diff --git a/src/plugins/cppeditor/cppcodegen_test.cpp b/src/plugins/cppeditor/cppcodegen_test.cpp
index 22791b08995..6b7e1b3cc58 100644
--- a/src/plugins/cppeditor/cppcodegen_test.cpp
+++ b/src/plugins/cppeditor/cppcodegen_test.cpp
@@ -18,6 +18,7 @@
     tests the InsertionPointLocator.
  */
 using namespace CPlusPlus;
+using namespace Utils;
 
 using CppEditor::Tests::TemporaryDir;
 
@@ -42,10 +43,10 @@ Document::Ptr createDocumentAndFile(TemporaryDir *temporaryDir,
                                     int expectedGlobalSymbolCount)
 {
     QTC_ASSERT(temporaryDir, return Document::Ptr());
-    const QString absoluteFilePath = temporaryDir->createFile(relativeFilePath, text);
+    const FilePath absoluteFilePath = temporaryDir->createFile(relativeFilePath, text);
     QTC_ASSERT(!absoluteFilePath.isEmpty(), return Document::Ptr());
 
-    return createDocument(absoluteFilePath, text, expectedGlobalSymbolCount);
+    return createDocument(absoluteFilePath.toString(), text, expectedGlobalSymbolCount);
 }
 
 } // anonymous namespace
@@ -73,7 +74,7 @@ void CodegenTest::testPublicInEmptyClass()
     CppRefactoringChanges changes(snapshot);
     InsertionPointLocator find(changes);
     InsertionLocation loc = find.methodDeclarationInClass(
-                doc->fileName(),
+                doc->filePath(),
                 foo,
                 InsertionPointLocator::Public);
     QVERIFY(loc.isValid());
@@ -107,7 +108,7 @@ void CodegenTest::testPublicInNonemptyClass()
     CppRefactoringChanges changes(snapshot);
     InsertionPointLocator find(changes);
     InsertionLocation loc = find.methodDeclarationInClass(
-                doc->fileName(),
+                doc->filePath(),
                 foo,
                 InsertionPointLocator::Public);
     QVERIFY(loc.isValid());
@@ -141,7 +142,7 @@ void CodegenTest::testPublicBeforeProtected()
     CppRefactoringChanges changes(snapshot);
     InsertionPointLocator find(changes);
     InsertionLocation loc = find.methodDeclarationInClass(
-                doc->fileName(),
+                doc->filePath(),
                 foo,
                 InsertionPointLocator::Public);
     QVERIFY(loc.isValid());
@@ -176,7 +177,7 @@ void CodegenTest::testPrivateAfterProtected()
     CppRefactoringChanges changes(snapshot);
     InsertionPointLocator find(changes);
     InsertionLocation loc = find.methodDeclarationInClass(
-                doc->fileName(),
+                doc->filePath(),
                 foo,
                 InsertionPointLocator::Private);
     QVERIFY(loc.isValid());
@@ -211,7 +212,7 @@ void CodegenTest::testProtectedInNonemptyClass()
     CppRefactoringChanges changes(snapshot);
     InsertionPointLocator find(changes);
     InsertionLocation loc = find.methodDeclarationInClass(
-                doc->fileName(),
+                doc->filePath(),
                 foo,
                 InsertionPointLocator::Protected);
     QVERIFY(loc.isValid());
@@ -246,7 +247,7 @@ void CodegenTest::testProtectedBetweenPublicAndPrivate()
     CppRefactoringChanges changes(snapshot);
     InsertionPointLocator find(changes);
     InsertionLocation loc = find.methodDeclarationInClass(
-                doc->fileName(),
+                doc->filePath(),
                 foo,
                 InsertionPointLocator::Protected);
     QVERIFY(loc.isValid());
@@ -302,7 +303,7 @@ void CodegenTest::testQtdesignerIntegration()
     CppRefactoringChanges changes(snapshot);
     InsertionPointLocator find(changes);
     InsertionLocation loc = find.methodDeclarationInClass(
-                doc->fileName(),
+                doc->filePath(),
                 foo,
                 InsertionPointLocator::PrivateSlot);
     QVERIFY(loc.isValid());
@@ -351,7 +352,7 @@ void CodegenTest::testDefinitionEmptyClass()
     QList<InsertionLocation> locList = find.methodDefinition(decl);
     QVERIFY(locList.size() == 1);
     InsertionLocation loc = locList.first();
-    QCOMPARE(loc.fileName(), sourceDocument->fileName());
+    QCOMPARE(loc.fileName(), sourceDocument->filePath().toString());
     QCOMPARE(loc.prefix(), QLatin1String("\n\n"));
     QCOMPARE(loc.suffix(), QString());
     QCOMPARE(loc.line(), 3);
@@ -387,7 +388,7 @@ void CodegenTest::testDefinitionFirstMember()
     Document::Ptr sourceDocument = createDocumentAndFile(&temporaryDir, "file.cpp", sourceText, 3);
     QVERIFY(sourceDocument);
     sourceDocument->addIncludeFile(Document::Include(QLatin1String("file.h"),
-                                                     headerDocument->fileName(), 1,
+                                                     headerDocument->filePath().toString(), 1,
                                                      Client::IncludeLocal));
 
     Snapshot snapshot;
@@ -409,7 +410,7 @@ void CodegenTest::testDefinitionFirstMember()
     QList<InsertionLocation> locList = find.methodDefinition(decl);
     QVERIFY(locList.size() == 1);
     InsertionLocation loc = locList.first();
-    QCOMPARE(loc.fileName(), sourceDocument->fileName());
+    QCOMPARE(loc.fileName(), sourceDocument->filePath().toString());
     QCOMPARE(loc.line(), 4);
     QCOMPARE(loc.column(), 1);
     QCOMPARE(loc.suffix(), QLatin1String("\n\n"));
@@ -446,7 +447,7 @@ void CodegenTest::testDefinitionLastMember()
     Document::Ptr sourceDocument = createDocumentAndFile(&temporaryDir, "file.cpp", sourceText, 3);
     QVERIFY(sourceDocument);
     sourceDocument->addIncludeFile(Document::Include(QLatin1String("file.h"),
-                                                     headerDocument->fileName(), 1,
+                                                     headerDocument->filePath().toString(), 1,
                                                      Client::IncludeLocal));
 
     Snapshot snapshot;
@@ -468,7 +469,7 @@ void CodegenTest::testDefinitionLastMember()
     QList<InsertionLocation> locList = find.methodDefinition(decl);
     QVERIFY(locList.size() == 1);
     InsertionLocation loc = locList.first();
-    QCOMPARE(loc.fileName(), sourceDocument->fileName());
+    QCOMPARE(loc.fileName(), sourceDocument->filePath().toString());
     QCOMPARE(loc.line(), 7);
     QCOMPARE(loc.column(), 2);
     QCOMPARE(loc.prefix(), QLatin1String("\n\n"));
@@ -512,7 +513,7 @@ void CodegenTest::testDefinitionMiddleMember()
     Document::Ptr sourceDocument = createDocumentAndFile(&temporaryDir, "file.cpp", sourceText, 4);
     QVERIFY(sourceDocument);
     sourceDocument->addIncludeFile(Document::Include(QLatin1String("file.h"),
-                                                     headerDocument->fileName(), 1,
+                                                     headerDocument->filePath().toString(), 1,
                                                      Client::IncludeLocal));
 
     Snapshot snapshot;
@@ -534,7 +535,7 @@ void CodegenTest::testDefinitionMiddleMember()
     QList<InsertionLocation> locList = find.methodDefinition(decl);
     QVERIFY(locList.size() == 1);
     InsertionLocation loc = locList.first();
-    QCOMPARE(loc.fileName(), sourceDocument->fileName());
+    QCOMPARE(loc.fileName(), sourceDocument->filePath().toString());
     QCOMPARE(loc.line(), 7);
     QCOMPARE(loc.column(), 2);
     QCOMPARE(loc.prefix(), QLatin1String("\n\n"));
@@ -572,7 +573,7 @@ void CodegenTest::testDefinitionMiddleMemberSurroundedByUndefined()
     Document::Ptr sourceDocument = createDocumentAndFile(&temporaryDir, "file.cpp", sourceText, 3);
     QVERIFY(sourceDocument);
     sourceDocument->addIncludeFile(Document::Include(QLatin1String("file.h"),
-                                                     headerDocument->fileName(), 1,
+                                                     headerDocument->filePath().toString(), 1,
                                                      Client::IncludeLocal));
 
     Snapshot snapshot;
@@ -594,7 +595,7 @@ void CodegenTest::testDefinitionMiddleMemberSurroundedByUndefined()
     QList<InsertionLocation> locList = find.methodDefinition(decl);
     QVERIFY(locList.size() == 1);
     InsertionLocation loc = locList.first();
-    QCOMPARE(loc.fileName(), sourceDocument->fileName());
+    QCOMPARE(loc.fileName(), sourceDocument->filePath().toString());
     QCOMPARE(loc.line(), 4);
     QCOMPARE(loc.column(), 1);
     QCOMPARE(loc.prefix(), QString());
@@ -635,7 +636,7 @@ void CodegenTest::testDefinitionMemberSpecificFile()
     Document::Ptr sourceDocument = createDocumentAndFile(&temporaryDir, "file.cpp", sourceText, 3);
     QVERIFY(sourceDocument);
     sourceDocument->addIncludeFile(Document::Include(QLatin1String("file.h"),
-                                                     headerDocument->fileName(), 1,
+                                                     headerDocument->filePath().toString(), 1,
                                                      Client::IncludeLocal));
 
     Snapshot snapshot;
@@ -654,10 +655,11 @@ void CodegenTest::testDefinitionMemberSpecificFile()
 
     CppRefactoringChanges changes(snapshot);
     InsertionPointLocator find(changes);
-    QList<InsertionLocation> locList = find.methodDefinition(decl, true, sourceDocument->fileName());
+    QList<InsertionLocation> locList =
+            find.methodDefinition(decl, true, sourceDocument->filePath().toString());
     QVERIFY(locList.size() == 1);
     InsertionLocation loc = locList.first();
-    QCOMPARE(loc.fileName(), sourceDocument->fileName());
+    QCOMPARE(loc.fileName(), sourceDocument->filePath().toString());
     QCOMPARE(loc.line(), 7);
     QCOMPARE(loc.column(), 2);
     QCOMPARE(loc.prefix(), QLatin1String("\n\n"));
diff --git a/src/plugins/cppeditor/cppcodemodelinspectordialog.cpp b/src/plugins/cppeditor/cppcodemodelinspectordialog.cpp
index 0b5006e6bff..176bd9f4fcc 100644
--- a/src/plugins/cppeditor/cppcodemodelinspectordialog.cpp
+++ b/src/plugins/cppeditor/cppcodemodelinspectordialog.cpp
@@ -33,6 +33,8 @@
 #include <numeric>
 
 using namespace CPlusPlus;
+using namespace Utils;
+
 namespace CMI = CppEditor::CppCodeModelInspector;
 
 namespace {
@@ -48,11 +50,11 @@ TextEditor::BaseTextEditor *currentEditor()
     return qobject_cast<TextEditor::BaseTextEditor*>(Core::EditorManager::currentEditor());
 }
 
