diff --git a/Makefile b/Makefile
index 3fef3103d96..e10ddfbcede 100644
--- a/Makefile
+++ b/Makefile
@@ -649,7 +649,7 @@ $(libcppdir)/settings.o: lib/settings.cpp externals/picojson/picojson.h lib/addo
 $(libcppdir)/standards.o: lib/standards.cpp externals/simplecpp/simplecpp.h lib/config.h lib/standards.h lib/utils.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(libcppdir)/standards.cpp
 
-$(libcppdir)/summaries.o: lib/summaries.cpp lib/addoninfo.h lib/analyzerinfo.h lib/checkers.h lib/config.h lib/errortypes.h lib/library.h lib/mathlib.h lib/platform.h lib/settings.h lib/smallvector.h lib/sourcelocation.h lib/standards.h lib/summaries.h lib/symboldatabase.h lib/templatesimplifier.h lib/token.h lib/tokenize.h lib/tokenlist.h lib/utils.h lib/vfvalue.h
+$(libcppdir)/summaries.o: lib/summaries.cpp lib/addoninfo.h lib/analyzerinfo.h lib/checkers.h lib/config.h lib/errortypes.h lib/library.h lib/mathlib.h lib/path.h lib/platform.h lib/settings.h lib/smallvector.h lib/sourcelocation.h lib/standards.h lib/summaries.h lib/symboldatabase.h lib/templatesimplifier.h lib/token.h lib/tokenize.h lib/tokenlist.h lib/utils.h lib/vfvalue.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(libcppdir)/summaries.cpp
 
 $(libcppdir)/suppressions.o: lib/suppressions.cpp externals/tinyxml2/tinyxml2.h lib/config.h lib/errorlogger.h lib/errortypes.h lib/filesettings.h lib/mathlib.h lib/path.h lib/pathmatch.h lib/platform.h lib/smallvector.h lib/standards.h lib/suppressions.h lib/templatesimplifier.h lib/token.h lib/tokenize.h lib/tokenlist.h lib/utils.h lib/vfvalue.h lib/xml.h
diff --git a/gui/checkthread.cpp b/gui/checkthread.cpp
index 090b698a6e7..e2cbd77dc51 100644
--- a/gui/checkthread.cpp
+++ b/gui/checkthread.cpp
@@ -238,7 +238,7 @@ void CheckThread::runAddonsAndTools(const Settings& settings, const FileSettings
 
             const std::string &buildDir = settings.buildDir;
             if (!buildDir.empty()) {
-                analyzerInfoFile = QString::fromStdString(AnalyzerInformation::getAnalyzerInfoFile(buildDir, fileSettings->filename(), fileSettings->cfg, fileSettings->fileIndex));
+                analyzerInfoFile = QString::fromStdString(AnalyzerInformation::getAnalyzerInfoFile(buildDir, fileSettings->sfilename(), fileSettings->cfg, fileSettings->file.fsFileId()));
 
                 QStringList args2(args);
                 args2.insert(0,"-E");
diff --git a/lib/analyzerinfo.cpp b/lib/analyzerinfo.cpp
index 6d5ac9a9b15..a278ad76ee6 100644
--- a/lib/analyzerinfo.cpp
+++ b/lib/analyzerinfo.cpp
@@ -69,7 +69,7 @@ std::string AnalyzerInformation::getFilesTxt(const std::list<std::string> &sourc
 
     for (const FileSettings &fs : fileSettings) {
         const std::string afile = getFilename(fs.filename());
-        const std::string id = fs.fileIndex > 0 ? std::to_string(fs.fileIndex) : "";
+        const std::string id = fs.file.fsFileId() > 0 ? std::to_string(fs.file.fsFileId()) : "";
         ret << afile << ".a" << (++fileCount[afile]) << sep << fs.cfg << sep << id << sep << Path::simplifyPath(fs.filename()) << std::endl;
     }
 
@@ -128,11 +128,11 @@ std::string AnalyzerInformation::getAnalyzerInfoFileFromFilesTxt(std::istream& f
     return "";
 }
 