-QString fileInCurrentEditor()
+Utils::FilePath fileInCurrentEditor()
 {
     if (TextEditor::BaseTextEditor *editor = currentEditor())
-        return editor->document()->filePath().toString();
-    return QString();
+        return editor->document()->filePath();
+    return {};
 }
 
 QSizePolicy sizePolicyWithStretchFactor(int stretchFactor)
@@ -435,7 +437,7 @@ public:
     void configure(const Snapshot &snapshot);
     void setGlobalSnapshot(const Snapshot &snapshot);
 
-    QModelIndex indexForDocument(const QString &filePath);
+    QModelIndex indexForDocument(const Utils::FilePath &filePath);
 
     enum Columns { SymbolCountColumn, SharedColumn, FilePathColumn, ColumnCount };
 
@@ -465,11 +467,11 @@ void SnapshotModel::setGlobalSnapshot(const Snapshot &snapshot)
     m_globalSnapshot = snapshot;
 }
 
-QModelIndex SnapshotModel::indexForDocument(const QString &filePath)
+QModelIndex SnapshotModel::indexForDocument(const FilePath &filePath)
 {
     for (int i = 0, total = m_documents.size(); i < total; ++i) {
         const Document::Ptr document = m_documents.at(i);
-        if (document->fileName() == filePath)
+        if (document->filePath() == filePath)
             return index(i, FilePathColumn);
     }
     return {};
@@ -493,12 +495,12 @@ QVariant SnapshotModel::data(const QModelIndex &index, int role) const
         if (column == SymbolCountColumn) {
             return document->control()->symbolCount();
         } else if (column == SharedColumn) {
-            Document::Ptr globalDocument = m_globalSnapshot.document(document->fileName());
+            Document::Ptr globalDocument = m_globalSnapshot.document(document->filePath());
             const bool isShared
                 = globalDocument && globalDocument->fingerprint() == document->fingerprint();
             return CMI::Utils::toString(isShared);
         } else if (column == FilePathColumn) {
-            return QDir::toNativeSeparators(document->fileName());
+            return document->filePath().toUserOutput();
         }
     }
     return QVariant();
@@ -1200,7 +1202,7 @@ public:
     WorkingCopyModel(QObject *parent);
 
     void configure(const WorkingCopy &workingCopy);
-    QModelIndex indexForFile(const QString &filePath);
+    QModelIndex indexForFile(const Utils::FilePath &filePath);
 
     enum Columns { RevisionColumn, FilePathColumn, ColumnCount };
 
@@ -1211,11 +1213,11 @@ public:
 
 private:
     struct WorkingCopyEntry {
-        WorkingCopyEntry(const QString &filePath, const QByteArray &source, unsigned revision)
+        WorkingCopyEntry(const Utils::FilePath &filePath, const QByteArray &source, unsigned revision)
             : filePath(filePath), source(source), revision(revision)
         {}
 
-        QString filePath;
+        Utils::FilePath filePath;
         QByteArray source;
         unsigned revision;
     };
@@ -1232,14 +1234,13 @@ void WorkingCopyModel::configure(const WorkingCopy &workingCopy)
     emit layoutAboutToBeChanged();
     m_workingCopyList.clear();
     const WorkingCopy::Table &elements = workingCopy.elements();
-    for (auto it = elements.cbegin(), end = elements.cend(); it != end; ++it) {
-        m_workingCopyList << WorkingCopyEntry(it.key().toString(), it.value().first,
-                                              it.value().second);
-    }
+    for (auto it = elements.cbegin(), end = elements.cend(); it != end; ++it)
+        m_workingCopyList << WorkingCopyEntry(it.key(), it.value().first, it.value().second);
+
     emit layoutChanged();
 }
 
-QModelIndex WorkingCopyModel::indexForFile(const QString &filePath)
+QModelIndex WorkingCopyModel::indexForFile(const Utils::FilePath &filePath)
 {
     for (int i = 0, total = m_workingCopyList.size(); i < total; ++i) {
         const WorkingCopyEntry entry = m_workingCopyList.at(i);
@@ -1267,7 +1268,7 @@ QVariant WorkingCopyModel::data(const QModelIndex &index, int role) const
         if (column == RevisionColumn)
             return m_workingCopyList.at(row).revision;
         else if (column == FilePathColumn)
-            return m_workingCopyList.at(row).filePath;
+            return m_workingCopyList.at(row).filePath.toString();
     } else if (role == Qt::UserRole) {
         return m_workingCopyList.at(row).source;
     }
@@ -1659,14 +1660,14 @@ void CppCodeModelInspectorDialog::updateDocumentData(const Document::Ptr &docume
 
     // General
     const KeyValueModel::Table table = {
-        {QString::fromLatin1("File Path"), QDir::toNativeSeparators(document->fileName())},
+        {QString::fromLatin1("File Path"), document->filePath().toUserOutput()},
         {QString::fromLatin1("Last Modified"), CMI::Utils::toString(document->lastModified())},
         {QString::fromLatin1("Revision"), CMI::Utils::toString(document->revision())},
         {QString::fromLatin1("Editor Revision"), CMI::Utils::toString(document->editorRevision())},
         {QString::fromLatin1("Check Mode"), CMI::Utils::toString(document->checkMode())},
         {QString::fromLatin1("Tokenized"), CMI::Utils::toString(document->isTokenized())},
         {QString::fromLatin1("Parsed"), CMI::Utils::toString(document->isParsed())},
-        {QString::fromLatin1("Project Parts"), CMI::Utils::partsForFile(document->fileName())}
+        {QString::fromLatin1("Project Parts"), CMI::Utils::partsForFile(document->filePath())}
     };
     m_docGenericInfoModel->configure(table);
     resizeColumns<KeyValueModel>(m_ui->docGeneralView);
diff --git a/src/plugins/cppeditor/cppcodemodelinspectordumper.cpp b/src/plugins/cppeditor/cppcodemodelinspectordumper.cpp
index b82c2a03e11..4341c746082 100644
--- a/src/plugins/cppeditor/cppcodemodelinspectordumper.cpp
+++ b/src/plugins/cppeditor/cppcodemodelinspectordumper.cpp
@@ -384,10 +384,10 @@ QString Utils::toString(const ProjectExplorer::Abi &abi)
     return QString("??");
 }
 
-QString Utils::partsForFile(const QString &fileName)
+QString Utils::partsForFile(const ::Utils::FilePath &filePath)
 {
     const QList<ProjectPart::ConstPtr> parts
-        = CppModelManager::instance()->projectPart(fileName);
+        = CppModelManager::instance()->projectPart(filePath);
     QString result;
     for (const ProjectPart::ConstPtr &part : parts)
         result += part->displayName + QLatin1Char(',');
@@ -580,7 +580,7 @@ void Dumper::dumpSnapshot(const CPlusPlus::Snapshot &snapshot, const QString &ti
         QList<CPlusPlus::Document::Ptr> globallyShared;
         QList<CPlusPlus::Document::Ptr> notGloballyShared;
         for (const CPlusPlus::Document::Ptr &document : documents) {
-            CPlusPlus::Document::Ptr globalDocument = m_globalSnapshot.document(document->fileName());
+            CPlusPlus::Document::Ptr globalDocument = m_globalSnapshot.document(document->filePath());
             if (globalDocument && globalDocument->fingerprint() == document->fingerprint())
                 globallyShared.append(document);
             else
@@ -641,18 +641,18 @@ void Dumper::dumpDocuments(const QList<CPlusPlus::Document::Ptr> &documents, boo
     const QByteArray i4 = indent(4);
     for (const CPlusPlus::Document::Ptr &document : documents) {
         if (skipDetails) {
-            m_out << i2 << "\"" << document->fileName() << "\"\n";
+            m_out << i2 << "\"" << document->filePath() << "\"\n";
             continue;
         }
 
-        m_out << i2 << "Document \"" << document->fileName() << "\"{{{3\n";
+        m_out << i2 << "Document \"" << document->filePath() << "\"{{{3\n";
         m_out << i3 << "Last Modified  : " << Utils::toString(document->lastModified()) << "\n";
         m_out << i3 << "Revision       : " << Utils::toString(document->revision()) << "\n";
         m_out << i3 << "Editor Revision: " << Utils::toString(document->editorRevision()) << "\n";
         m_out << i3 << "Check Mode     : " << Utils::toString(document->checkMode()) << "\n";
         m_out << i3 << "Tokenized      : " << Utils::toString(document->isTokenized()) << "\n";
         m_out << i3 << "Parsed         : " << Utils::toString(document->isParsed()) << "\n";
-        m_out << i3 << "Project Parts  : " << Utils::partsForFile(document->fileName()) << "\n";
+        m_out << i3 << "Project Parts  : " << Utils::partsForFile(document->filePath()) << "\n";
 
         const QList<CPlusPlus::Document::Include> includes = document->unresolvedIncludes()
                 + document->resolvedIncludes();
diff --git a/src/plugins/cppeditor/cppcodemodelinspectordumper.h b/src/plugins/cppeditor/cppcodemodelinspectordumper.h
index 872c868fee0..03b3c7c703b 100644
--- a/src/plugins/cppeditor/cppcodemodelinspectordumper.h
+++ b/src/plugins/cppeditor/cppcodemodelinspectordumper.h
@@ -33,7 +33,7 @@ struct Utils
     static QString toString(ProjectFile::Kind kind);
     static QString toString(CPlusPlus::Kind kind);
     static QString toString(const ProjectExplorer::Abi &abi);
-    static QString partsForFile(const QString &fileName);
+    static QString partsForFile(const ::Utils::FilePath &filePath);
     static QString unresolvedFileNameWithDelimiters(const CPlusPlus::Document::Include &include);
     static QString pathListToString(const QStringList &pathList);
     static QString pathListToString(const ProjectExplorer::HeaderPaths &pathList);
diff --git a/src/plugins/cppeditor/cppcodestylesettingspage.cpp b/src/plugins/cppeditor/cppcodestylesettingspage.cpp
index 37cdc81c7f6..7f2f0709cc2 100644
--- a/src/plugins/cppeditor/cppcodestylesettingspage.cpp
+++ b/src/plugins/cppeditor/cppcodestylesettingspage.cpp
@@ -45,7 +45,8 @@ static void applyRefactorings(QTextDocument *textDocument, TextEditorWidget *edi
     Environment env;
     Preprocessor preprocess(nullptr, &env);
     const QByteArray preprocessedSource
-        = preprocess.run(QLatin1String("<no-file>"), textDocument->toPlainText().toUtf8());
+        = preprocess.run(Utils::FilePath::fromParts({}, {}, u"<no-file>"),
+                         textDocument->toPlainText().toUtf8());
 
     Document::Ptr cppDocument = Document::create(QLatin1String("<no-file>"));
     cppDocument->setUtf8Source(preprocessedSource);
diff --git a/src/plugins/cppeditor/cppcompletion_test.cpp b/src/plugins/cppeditor/cppcompletion_test.cpp
index 4721b2775e7..7fa42a4be98 100644
--- a/src/plugins/cppeditor/cppcompletion_test.cpp
+++ b/src/plugins/cppeditor/cppcompletion_test.cpp
@@ -26,9 +26,11 @@
 /*!
     Tests for code completion.
  */
+
+using namespace Core;
 using namespace CPlusPlus;
 using namespace TextEditor;
-using namespace Core;
+using namespace Utils;
 
 namespace CppEditor::Internal {
 namespace {
@@ -53,11 +55,11 @@ public:
         m_temporaryDir.reset(new CppEditor::Tests::TemporaryDir());
         QVERIFY(m_temporaryDir->isValid());
         const QByteArray fileExt = isObjC ? "mm" : "h";
-        const QString fileName = m_temporaryDir->createFile("file." + fileExt, m_source);
-        QVERIFY(!fileName.isEmpty());
+        const FilePath filePath = m_temporaryDir->createFile("file." + fileExt, m_source);
+        QVERIFY(!filePath.isEmpty());
 
         // Open in editor
-        m_editor = EditorManager::openEditor(Utils::FilePath::fromString(fileName));
+        m_editor = EditorManager::openEditor(filePath);
         QVERIFY(m_editor);
         closeEditorAtEndOfTestCase(m_editor);
         m_editorWidget = TextEditorWidget::fromEditor(m_editor);
@@ -66,7 +68,7 @@ public:
         m_textDocument = m_editorWidget->document();
 
         // Get Document
-        const Document::Ptr document = waitForFileInGlobalSnapshot(fileName);
+        const Document::Ptr document = waitForFileInGlobalSnapshot(filePath.toString());
         QVERIFY(document);
         QVERIFY(document->diagnosticMessages().isEmpty());
 
diff --git a/src/plugins/cppeditor/cppcompletionassist.cpp b/src/plugins/cppeditor/cppcompletionassist.cpp
index 6aa677aaba3..b8330aadb27 100644
--- a/src/plugins/cppeditor/cppcompletionassist.cpp
+++ b/src/plugins/cppeditor/cppcompletionassist.cpp
@@ -1480,7 +1480,7 @@ bool InternalCppCompletionAssistProcessor::globalCompletion(Scope *currentScope)
 
     addKeywords();
     addMacros(CppModelManager::configurationFileName(), context.snapshot());
-    addMacros(context.thisDocument()->fileName(), context.snapshot());
+    addMacros(context.thisDocument()->filePath().toString(), context.snapshot());
     addSnippets();
     return !m_completions.isEmpty();
 }
@@ -1860,10 +1860,10 @@ void InternalCppCompletionAssistProcessor::addMacros_helper(const Snapshot &snap
 {
     Document::Ptr doc = snapshot.document(fileName);
 
-    if (!doc || processed->contains(doc->fileName()))
+    if (!doc || processed->contains(doc->filePath().path()))
         return;
 
-    processed->insert(doc->fileName());
+    processed->insert(doc->filePath().path());
 
     const QList<Document::Include> includes = doc->resolvedIncludes();
     for (const Document::Include &i : includes)
diff --git a/src/plugins/cppeditor/cppcurrentdocumentfilter.cpp b/src/plugins/cppeditor/cppcurrentdocumentfilter.cpp
index 597c289f85f..965c5d42260 100644
--- a/src/plugins/cppeditor/cppcurrentdocumentfilter.cpp
+++ b/src/plugins/cppeditor/cppcurrentdocumentfilter.cpp
@@ -119,7 +119,7 @@ void CppCurrentDocumentFilter::accept(const Core::LocatorFilterEntry &selection,
 void CppCurrentDocumentFilter::onDocumentUpdated(Document::Ptr doc)
 {
     QMutexLocker locker(&m_mutex);
-    if (m_currentFileName == doc->fileName())
+    if (m_currentFileName == doc->filePath())
         m_itemsOfCurrentDoc.clear();
 }
 
@@ -127,7 +127,7 @@ void CppCurrentDocumentFilter::onCurrentEditorChanged(Core::IEditor *currentEdit
 {
     QMutexLocker locker(&m_mutex);
     if (currentEditor)
-        m_currentFileName = currentEditor->document()->filePath().toString();
+        m_currentFileName = currentEditor->document()->filePath();
     else
         m_currentFileName.clear();
     m_itemsOfCurrentDoc.clear();
@@ -139,7 +139,7 @@ void CppCurrentDocumentFilter::onEditorAboutToClose(Core::IEditor *editorAboutTo
         return;
 
     QMutexLocker locker(&m_mutex);
-    if (m_currentFileName == editorAboutToClose->document()->filePath().toString()) {
+    if (m_currentFileName == editorAboutToClose->document()->filePath()) {
         m_currentFileName.clear();
         m_itemsOfCurrentDoc.clear();
     }
diff --git a/src/plugins/cppeditor/cppcurrentdocumentfilter.h b/src/plugins/cppeditor/cppcurrentdocumentfilter.h
index ab717dace69..26caa0bcbd5 100644
--- a/src/plugins/cppeditor/cppcurrentdocumentfilter.h
+++ b/src/plugins/cppeditor/cppcurrentdocumentfilter.h
@@ -41,7 +41,7 @@ private:
     SearchSymbols search;
 
     mutable QMutex m_mutex;
-    QString m_currentFileName;
+    Utils::FilePath m_currentFileName;
     QList<IndexItem::Ptr> m_itemsOfCurrentDoc;
 };
 
diff --git a/src/plugins/cppeditor/cppdoxygen_test.cpp b/src/plugins/cppeditor/cppdoxygen_test.cpp
index 989c4b01cee..0b749d79063 100644
--- a/src/plugins/cppeditor/cppdoxygen_test.cpp
+++ b/src/plugins/cppeditor/cppdoxygen_test.cpp
@@ -21,6 +21,8 @@ using CppEditor::Tests::TemporaryDir;
 using CppEditor::Tests::TestCase;
 using CppEditor::Internal::Tests::VerifyCleanCppModelManager;
 
+using namespace Utils;
+
 namespace CppEditor {
 namespace Internal {
 namespace Tests {
@@ -425,7 +427,7 @@ void DoxygenTest::runTest(const QByteArray &original,
     }
 
     // Update Code Model
-    QVERIFY(TestCase::parseFiles(testDocument.filePath()));
+    QVERIFY(TestCase::parseFiles(testDocument.filePath().toString()));
 
     // Open Editor
     QVERIFY(TestCase::openCppEditor(testDocument.filePath(), &testDocument.m_editor,
diff --git a/src/plugins/cppeditor/cppeditordocument.cpp b/src/plugins/cppeditor/cppeditordocument.cpp
index 7aed0348ddf..a60cd9660ac 100644
--- a/src/plugins/cppeditor/cppeditordocument.cpp
+++ b/src/plugins/cppeditor/cppeditordocument.cpp
@@ -496,7 +496,7 @@ void CppEditorDocument::onDiagnosticsChanged(const QString &fileName, const QStr
     const Utils::Id category = Utils::Id::fromString(kind);
 
     for (const auto &diagnostic : mm()->diagnosticMessages()) {
-        if (FilePath::fromString(diagnostic.fileName()) == filePath()) {
+        if (diagnostic.filePath() == filePath()) {
             auto it = std::find_if(std::begin(removedMarks),
                                    std::end(removedMarks),
                                    [&category, &diagnostic](TextMark *existing) {
diff --git a/src/plugins/cppeditor/cppfindreferences.cpp b/src/plugins/cppeditor/cppfindreferences.cpp
index 5d100007b46..dc9cb0fd645 100644
--- a/src/plugins/cppeditor/cppfindreferences.cpp
+++ b/src/plugins/cppeditor/cppfindreferences.cpp
@@ -239,7 +239,7 @@ public:
           categorize(categorize)
     { }
 
-    QList<CPlusPlus::Usage> operator()(const Utils::FilePath &fileName)
+    QList<CPlusPlus::Usage> operator()(const Utils::FilePath &filePath)
     {
         QList<CPlusPlus::Usage> usages;
         if (future->isPaused())
@@ -248,18 +248,18 @@ public:
             return usages;
         const CPlusPlus::Identifier *symbolId = symbol->identifier();
 
-        if (CPlusPlus::Document::Ptr previousDoc = snapshot.document(fileName)) {
+        if (CPlusPlus::Document::Ptr previousDoc = snapshot.document(filePath)) {
             CPlusPlus::Control *control = previousDoc->control();
             if (!control->findIdentifier(symbolId->chars(), symbolId->size()))
                 return usages; // skip this document, it's not using symbolId.
         }
         CPlusPlus::Document::Ptr doc;
-        const QByteArray unpreprocessedSource = getSource(fileName, workingCopy);
+        const QByteArray unpreprocessedSource = getSource(filePath, workingCopy);
 
-        if (symbolDocument && fileName == Utils::FilePath::fromString(symbolDocument->fileName())) {
+        if (symbolDocument && filePath == symbolDocument->filePath()) {
             doc = symbolDocument;
         } else {
-            doc = snapshot.preprocessedDocument(unpreprocessedSource, fileName);
+            doc = snapshot.preprocessedDocument(unpreprocessedSource, filePath);
             doc->tokenize();
         }
 
@@ -541,10 +541,9 @@ CPlusPlus::Symbol *CppFindReferences::findSymbol(const CppFindReferencesParamete
 
     CPlusPlus::Document::Ptr newSymbolDocument = snapshot.document(symbolFile);
     // document is not parsed and has no bindings yet, do it
-    QByteArray source = getSource(Utils::FilePath::fromString(newSymbolDocument->fileName()),
-                                  m_modelManager->workingCopy());
+    QByteArray source = getSource(newSymbolDocument->filePath(), m_modelManager->workingCopy());
     CPlusPlus::Document::Ptr doc =
-            snapshot.preprocessedDocument(source, FilePath::fromString(newSymbolDocument->fileName()));
+            snapshot.preprocessedDocument(source, newSymbolDocument->filePath());
     doc->check();
 
     // find matching symbol in new document and return the new parameters
diff --git a/src/plugins/cppeditor/cppfollowsymbolundercursor.cpp b/src/plugins/cppeditor/cppfollowsymbolundercursor.cpp
index 499549638eb..7e86acfc123 100644
--- a/src/plugins/cppeditor/cppfollowsymbolundercursor.cpp
+++ b/src/plugins/cppeditor/cppfollowsymbolundercursor.cpp
@@ -182,8 +182,8 @@ Class *VirtualFunctionHelper::staticClassOfFunctionCallExpression_internal() con
 Link findMacroLink_helper(const QByteArray &name, Document::Ptr doc, const Snapshot &snapshot,
                           QSet<QString> *processed)
 {
-    if (doc && !name.startsWith('<') && !processed->contains(doc->fileName())) {
-        processed->insert(doc->fileName());
+    if (doc && !name.startsWith('<') && !processed->contains(doc->filePath().path())) {
+        processed->insert(doc->filePath().path());
 
         for (const Macro &macro : doc->definedMacros()) {
             if (macro.name() == name) {
diff --git a/src/plugins/cppeditor/cppfunctiondecldeflink.cpp b/src/plugins/cppeditor/cppfunctiondecldeflink.cpp
index be78b1bffbc..c5d1b364cd3 100644
--- a/src/plugins/cppeditor/cppfunctiondecldeflink.cpp
+++ b/src/plugins/cppeditor/cppfunctiondecldeflink.cpp
@@ -198,8 +198,7 @@ void FunctionDeclDefLinkFinder::startFindLinkAt(
 
     // find the start/end offsets
     CppRefactoringChanges refactoringChanges(snapshot);
-    CppRefactoringFilePtr sourceFile = refactoringChanges.file(
-        Utils::FilePath::fromString(doc->fileName()));
+    CppRefactoringFilePtr sourceFile = refactoringChanges.file(doc->filePath());
     sourceFile->setCppDocument(doc);
     int start, end;
     declDefLinkStartEnd(sourceFile, parent, funcDecl, &start, &end);
diff --git a/src/plugins/cppeditor/cppincludehierarchy_test.cpp b/src/plugins/cppeditor/cppincludehierarchy_test.cpp
index 1d3d69fad64..d3d0bf03976 100644
--- a/src/plugins/cppeditor/cppincludehierarchy_test.cpp
+++ b/src/plugins/cppeditor/cppincludehierarchy_test.cpp
@@ -17,6 +17,7 @@
 #include <QtTest>
 
 using namespace CPlusPlus;
+using namespace Utils;
 
 using CppEditor::Tests::TemporaryDir;
 
@@ -56,7 +57,7 @@ public:
     {
         QVERIFY(succeededSoFar());
 
-        QSet<QString> filePaths;
+        QSet<FilePath> filePaths;
         const int sourceListSize = sourceList.size();
 
         TemporaryDir temporaryDir;
@@ -67,14 +68,13 @@ public:
 
             // Write source to file
             const QString fileName = QString::fromLatin1("file%1.h").arg(i+1);
-            const QString absoluteFilePath = temporaryDir.createFile(fileName.toLatin1(), source);
-            filePaths << absoluteFilePath;
+            filePaths << temporaryDir.createFile(fileName.toLatin1(), source);
         }
 
         // Open Editor
-        const QString fileName = temporaryDir.path() + QLatin1String("/file1.h");
+        const Utils::FilePath filePath = temporaryDir.filePath() / "file1.h";
         TextEditor::BaseTextEditor *editor;
-        QVERIFY(openCppEditor(fileName, &editor));
+        QVERIFY(openCppEditor(filePath, &editor));
         closeEditorAtEndOfTestCase(editor);
 
         // Update Code Model
diff --git a/src/plugins/cppeditor/cpplocatordata.cpp b/src/plugins/cppeditor/cpplocatordata.cpp
index 3349011ce91..11eed8c74a8 100644
--- a/src/plugins/cppeditor/cpplocatordata.cpp
+++ b/src/plugins/cppeditor/cpplocatordata.cpp
@@ -25,7 +25,7 @@ void CppLocatorData::onDocumentUpdated(const CPlusPlus::Document::Ptr &document)
     bool isPending = false;
     for (int i = 0, ei = m_pendingDocuments.size(); i < ei; ++i) {
         const CPlusPlus::Document::Ptr &doc = m_pendingDocuments.at(i);
-        if (doc->fileName() == document->fileName()) {
+        if (doc->filePath() == document->filePath()) {
             isPending = true;
             if (document->revision() >= doc->revision())
                 m_pendingDocuments[i] = document;
@@ -33,7 +33,7 @@ void CppLocatorData::onDocumentUpdated(const CPlusPlus::Document::Ptr &document)
         }
     }
 
-    if (!isPending && QFileInfo(document->fileName()).suffix() != "moc")
+    if (!isPending && document->filePath().suffix() != "moc")
         m_pendingDocuments.append(document);
 
     flushPendingDocument(false);
@@ -50,7 +50,7 @@ void CppLocatorData::onAboutToRemoveFiles(const QStringList &files)
         m_infosByFile.remove(file);
 
         for (int i = 0; i < m_pendingDocuments.size(); ++i) {
-            if (m_pendingDocuments.at(i)->fileName() == file) {
+            if (m_pendingDocuments.at(i)->filePath().path() == file) {
                 m_pendingDocuments.remove(i);
                 break;
             }
@@ -70,7 +70,7 @@ void CppLocatorData::flushPendingDocument(bool force) const
         return;
 
     for (CPlusPlus::Document::Ptr doc : std::as_const(m_pendingDocuments))
-        m_infosByFile.insert(Internal::StringTable::insert(doc->fileName()), m_search(doc));
+        m_infosByFile.insert(Internal::StringTable::insert(doc->filePath()), m_search(doc));
 
     m_pendingDocuments.clear();
     m_pendingDocuments.reserve(MaxPendingDocuments);
diff --git a/src/plugins/cppeditor/cppmodelmanager.cpp b/src/plugins/cppeditor/cppmodelmanager.cpp
index 3a066abcb4e..884e5d31755 100644
--- a/src/plugins/cppeditor/cppmodelmanager.cpp
+++ b/src/plugins/cppeditor/cppmodelmanager.cpp
@@ -263,10 +263,10 @@ QSet<QString> CppModelManager::timeStampModifiedFiles(const QList<Document::Ptr>
         const QDateTime lastModified = doc->lastModified();
 
         if (!lastModified.isNull()) {
-            QFileInfo fileInfo(doc->fileName());
+            const FilePath filePath = doc->filePath();
 
-            if (fileInfo.exists() && fileInfo.lastModified() != lastModified)
-                sourceFiles.insert(doc->fileName());
+            if (filePath.exists() && filePath.lastModified() != lastModified)
+                sourceFiles.insert(filePath.toString());
         }
     }
 
@@ -286,7 +286,7 @@ CppSourceProcessor *CppModelManager::createSourceProcessor()
 {
     CppModelManager *that = instance();
     return new CppSourceProcessor(that->snapshot(), [that](const Document::Ptr &doc) {
-        const Document::Ptr previousDocument = that->document(doc->fileName());
+        const Document::Ptr previousDocument = that->document(doc->filePath());
         const unsigned newRevision = previousDocument.isNull()
                 ? 1U
                 : previousDocument->revision() + 1;
@@ -816,10 +816,10 @@ Snapshot CppModelManager::snapshot() const
     return d->m_snapshot;
 }
 
-Document::Ptr CppModelManager::document(const QString &fileName) const
+Document::Ptr CppModelManager::document(const FilePath &filePath) const
 {
     QMutexLocker locker(&d->m_snapshotMutex);
-    return d->m_snapshot.document(fileName);
+    return d->m_snapshot.document(filePath);
 }
 
 /// Replace the document in the snapshot.
@@ -829,7 +829,7 @@ bool CppModelManager::replaceDocument(Document::Ptr newDoc)
 {
     QMutexLocker locker(&d->m_snapshotMutex);
 
-    Document::Ptr previous = d->m_snapshot.document(newDoc->fileName());
+    Document::Ptr previous = d->m_snapshot.document(newDoc->filePath());
     if (previous && (newDoc->revision() != 0 && newDoc->revision() < previous->revision()))
         // the new document is outdated
         return false;
@@ -1617,7 +1617,7 @@ void CppModelManager::renameIncludes(const Utils::FilePath &oldFilePath,
     const QList<Snapshot::IncludeLocation> locations = snapshot().includeLocationsOfDocument(
         isUiFile ? oldFileName : oldFilePath.toString());
     for (const Snapshot::IncludeLocation &loc : locations) {
-        const auto filePath = FilePath::fromString(loc.first->fileName());
+        const FilePath filePath = loc.first->filePath();
 
         // Larger projects can easily have more than one ui file with the same name.
         // Replace only if ui file and including source file belong to the same product.
diff --git a/src/plugins/cppeditor/cppmodelmanager.h b/src/plugins/cppeditor/cppmodelmanager.h
index 221672d979a..5e5b19a3a1c 100644
--- a/src/plugins/cppeditor/cppmodelmanager.h
+++ b/src/plugins/cppeditor/cppmodelmanager.h
@@ -118,7 +118,7 @@ public:
     ProjectPart::ConstPtr fallbackProjectPart();
 
     CPlusPlus::Snapshot snapshot() const override;
-    Document::Ptr document(const QString &fileName) const;
+    Document::Ptr document(const Utils::FilePath &filePath) const;
     bool replaceDocument(Document::Ptr newDoc);
 
     void emitDocumentUpdated(Document::Ptr doc);
diff --git a/src/plugins/cppeditor/cppmodelmanager_test.cpp b/src/plugins/cppeditor/cppmodelmanager_test.cpp
index 42ce1809472..ed1ac752682 100644
--- a/src/plugins/cppeditor/cppmodelmanager_test.cpp
+++ b/src/plugins/cppeditor/cppmodelmanager_test.cpp
@@ -33,6 +33,7 @@
     QCOMPARE(document->revision(), expectedRevision);
 
 using namespace ProjectExplorer;
+using namespace Utils;
 
 using CPlusPlus::Document;
 
@@ -66,6 +67,11 @@ public:
 
     QString fileFromSourcesDir(const QString &fileName) const
     { return directory(_("sources")) + QLatin1Char('/') + fileName; }
+
+    FilePath filePath(const QString &p) const
+    {
+        return FilePath::fromString(TestDataDir::file(p));
+    }
 };
 
 QStringList toAbsolutePaths(const QStringList &relativePathList,
@@ -113,7 +119,7 @@ public:
 class FileChangerAndRestorer
 {
 public:
-    explicit FileChangerAndRestorer(const QString &filePath)
+    explicit FileChangerAndRestorer(const Utils::FilePath &filePath)
         : m_filePath(filePath)
     {
     }
@@ -127,7 +133,7 @@ public:
     bool readContents(QByteArray *contents)
     {
         Utils::FileReader fileReader;
-        const bool isFetchOk = fileReader.fetch(Utils::FilePath::fromString(m_filePath));
+        const bool isFetchOk = fileReader.fetch(m_filePath);
         if (isFetchOk) {
             m_originalFileContents = fileReader.data();
             if (contents)
@@ -148,7 +154,7 @@ private:
     }
 
     QByteArray m_originalFileContents;
-    const QString &m_filePath;
+    const Utils::FilePath m_filePath;
 };
 
 ProjectPart::ConstPtr projectPartOfEditorDocument(const QString &filePath)
@@ -216,7 +222,7 @@ void ModelManagerTest::testFrameworkHeaders()
     QCoreApplication::processEvents();
 
     QVERIFY(mm->snapshot().contains(source));
-    Document::Ptr doc = mm->document(source);
+    Document::Ptr doc = mm->document(Utils::FilePath::fromString(source));
     QVERIFY(!doc.isNull());
     CPlusPlus::Namespace *ns = doc->globalNamespace();
     QVERIFY(ns);
@@ -482,7 +488,7 @@ void ModelManagerTest::testRefreshTimeStampModifiedIfSourcefilesChange()
 
     // Modify the file
     QTest::qSleep(1000); // Make sure the timestamp is different
-    FileChangerAndRestorer fileChangerAndRestorer(fileToChange);
+    FileChangerAndRestorer fileChangerAndRestorer(FilePath::fromString(fileToChange));
     QByteArray originalContents;
     QVERIFY(fileChangerAndRestorer.readContents(&originalContents));
     const QByteArray newFileContentes = originalContents + "\nint addedOtherGlobal;";
@@ -762,16 +768,15 @@ void ModelManagerTest::testDefinesPerProject()
 
     for (auto &i : d) {
         const QString firstDeclarationName = i.firstDeclarationName;
-        const QString fileName = i.fileName;
+        const Utils::FilePath filePath = Utils::FilePath::fromString(i.fileName);
 
-        Core::IEditor *editor = Core::EditorManager::openEditor(
-            Utils::FilePath::fromString(fileName));
+        Core::IEditor *editor = Core::EditorManager::openEditor(filePath);
         EditorCloser closer(editor);
         QVERIFY(editor);
         QCOMPARE(Core::DocumentModel::openedDocuments().size(), 1);
         QVERIFY(mm->isCppEditor(editor));
 
-        Document::Ptr doc = mm->document(fileName);
+        Document::Ptr doc = mm->document(filePath);
         QCOMPARE(nameOfFirstDeclaration(doc), firstDeclarationName);
     }
 }
@@ -845,7 +850,7 @@ void ModelManagerTest::testPrecompiledHeaders()
                         Utils::Language::Cxx, false});
 
         // Check if defines from pch are considered
-        Document::Ptr document = mm->document(fileName);
+        Document::Ptr document = mm->document(Utils::FilePath::fromString(fileName));
         QCOMPARE(nameOfFirstDeclaration(document), firstDeclarationName);
 
         // Check if declarations from pch are considered
@@ -919,7 +924,7 @@ void ModelManagerTest::testDefinesPerEditor()
         parser->update({CppModelManager::instance()->workingCopy(), nullptr,
                         Utils::Language::Cxx, false});
 
-        Document::Ptr doc = mm->document(main1File);
+        Document::Ptr doc = mm->document(FilePath::fromString(main1File));
         QCOMPARE(nameOfFirstDeclaration(doc), firstDeclarationName);
     }
 }
@@ -1154,9 +1159,9 @@ void ModelManagerTest::testDocumentsAndRevisions()
 
     // Index two files
     const MyTestDataDir testDir(_("testdata_project1"));
-    const QString filePath1 = testDir.file(QLatin1String("foo.h"));
-    const QString filePath2 = testDir.file(QLatin1String("foo.cpp"));
-    const QSet<QString> filesToIndex = {filePath1,filePath2};
+    const FilePath filePath1 = testDir.filePath(QLatin1String("foo.h"));
+    const FilePath filePath2 = testDir.filePath(QLatin1String("foo.cpp"));
+    const QSet<FilePath> filesToIndex = {filePath1,filePath2};
     QVERIFY(TestCase::parseFiles(filesToIndex));
 
     CppModelManager *modelManager = CppModelManager::instance();
@@ -1167,7 +1172,7 @@ void ModelManagerTest::testDocumentsAndRevisions()
     TextEditor::BaseTextEditor *editor1;
     QVERIFY(helper.openCppEditor(filePath1, &editor1));
     helper.closeEditorAtEndOfTestCase(editor1);
-    QVERIFY(TestCase::waitForProcessedEditorDocument(filePath1));
+    QVERIFY(TestCase::waitForProcessedEditorDocument(filePath1.toString()));
     VERIFY_DOCUMENT_REVISION(modelManager->document(filePath1), 2U);
     VERIFY_DOCUMENT_REVISION(modelManager->document(filePath2), 1U);
 
@@ -1180,7 +1185,7 @@ void ModelManagerTest::testDocumentsAndRevisions()
     TextEditor::BaseTextEditor *editor2;
     QVERIFY(helper.openCppEditor(filePath2, &editor2));
     helper.closeEditorAtEndOfTestCase(editor2);
-    QVERIFY(TestCase::waitForProcessedEditorDocument(filePath2));
+    QVERIFY(TestCase::waitForProcessedEditorDocument(filePath2.toString()));
     VERIFY_DOCUMENT_REVISION(modelManager->document(filePath1), 3U);
     VERIFY_DOCUMENT_REVISION(modelManager->document(filePath2), 3U);
 
diff --git a/src/plugins/cppeditor/cpppointerdeclarationformatter_test.cpp b/src/plugins/cppeditor/cpppointerdeclarationformatter_test.cpp
index 06134ee3fcd..0a5f88ab9aa 100644
--- a/src/plugins/cppeditor/cpppointerdeclarationformatter_test.cpp
+++ b/src/plugins/cppeditor/cpppointerdeclarationformatter_test.cpp
@@ -24,6 +24,7 @@
 #include <QtTest>
 
 using namespace CPlusPlus;
+using namespace Utils;
 
 Q_DECLARE_METATYPE(CppEditor::Internal::Overview)
 
@@ -63,15 +64,15 @@ public:
         // Write source to temprorary file
         CppEditor::Tests::TemporaryDir temporaryDir;
         QVERIFY(temporaryDir.isValid());
-        const QString filePath = temporaryDir.createFile("file.h", sourceWithoutCursorMarker);
+        const FilePath filePath = temporaryDir.createFile("file.h", sourceWithoutCursorMarker);
         QVERIFY(!filePath.isEmpty());
 
         // Preprocess source
-        Environment env;
+        CPlusPlus::Environment env;
         Preprocessor preprocess(nullptr, &env);
         const QByteArray preprocessedSource = preprocess.run(filePath, sourceWithoutCursorMarker);
 
-        Document::Ptr document = Document::create(filePath);
+        Document::Ptr document = Document::create(filePath.toString());
         document->setUtf8Source(preprocessedSource);
         document->parse(parseMode);
         document->check();
@@ -83,9 +84,7 @@ public:
         QScopedPointer<TextEditor::BaseTextEditor> editor(
                     TextEditor::PlainTextEditorFactory::createPlainTextEditor());
         QString error;
-        editor->document()->open(&error,
-                                 Utils::FilePath::fromString(document->fileName()),
-                                 Utils::FilePath::fromString(document->fileName()));
+        editor->document()->open(&error, document->filePath(), document->filePath());
         QVERIFY(error.isEmpty());
 
         // Set cursor position
diff --git a/src/plugins/cppeditor/cppquickfix_test.cpp b/src/plugins/cppeditor/cppquickfix_test.cpp
index bbd192f7f74..1aaa4c8a5cb 100644
--- a/src/plugins/cppeditor/cppquickfix_test.cpp
+++ b/src/plugins/cppeditor/cppquickfix_test.cpp
@@ -25,6 +25,7 @@
 using namespace Core;
 using namespace CPlusPlus;
 using namespace TextEditor;
+using namespace Utils;
 
 using CppEditor::Tests::TemporaryDir;
 using CppEditor::Tests::Internal::TestIncludePaths;
@@ -92,7 +93,7 @@ BaseQuickFixTestCase::BaseQuickFixTestCase(const QList<TestDocumentPtr> &testDoc
     }
 
     // Update Code Model
-    QSet<QString> filePaths;
+    QSet<FilePath> filePaths;
     for (const TestDocumentPtr &document : std::as_const(m_testDocuments))
         filePaths << document->filePath();
     QVERIFY(parseFiles(filePaths));
@@ -150,7 +151,7 @@ BaseQuickFixTestCase::~BaseQuickFixTestCase()
 
     // Remove created files from file system
     for (const TestDocumentPtr &testDocument : std::as_const(m_testDocuments))
-        QVERIFY(QFile::remove(testDocument->filePath()));
+        QVERIFY(testDocument->filePath().removeFile());
 }
 
 /// Leading whitespace is not removed, so we can check if the indetation ranges
diff --git a/src/plugins/cppeditor/cppquickfixes.cpp b/src/plugins/cppeditor/cppquickfixes.cpp
index 0c33c377332..33819ec4455 100644
--- a/src/plugins/cppeditor/cppquickfixes.cpp
+++ b/src/plugins/cppeditor/cppquickfixes.cpp
@@ -80,7 +80,7 @@
 
 using namespace CPlusPlus;
 using namespace TextEditor;
-using Utils::ChangeSet;
+using namespace Utils;
 
 namespace CppEditor {
 
@@ -2056,7 +2056,7 @@ void AddIncludeForUndefinedIdentifier::match(const CppQuickFixInterface &interfa
 
     QString className;
     QList<Core::LocatorFilterEntry> matches;
-    const QString currentDocumentFilePath = interface.semanticInfo().doc->fileName();
+    const QString currentDocumentFilePath = interface.semanticInfo().doc->filePath().toString();
     const ProjectExplorer::HeaderPaths headerPaths = relevantHeaderPaths(currentDocumentFilePath);
     QList<Utils::FilePath> headers;
 
@@ -2530,7 +2530,7 @@ public:
                         const QString &targetFileName, const Class *targetSymbol,
                         InsertionPointLocator::AccessSpec xsSpec, const QString &decl, int priority)
         : CppQuickFixOperation(interface, priority)
-        , m_targetFileName(targetFileName)
+        , m_targetFileName(FilePath::fromString(targetFileName))
         , m_targetSymbol(targetSymbol)
         , m_xsSpec(xsSpec)
         , m_decl(decl)
@@ -2549,8 +2549,7 @@ public:
                     m_targetFileName, m_targetSymbol, m_xsSpec);
         QTC_ASSERT(loc.isValid(), return);
 
-        CppRefactoringFilePtr targetFile = refactoring.file(
-            Utils::FilePath::fromString(m_targetFileName));
+        CppRefactoringFilePtr targetFile = refactoring.file(m_targetFileName);
         int targetPosition1 = targetFile->position(loc.line(), loc.column());
         int targetPosition2 = qMax(0, targetFile->position(loc.line(), 1) - 1);
 
@@ -2565,7 +2564,7 @@ public:
     static QString generateDeclaration(const Function *function);
 
 private:
-    QString m_targetFileName;
+    FilePath m_targetFileName;
     const Class *m_targetSymbol;
     InsertionPointLocator::AccessSpec m_xsSpec;
     QString m_decl;
@@ -2985,12 +2984,12 @@ private:
 
         const CppRefactoringChanges refactoring(snapshot());
         const InsertionPointLocator locator(refactoring);
-        const QString filePath = QString::fromUtf8(m_class->fileName());
+        const FilePath filePath = FilePath::fromUtf8(m_class->fileName());
         const InsertionLocation loc = locator.methodDeclarationInClass(
                     filePath, m_class, InsertionPointLocator::Private);
         QTC_ASSERT(loc.isValid(), return);
 
-        CppRefactoringFilePtr targetFile = refactoring.file(Utils::FilePath::fromString(filePath));
+        CppRefactoringFilePtr targetFile = refactoring.file(filePath);
         const int targetPosition1 = targetFile->position(loc.line(), loc.column());
         const int targetPosition2 = qMax(0, targetFile->position(loc.line(), 1) - 1);
         ChangeSet target;
@@ -3633,7 +3632,7 @@ protected:
         if (insertionPoint != m_headerInsertionPoints.end())
             return *insertionPoint;
         const InsertionLocation loc = m_locator.methodDeclarationInClass(
-                    m_headerFile->filePath().toString(), m_class, spec,
+                    m_headerFile->filePath(), m_class, spec,
                     InsertionPointLocator::ForceAccessSpec::Yes);
         m_headerInsertionPoints.insert(spec, loc);
         return loc;
@@ -4943,10 +4942,10 @@ public:
         // Write declaration, if necessary.
         if (matchingClass) {
             InsertionPointLocator locator(refactoring);
-            const QString fileName = QLatin1String(matchingClass->fileName());
+            const FilePath filePath = FilePath::fromUtf8(matchingClass->fileName());
             const InsertionLocation &location =
-                    locator.methodDeclarationInClass(fileName, matchingClass, options.access);
-            CppRefactoringFilePtr declFile = refactoring.file(Utils::FilePath::fromString(fileName));
+                    locator.methodDeclarationInClass(filePath, matchingClass, options.access);
+            CppRefactoringFilePtr declFile = refactoring.file(filePath);
             change.clear();
             position = declFile->position(location.line(), location.column());
             change.insert(position, location.prefix() + funcDecl + location.suffix());
@@ -8081,8 +8080,7 @@ private:
         while (!nodesWithProcessedParents.empty()) {
             Node &node = nodesWithProcessedParents.back();
             nodesWithProcessedParents.pop_back();
-            CppRefactoringFilePtr file = refactoring.file(
-                Utils::FilePath::fromString(node.document->fileName()));
+            CppRefactoringFilePtr file = refactoring.file(node.document->filePath());
             const bool parentHasUsing = Utils::anyOf(node.includes, &Node::hasGlobalUsingDirective);
             const int startPos = parentHasUsing
                                      ? 0
@@ -8154,14 +8152,13 @@ private:
             if (m_processed.contains(loc.first))
                 continue;
 
-            CppRefactoringFilePtr file = refactoring.file(
-                Utils::FilePath::fromString(loc.first->fileName()));
+            CppRefactoringFilePtr file = refactoring.file(loc.first->filePath());
             const bool noGlobalUsing = refactorFile(file,
                                                     refactoring.snapshot(),
                                                     file->position(loc.second, 1));
             m_processed.insert(loc.first);
             if (noGlobalUsing)
-                processIncludes(refactoring, loc.first->fileName());
+                processIncludes(refactoring, loc.first->filePath().toString());
         }
     }
 
diff --git a/src/plugins/cppeditor/cppsemanticinfoupdater.cpp b/src/plugins/cppeditor/cppsemanticinfoupdater.cpp
index 12ee180b5c0..7d4aca6f9bf 100644
--- a/src/plugins/cppeditor/cppsemanticinfoupdater.cpp
+++ b/src/plugins/cppeditor/cppsemanticinfoupdater.cpp
@@ -121,7 +121,7 @@ bool SemanticInfoUpdaterPrivate::reuseCurrentSemanticInfo(const SemanticInfo::So
             && currentSemanticInfo.revision == source.revision
             && currentSemanticInfo.doc
             && currentSemanticInfo.doc->translationUnit()->ast()
-            && currentSemanticInfo.doc->fileName() == source.fileName
+            && currentSemanticInfo.doc->filePath().toString() == source.fileName
             && !currentSemanticInfo.snapshot.isEmpty()
             && currentSemanticInfo.snapshot == source.snapshot) {
         SemanticInfo newSemanticInfo;
diff --git a/src/plugins/cppeditor/cppsourceprocessor.cpp b/src/plugins/cppeditor/cppsourceprocessor.cpp
index 35cea8f1427..3f1d18c0896 100644
--- a/src/plugins/cppeditor/cppsourceprocessor.cpp
+++ b/src/plugins/cppeditor/cppsourceprocessor.cpp
@@ -66,7 +66,7 @@ inline Message messageNoSuchFile(Document::Ptr &document, const QString &fileNam
 {
     const QString text = QCoreApplication::translate(
         "CppSourceProcessor", "%1: No such file or directory").arg(fileName);
-    return Message(Message::Warning, document->fileName(), line, /*column =*/ 0, text);
+    return Message(Message::Warning, document->filePath(), line, /*column =*/ 0, text);
 }
 
 inline Message messageNoFileContents(Document::Ptr &document, const QString &fileName,
@@ -74,7 +74,7 @@ inline Message messageNoFileContents(Document::Ptr &document, const QString &fil
 {
     const QString text = QCoreApplication::translate(
         "CppSourceProcessor", "%1: Could not get file contents").arg(fileName);
-    return Message(Message::Warning, document->fileName(), line, /*column =*/ 0, text);
+    return Message(Message::Warning, document->filePath(), line, /*column =*/ 0, text);
 }
 
 inline const CPlusPlus::Macro revision(const WorkingCopy &workingCopy,
@@ -244,7 +244,7 @@ QString CppSourceProcessor::resolveFile(const QString &fileName, IncludeType typ
 
     if (m_currentDoc) {
         if (type == IncludeLocal) {
-            const QFileInfo currentFileInfo(m_currentDoc->fileName());
+            const QFileInfo currentFileInfo = m_currentDoc->filePath().toFileInfo();
             const QString path = cleanPath(currentFileInfo.absolutePath()) + fileName;
             if (checkFile(path))
                 return path;
@@ -252,7 +252,7 @@ QString CppSourceProcessor::resolveFile(const QString &fileName, IncludeType typ
             // searching as if this would be a global include.
 
         } else if (type == IncludeNext) {
-            const QFileInfo currentFileInfo(m_currentDoc->fileName());
+            const QFileInfo currentFileInfo = m_currentDoc->filePath().toFileInfo();
             const QString currentDirPath = cleanPath(currentFileInfo.dir().path());
             auto headerPathsEnd = m_headerPaths.end();
             auto headerPathsIt = m_headerPaths.begin();
@@ -372,7 +372,7 @@ void CppSourceProcessor::mergeEnvironment(Document::Ptr doc)
     if (!doc)
         return;
 
-    const QString fn = doc->fileName();
+    const QString fn = doc->filePath().path();
 
     if (m_processed.contains(fn))
         return;
@@ -457,7 +457,8 @@ void CppSourceProcessor::sourceNeeded(int line, const QString &fileName, Include
         document->setLastModified(info.lastModified());
 
     const Document::Ptr previousDocument = switchCurrentDocument(document);
-    const QByteArray preprocessedCode = m_preprocess.run(absoluteFileName, contents);
+    const QByteArray preprocessedCode =
+            m_preprocess.run(Utils::FilePath::fromString(absoluteFileName), contents);
 //    {
 //        QByteArray b(preprocessedCode); b.replace("\n", "<<<\n");
 //        qDebug("Preprocessed code for \"%s\": [[%s]]", fileName.toUtf8().constData(), b.constData());
@@ -478,7 +479,7 @@ void CppSourceProcessor::sourceNeeded(int line, const QString &fileName, Include
     document->setUtf8Source(preprocessedCode);
     document->keepSourceAndAST();
     document->tokenize();
-    document->check(m_workingCopy.contains(document->fileName()) ? Document::FullCheck
+    document->check(m_workingCopy.contains(document->filePath()) ? Document::FullCheck
                                                                  : Document::FastCheck);
 
     m_documentFinished(document);
diff --git a/src/plugins/cppeditor/cppsourceprocessor_test.cpp b/src/plugins/cppeditor/cppsourceprocessor_test.cpp
index e4c30f97c11..58e0fdf630c 100644
--- a/src/plugins/cppeditor/cppsourceprocessor_test.cpp
+++ b/src/plugins/cppeditor/cppsourceprocessor_test.cpp
@@ -21,7 +21,8 @@
 #include <QtTest>
 
 using namespace CPlusPlus;
-using ProjectExplorer::HeaderPathType;
+using namespace ProjectExplorer;
+using namespace Utils;
 
 using Include = Document::Include;
 using CppEditor::Tests::TestCase;
@@ -46,7 +47,7 @@ public:
                                          TestIncludePaths::directoryOfTestFile())});
         sourceProcessor->run(filePath);
 
-        Document::Ptr document = m_cmm->document(filePath);
+        Document::Ptr document = m_cmm->document(Utils::FilePath::fromString(filePath));
         return document;
     }
 
@@ -96,7 +97,8 @@ void SourceProcessorTest::testIncludesCyclic()
 {
     const QString fileName1 = TestIncludePaths::testFilePath(QLatin1String("cyclic1.h"));
     const QString fileName2 = TestIncludePaths::testFilePath(QLatin1String("cyclic2.h"));
-    const QSet<QString> sourceFiles = {fileName1, fileName2};
+    const QSet<FilePath> sourceFiles = {FilePath::fromString(fileName1),
+                                        FilePath::fromString(fileName2)};
 
     // Create global snapshot (needed in BuiltinEditorDocumentParser)
     TestCase testCase;
@@ -104,7 +106,7 @@ void SourceProcessorTest::testIncludesCyclic()
 
     // Open editor
     TextEditor::BaseTextEditor *editor;
-    QVERIFY(testCase.openCppEditor(fileName1, &editor));
+    QVERIFY(testCase.openCppEditor(FilePath::fromString(fileName1), &editor));
     testCase.closeEditorAtEndOfTestCase(editor);
 
     // Check editor snapshot
@@ -165,7 +167,7 @@ void SourceProcessorTest::testMacroUses()
 
 static bool isMacroDefinedInDocument(const QByteArray &macroName, const Document::Ptr &document)
 {
-    for (const Macro &macro : document->definedMacros()) {
+    for (const CPlusPlus::Macro &macro : document->definedMacros()) {
         if (macro.name() == macroName)
             return true;
     }
diff --git a/src/plugins/cppeditor/cpptoolstestcase.cpp b/src/plugins/cppeditor/cpptoolstestcase.cpp
index 2d83897e96d..2633e41ffbe 100644
--- a/src/plugins/cppeditor/cpptoolstestcase.cpp
+++ b/src/plugins/cppeditor/cpptoolstestcase.cpp
@@ -84,15 +84,15 @@ TestDocumentPtr CppTestDocument::create(const QByteArray &fileName, const QByteA
     return doc;
 }
 
-QString CppTestDocument::filePath() const
+FilePath CppTestDocument::filePath() const
 {
     if (!m_baseDirectory.isEmpty())
-        return QDir::cleanPath(m_baseDirectory + QLatin1Char('/') + m_fileName);
+        return FilePath::fromString(QDir::cleanPath(m_baseDirectory + '/' + m_fileName));
 
     if (!QFileInfo(m_fileName).isAbsolute())
-        return Utils::TemporaryDirectory::masterDirectoryPath() + '/' + m_fileName;
+        return FilePath::fromString(TemporaryDirectory::masterDirectoryPath() + '/' + m_fileName);
 
-    return m_fileName;
+    return FilePath::fromString(m_fileName);
 }
 
 bool CppTestDocument::writeToDisk() const
@@ -212,11 +212,11 @@ bool TestCase::succeededSoFar() const
     return m_succeededSoFar;
 }
 
-bool TestCase::openCppEditor(const QString &fileName, TextEditor::BaseTextEditor **editor,
+bool TestCase::openCppEditor(const FilePath &filePath, TextEditor::BaseTextEditor **editor,
                              CppEditorWidget **editorWidget)
 {
     if (const auto e = dynamic_cast<TextEditor::BaseTextEditor *>(
-            Core::EditorManager::openEditor(FilePath::fromString(fileName)))) {
+            Core::EditorManager::openEditor(filePath))) {
         if (editor) {
             *editor = e;
             TextEditor::StorageSettings s = e->textDocument()->storageSettings();
@@ -281,16 +281,17 @@ CPlusPlus::Document::Ptr TestCase::waitForRehighlightedSemanticDocument(CppEdito
     return editorWidget->semanticInfo().doc;
 }
 
-bool TestCase::parseFiles(const QSet<QString> &filePaths)
+bool TestCase::parseFiles(const QSet<FilePath> &filePaths)
 {
-    CppModelManager::instance()->updateSourceFiles(filePaths).waitForFinished();
+    QSet<QString> filePaths_ = transform(filePaths, &FilePath::toString);
+    CppModelManager::instance()->updateSourceFiles(filePaths_).waitForFinished();
     QCoreApplication::processEvents();
     const CPlusPlus::Snapshot snapshot = globalSnapshot();
     if (snapshot.isEmpty()) {
         qWarning("After parsing: snapshot is empty.");
         return false;
     }
-    if (!snapshotContains(snapshot, filePaths)) {
+    if (!snapshotContains(snapshot, filePaths_)) {
         qWarning("After parsing: snapshot does not contain all expected files.");
         return false;
     }
@@ -299,7 +300,7 @@ bool TestCase::parseFiles(const QSet<QString> &filePaths)
 
 bool TestCase::parseFiles(const QString &filePath)
 {
-    return parseFiles(QSet<QString>{filePath});
+    return parseFiles({FilePath::fromString(filePath)});
 }
 
 void TestCase::closeEditorAtEndOfTestCase(Core::IEditor *editor)
@@ -355,11 +356,11 @@ bool TestCase::waitUntilProjectIsFullyOpened(Project *project, int timeOutInMs)
         timeOutInMs);
 }
 
-bool TestCase::writeFile(const QString &filePath, const QByteArray &contents)
+bool TestCase::writeFile(const FilePath &filePath, const QByteArray &contents)
 {
-    Utils::FileSaver saver(Utils::FilePath::fromString(filePath));
+    Utils::FileSaver saver(filePath);
     if (!saver.write(contents) || !saver.finalize()) {
-        qWarning() << "Failed to write file to disk:" << qPrintable(filePath);
+        qWarning() << "Failed to write file to disk:" << qPrintable(filePath.toUserOutput());
         return false;
     }
     return true;
@@ -419,15 +420,15 @@ TemporaryDir::TemporaryDir()
 {
 }
 
-QString TemporaryDir::createFile(const QByteArray &relativePath, const QByteArray &contents)
+FilePath TemporaryDir::createFile(const QByteArray &relativePath, const QByteArray &contents)
 {
     const QString relativePathString = QString::fromUtf8(relativePath);
     if (relativePathString.isEmpty() || QFileInfo(relativePathString).isAbsolute())
-        return QString();
+        return {};
 
-    const QString filePath = m_temporaryDir.filePath(relativePathString).path();
+    const FilePath filePath = m_temporaryDir.filePath(relativePathString);
     if (!TestCase::writeFile(filePath, contents))
-        return QString();
+        return {};
     return filePath;
 }
 
diff --git a/src/plugins/cppeditor/cpptoolstestcase.h b/src/plugins/cppeditor/cpptoolstestcase.h
index 600075463d1..53284f38be2 100644
--- a/src/plugins/cppeditor/cpptoolstestcase.h
+++ b/src/plugins/cppeditor/cpptoolstestcase.h
@@ -60,7 +60,7 @@ public:
     QString baseDirectory() const { return m_baseDirectory; }
     void setBaseDirectory(const QString &baseDirectory) { m_baseDirectory = baseDirectory; }
 
-    QString filePath() const;
+    Utils::FilePath filePath() const;
     bool writeToDisk() const;
 
     bool hasCursorMarker() const { return m_cursorPosition != -1; }
@@ -123,14 +123,14 @@ public:
     ~TestCase();
 
     bool succeededSoFar() const;
-    static bool openCppEditor(const QString &fileName, TextEditor::BaseTextEditor **editor,
+    static bool openCppEditor(const Utils::FilePath &filePath, TextEditor::BaseTextEditor **editor,
                               CppEditorWidget **editorWidget = nullptr);
     void closeEditorAtEndOfTestCase(Core::IEditor *editor);
 
     static bool closeEditorWithoutGarbageCollectorInvocation(Core::IEditor *editor);
 
     static bool parseFiles(const QString &filePath);
-    static bool parseFiles(const QSet<QString> &filePaths);
+    static bool parseFiles(const QSet<Utils::FilePath> &filePaths);
 
     static CPlusPlus::Snapshot globalSnapshot();
     static bool garbageCollectGlobalSnapshot();
@@ -149,7 +149,7 @@ public:
             const QStringList &filePaths,
             int timeOutInMs = defaultTimeOutInMs);
 
-    static bool writeFile(const QString &filePath, const QByteArray &contents);
+    static bool writeFile(const Utils::FilePath &filePath, const QByteArray &contents);
 
 protected:
     CppModelManager *m_modelManager;
@@ -184,8 +184,9 @@ public:
 
     bool isValid() const { return m_isValid; }
     QString path() const { return m_temporaryDir.path().path(); }
+    Utils::FilePath filePath() const { return m_temporaryDir.path(); }
 
-    QString createFile(const QByteArray &relativePath, const QByteArray &contents);
+    Utils::FilePath createFile(const QByteArray &relativePath, const QByteArray &contents);
 
 protected:
     Utils::TemporaryDirectory m_temporaryDir;
diff --git a/src/plugins/cppeditor/fileandtokenactions_test.cpp b/src/plugins/cppeditor/fileandtokenactions_test.cpp
index 0b781168bdc..c5602c5f678 100644
--- a/src/plugins/cppeditor/fileandtokenactions_test.cpp
+++ b/src/plugins/cppeditor/fileandtokenactions_test.cpp
@@ -51,6 +51,7 @@
 using namespace Core;
 using namespace CPlusPlus;
 using namespace TextEditor;
+using namespace Utils;
 
 namespace CppEditor::Internal::Tests {
 
@@ -158,7 +159,7 @@ TestActionsTestCase::TestActionsTestCase(const Actions &tokenActions, const Acti
         QCOMPARE(DocumentModel::openedDocuments().size(), 0);
         BaseTextEditor *editor;
         CppEditorWidget *editorWidget;
-        QVERIFY(openCppEditor(filePath, &editor, &editorWidget));
+        QVERIFY(openCppEditor(FilePath::fromString(filePath), &editor, &editorWidget));
 
         QCOMPARE(DocumentModel::openedDocuments().size(), 1);
         QVERIFY(m_modelManager->isCppEditor(editor));
diff --git a/src/plugins/cppeditor/followsymbol_switchmethoddecldef_test.cpp b/src/plugins/cppeditor/followsymbol_switchmethoddecldef_test.cpp
index 38cd0cdebcf..c15995504eb 100644
--- a/src/plugins/cppeditor/followsymbol_switchmethoddecldef_test.cpp
+++ b/src/plugins/cppeditor/followsymbol_switchmethoddecldef_test.cpp
@@ -62,6 +62,7 @@ using namespace CPlusPlus;
 using namespace TextEditor;
 using namespace Core;
 using namespace ProjectExplorer;
+using namespace Utils;
 
 class OverrideItem
 {
@@ -256,7 +257,8 @@ F2TestCase::F2TestCase(CppEditorAction action,
         QVERIFY(testFile->baseDirectory().isEmpty());
         testFile->setBaseDirectory(temporaryDir.path());
         QVERIFY(testFile->writeToDisk());
-        projectFileContent += QString::fromLatin1("\"%1\",").arg(testFile->filePath());
+        projectFileContent += QString::fromLatin1("\"%1\",")
+                .arg(testFile->filePath().toString());
     }
     projectFileContent += "]}\n";
 
@@ -272,9 +274,7 @@ F2TestCase::F2TestCase(CppEditorAction action,
         CppTestDocument projectFile("project.qbs", projectFileContent.toUtf8());
         projectFile.setBaseDirectory(temporaryDir.path());
         QVERIFY(projectFile.writeToDisk());
-        const auto openProjectResult =
-                ProjectExplorerPlugin::openProject(
-                    Utils::FilePath::fromString(projectFile.filePath()));
+        const auto openProjectResult = ProjectExplorerPlugin::openProject(projectFile.filePath());
         QVERIFY2(openProjectResult && openProjectResult.project(),
                  qPrintable(openProjectResult.errorMessage()));
         projectCloser.setProject(openProjectResult.project());
@@ -286,7 +286,7 @@ F2TestCase::F2TestCase(CppEditorAction action,
     }
 
     // Update Code Model
-    QSet<QString> filePaths;
+    QSet<FilePath> filePaths;
    for (const TestDocumentPtr &testFile : testFiles)
         filePaths << testFile->filePath();
     QVERIFY(parseFiles(filePaths));
@@ -302,7 +302,8 @@ F2TestCase::F2TestCase(CppEditorAction action,
         // The file is "Full Checked" since it is in the working copy now,
         // that is the function bodies are processed.
         forever {
-            const Document::Ptr document = waitForFileInGlobalSnapshot(testFile->filePath());
+            const Document::Ptr document =
+                    waitForFileInGlobalSnapshot(testFile->filePath().toString());
             QVERIFY(document);
             if (document->checkMode() == Document::FullCheck) {
                 if (!document->diagnosticMessages().isEmpty())
@@ -405,7 +406,7 @@ F2TestCase::F2TestCase(CppEditorAction action,
     BaseTextEditor *currentTextEditor = dynamic_cast<BaseTextEditor*>(currentEditor);
     QVERIFY(currentTextEditor);
 
-    QCOMPARE(currentTextEditor->document()->filePath().toString(), targetTestFile->filePath());
+    QCOMPARE(currentTextEditor->document()->filePath(), targetTestFile->filePath());
     int expectedLine, expectedColumn;
     if (useClangd && expectedVirtualFunctionProposal.size() == 1) {
         expectedLine = expectedVirtualFunctionProposal.first().line;
diff --git a/src/plugins/cppeditor/includeutils.cpp b/src/plugins/cppeditor/includeutils.cpp
index cf855f154f8..f79bb8db127 100644
--- a/src/plugins/cppeditor/includeutils.cpp
+++ b/src/plugins/cppeditor/includeutils.cpp
@@ -518,7 +518,7 @@ static QList<Include> includesForSource(const QString &filePath)
                                      TestIncludePaths::globalIncludePath())});
     sourceProcessor->run(filePath);
 
-    Document::Ptr document = cmm->document(filePath);
+    Document::Ptr document = cmm->document(FilePath::fromString(filePath));
     return document->resolvedIncludes();
 }
 
diff --git a/src/plugins/cppeditor/insertionpointlocator.cpp b/src/plugins/cppeditor/insertionpointlocator.cpp
index 4479246f611..a0aa777cc64 100644
--- a/src/plugins/cppeditor/insertionpointlocator.cpp
+++ b/src/plugins/cppeditor/insertionpointlocator.cpp
@@ -251,13 +251,12 @@ InsertionPointLocator::InsertionPointLocator(const CppRefactoringChanges &refact
 }
 
 InsertionLocation InsertionPointLocator::methodDeclarationInClass(
-    const QString &fileName,
+    const Utils::FilePath &filePath,
     const Class *clazz,
     AccessSpec xsSpec,
     ForceAccessSpec forceAccessSpec) const
 {
-    const Document::Ptr doc = m_refactoringChanges.file(Utils::FilePath::fromString(fileName))
-                                  ->cppDocument();
+    const Document::Ptr doc = m_refactoringChanges.file(filePath)->cppDocument();
     if (doc) {
         FindInClass find(doc->translationUnit(), clazz);
         ClassSpecifierAST *classAST = find();
diff --git a/src/plugins/cppeditor/insertionpointlocator.h b/src/plugins/cppeditor/insertionpointlocator.h
index b9133e67e20..8dc5f561a70 100644
--- a/src/plugins/cppeditor/insertionpointlocator.h
+++ b/src/plugins/cppeditor/insertionpointlocator.h
@@ -80,8 +80,7 @@ public:
 public:
     explicit InsertionPointLocator(const CppRefactoringChanges &refactoringChanges);
 
-    InsertionLocation methodDeclarationInClass(
-            const QString &fileName,
+    InsertionLocation methodDeclarationInClass(const Utils::FilePath &fileName,
             const CPlusPlus::Class *clazz,
             AccessSpec xsSpec,
             ForceAccessSpec forceAccessSpec = ForceAccessSpec::No
diff --git a/src/plugins/cppeditor/searchsymbols.cpp b/src/plugins/cppeditor/searchsymbols.cpp
index 0fa87c4b11b..6eb143a276c 100644
--- a/src/plugins/cppeditor/searchsymbols.cpp
+++ b/src/plugins/cppeditor/searchsymbols.cpp
@@ -37,7 +37,7 @@ void SearchSymbols::setSymbolsToSearchFor(const SymbolTypes &types)
 
 IndexItem::Ptr SearchSymbols::operator()(Document::Ptr doc, const QString &scope)
 {
-    IndexItem::Ptr root = IndexItem::create(Internal::StringTable::insert(doc->fileName()), 100);
+    IndexItem::Ptr root = IndexItem::create(Internal::StringTable::insert(doc->filePath()), 100);
 
     { // RAII scope
         ScopedIndexItemPtr parentRaii(_parent, root);
@@ -46,7 +46,7 @@ IndexItem::Ptr SearchSymbols::operator()(Document::Ptr doc, const QString &scope
 
         QTC_ASSERT(_parent, return IndexItem::Ptr());
         QTC_ASSERT(root, return IndexItem::Ptr());
-        QTC_ASSERT(_parent->fileName() == Internal::StringTable::insert(doc->fileName()),
+        QTC_ASSERT(_parent->fileName() == Internal::StringTable::insert(doc->filePath()),
                    return IndexItem::Ptr());
 
         for (int i = 0, ei = doc->globalSymbolCount(); i != ei; ++i)
diff --git a/src/plugins/cppeditor/stringtable.cpp b/src/plugins/cppeditor/stringtable.cpp
index 6f0ef89b18a..64f324ad36f 100644
--- a/src/plugins/cppeditor/stringtable.cpp
+++ b/src/plugins/cppeditor/stringtable.cpp
@@ -56,6 +56,11 @@ StringTablePrivate::StringTablePrivate()
     connect(&m_gcCountDown, &QTimer::timeout, this, &StringTablePrivate::startGC);
 }
 
+QString StringTable::insert(const Utils::FilePath &path)
+{
+    return m_instance->insert(path.path());
+}
+
 QString StringTable::insert(const QString &string)
 {
     return m_instance->insert(string);
diff --git a/src/plugins/cppeditor/stringtable.h b/src/plugins/cppeditor/stringtable.h
index d24d77c02e0..675d3f6539b 100644
--- a/src/plugins/cppeditor/stringtable.h
+++ b/src/plugins/cppeditor/stringtable.h
@@ -3,13 +3,14 @@
 
 #pragma once
 
-#include <QString>
+#include <utils/filepath.h>
 
 namespace CppEditor::Internal {
 
 class StringTable
 {
 public:
+    static QString insert(const Utils::FilePath &string);
     static QString insert(const QString &string);
     static void scheduleGC();
 
diff --git a/src/plugins/cppeditor/symbolfinder.cpp b/src/plugins/cppeditor/symbolfinder.cpp
index df93d36246d..484dfd6e1b2 100644
--- a/src/plugins/cppeditor/symbolfinder.cpp
+++ b/src/plugins/cppeditor/symbolfinder.cpp
@@ -444,7 +444,7 @@ QStringList SymbolFinder::fileIterationOrder(const QString &referenceFile, const
         checkCacheConsistency(referenceFile, snapshot);
     } else {
         for (Document::Ptr doc : snapshot)
-            insertCache(referenceFile, doc->fileName());
+            insertCache(referenceFile, doc->filePath().path());
     }
 
     QStringList files = m_filePriorityCache.value(referenceFile).toStringList();
@@ -468,8 +468,8 @@ void SymbolFinder::checkCacheConsistency(const QString &referenceFile, const Sna
     // corresponding document and notices it's now null.
     const QSet<QString> &meta = m_fileMetaCache.value(referenceFile);
     for (const Document::Ptr &doc : snapshot) {
-        if (!meta.contains(doc->fileName()))
-            insertCache(referenceFile, doc->fileName());
+        if (!meta.contains(doc->filePath().path()))
+            insertCache(referenceFile, doc->filePath().path());
     }
 }
 
diff --git a/src/plugins/cppeditor/typehierarchybuilder_test.cpp b/src/plugins/cppeditor/typehierarchybuilder_test.cpp
index c1509df12f6..095aba97eaf 100644
--- a/src/plugins/cppeditor/typehierarchybuilder_test.cpp
+++ b/src/plugins/cppeditor/typehierarchybuilder_test.cpp
@@ -16,6 +16,8 @@
 #include <QtTest>
 
 using namespace CPlusPlus;
+using namespace Utils;
+
 using CppEditor::Internal::Tests::CppTestDocument;
 
 Q_DECLARE_METATYPE(QList<CppTestDocument>)
@@ -82,7 +84,7 @@ public:
         QList<CppTestDocument> documents_ = documents;
 
         // Write files
-        QSet<QString> filePaths;
+        QSet<FilePath> filePaths;
         for (auto &document : documents_) {
             document.setBaseDirectory(temporaryDir.path());
             QVERIFY(document.writeToDisk());
diff --git a/src/plugins/designer/qtcreatorintegration.cpp b/src/plugins/designer/qtcreatorintegration.cpp
index e889e212222..e3c0cc4e067 100644
--- a/src/plugins/designer/qtcreatorintegration.cpp
+++ b/src/plugins/designer/qtcreatorintegration.cpp
@@ -52,7 +52,7 @@ static QString msgClassNotFound(const QString &uiClassName, const QList<Document
     QString files;
     for (const Document::Ptr &doc : docList) {
         files += '\n';
-        files += QDir::toNativeSeparators(doc->fileName());
+        files += doc->filePath().toUserOutput();
     }
     return Designer::Tr::tr(
         "The class containing \"%1\" could not be found in %2.\n"
@@ -241,7 +241,7 @@ static void addDeclaration(const Snapshot &snapshot,
     CppEditor::CppRefactoringChanges refactoring(snapshot);
     CppEditor::InsertionPointLocator find(refactoring);
     const CppEditor::InsertionLocation loc = find.methodDeclarationInClass(
-                fileName, cl, CppEditor::InsertionPointLocator::PrivateSlot);
+                FilePath::fromString(fileName), cl, CppEditor::InsertionPointLocator::PrivateSlot);
 
     //
     //! \todo change this to use the Refactoring changes.
@@ -339,7 +339,7 @@ static ClassDocumentPtrPair
     const Document::Ptr doc = context.thisDocument();
     const Snapshot docTable = context.snapshot();
     if (Designer::Constants::Internal::debug)
-        qDebug() << Q_FUNC_INFO << doc->fileName() << className << maxIncludeDepth;
+        qDebug() << Q_FUNC_INFO << doc->filePath() << className << maxIncludeDepth;
     // Check document
     if (const Class *cl = findClass(doc->globalNamespace(), context, className))
         return ClassDocumentPtrPair(cl, doc);
@@ -455,8 +455,8 @@ bool QtCreatorIntegration::navigateToSlot(const QString &objectName,
     const QList<Document::Ptr> docList = findDocumentsIncluding(docTable, uicedName, true); // change to false when we know the absolute path to generated ui_<>.h file
     DocumentMap docMap;
     for (const Document::Ptr &d : docList) {
-        const QFileInfo docFi(d->fileName());
-        docMap.insert(qAbs(docFi.absolutePath().compare(uiFolder, Qt::CaseInsensitive)), d);
+        docMap.insert(qAbs(d->filePath().absolutePath().toString()
+                           .compare(uiFolder, Qt::CaseInsensitive)), d);
     }
 
     if (Designer::Constants::Internal::debug)
@@ -501,14 +501,14 @@ bool QtCreatorIntegration::navigateToSlot(const QString &objectName,
     const QString functionNameWithParameterNames = addParameterNames(functionName, parameterNames);
 
     if (Designer::Constants::Internal::debug)
-        qDebug() << Q_FUNC_INFO << "Found " << uiClass << declDoc->fileName() << " checking " << functionName  << functionNameWithParameterNames;
+        qDebug() << Q_FUNC_INFO << "Found " << uiClass << declDoc->filePath() << " checking " << functionName  << functionNameWithParameterNames;
 
     Function *fun = findDeclaration(cl, functionName);
     QString declFilePath;
     if (!fun) {
         // add function declaration to cl
         CppEditor::WorkingCopy workingCopy = CppEditor::CppModelManager::instance()->workingCopy();
-        declFilePath = declDoc->fileName();
+        declFilePath = declDoc->filePath().toString();
         getParsedDocument(declFilePath, workingCopy, docTable);
         addDeclaration(docTable, declFilePath, cl, functionNameWithParameterNames);
 
diff --git a/src/plugins/todo/cpptodoitemsscanner.cpp b/src/plugins/todo/cpptodoitemsscanner.cpp
index 47a020ff4fc..3a8db09456f 100644
--- a/src/plugins/todo/cpptodoitemsscanner.cpp
+++ b/src/plugins/todo/cpptodoitemsscanner.cpp
@@ -46,7 +46,7 @@ void CppTodoItemsScanner::scannerParamsChanged()
 void CppTodoItemsScanner::documentUpdated(CPlusPlus::Document::Ptr doc)
 {
     CppEditor::CppModelManager *modelManager = CppEditor::CppModelManager::instance();
-    if (!modelManager->projectPart(doc->fileName()).isEmpty())
+    if (!modelManager->projectPart(doc->filePath()).isEmpty())
         processDocument(doc);
 }
 
@@ -84,13 +84,13 @@ void CppTodoItemsScanner::processDocument(CPlusPlus::Document::Ptr doc)
             const int length = end - start + 1;
             if (length > 0) {
                 QString commentLine = QString::fromUtf8(start, length);
-                processCommentLine(doc->fileName(), commentLine, lineNumber, itemList);
+                processCommentLine(doc->filePath().toString(), commentLine, lineNumber, itemList);
             }
 
             from = to + 1;
         }
     }
-    emit itemsFetched(doc->fileName(), itemList);
+    emit itemsFetched(doc->filePath().toString(), itemList);
 }
 
 }