-std::string AnalyzerInformation::getAnalyzerInfoFile(const std::string &buildDir, const std::string &sourcefile, const std::string &cfg, int fileIndex)
+std::string AnalyzerInformation::getAnalyzerInfoFile(const std::string &buildDir, const std::string &sourcefile, const std::string &cfg, std::size_t fsFileId)
 {
     std::ifstream fin(Path::join(buildDir, "files.txt"));
     if (fin.is_open()) {
-        const std::string& ret = getAnalyzerInfoFileFromFilesTxt(fin, sourcefile, cfg, fileIndex);
+        const std::string& ret = getAnalyzerInfoFileFromFilesTxt(fin, sourcefile, cfg, fsFileId);
         if (!ret.empty())
             return Path::join(buildDir, ret);
     }
@@ -146,13 +146,13 @@ std::string AnalyzerInformation::getAnalyzerInfoFile(const std::string &buildDir
     return Path::join(buildDir, std::move(filename)) + ".analyzerinfo";
 }
 
-bool AnalyzerInformation::analyzeFile(const std::string &buildDir, const std::string &sourcefile, const std::string &cfg, int fileIndex, std::size_t hash, std::list<ErrorMessage> &errors)
+bool AnalyzerInformation::analyzeFile(const std::string &buildDir, const std::string &sourcefile, const std::string &cfg, std::size_t fsFileId, std::size_t hash, std::list<ErrorMessage> &errors)
 {
     if (buildDir.empty() || sourcefile.empty())
         return true;
     close();
 
-    mAnalyzerInfoFile = AnalyzerInformation::getAnalyzerInfoFile(buildDir,sourcefile,cfg,fileIndex);
+    mAnalyzerInfoFile = AnalyzerInformation::getAnalyzerInfoFile(buildDir,sourcefile,cfg,fsFileId);
 
     tinyxml2::XMLDocument analyzerInfoDoc;
     const tinyxml2::XMLError xmlError = analyzerInfoDoc.LoadFile(mAnalyzerInfoFile.c_str());
@@ -194,10 +194,10 @@ bool AnalyzerInformation::Info::parse(const std::string& filesTxtLine) {
         return false;
 
     if (sep3 == sep2 + 1)
-        fileIndex = 0;
+        fsFileId = 0;
     else {
         try {
-            fileIndex = std::stoi(filesTxtLine.substr(sep2+1, sep3-sep2-1));
+            fsFileId = std::stoi(filesTxtLine.substr(sep2+1, sep3-sep2-1));
         } catch (const std::exception&) {
             return false;
         }
diff --git a/lib/analyzerinfo.h b/lib/analyzerinfo.h
index 04ea1a5b339..d28a82c514c 100644
--- a/lib/analyzerinfo.h
+++ b/lib/analyzerinfo.h
@@ -61,10 +61,10 @@ class CPPCHECKLIB AnalyzerInformation {
 
     /** Close current TU.analyzerinfo file */
     void close();
-    bool analyzeFile(const std::string &buildDir, const std::string &sourcefile, const std::string &cfg, int fileIndex, std::size_t hash, std::list<ErrorMessage> &errors);
+    bool analyzeFile(const std::string &buildDir, const std::string &sourcefile, const std::string &cfg, std::size_t fsFileId, std::size_t hash, std::list<ErrorMessage> &errors);
     void reportErr(const ErrorMessage &msg);
     void setFileInfo(const std::string &check, const std::string &fileInfo);
-    static std::string getAnalyzerInfoFile(const std::string &buildDir, const std::string &sourcefile, const std::string &cfg, int fileIndex);
+    static std::string getAnalyzerInfoFile(const std::string &buildDir, const std::string &sourcefile, const std::string &cfg, std::size_t fsFileId);
 
     static const char sep = ':';
 
@@ -73,7 +73,7 @@ class CPPCHECKLIB AnalyzerInformation {
         bool parse(const std::string& filesTxtLine);
         std::string afile;
         std::string cfg;
-        int fileIndex = 0;
+        std::size_t fsFileId = 0;
         std::string sourceFile;
     };
 
diff --git a/lib/cppcheck.cpp b/lib/cppcheck.cpp
index c7c6ea65dfc..615ddd4e213 100644
--- a/lib/cppcheck.cpp
+++ b/lib/cppcheck.cpp
@@ -332,17 +332,17 @@ static std::vector<std::string> split(const std::string &str, const std::string
     return ret;
 }
 
-static std::string getDumpFileName(const Settings& settings, const std::string& filename, int fileIndex)
+static std::string getDumpFileName(const Settings& settings, const FileWithDetails& file)
 {
     std::string extension = ".dump";
-    if (fileIndex > 0)
-        extension = "." + std::to_string(fileIndex) + extension;
+    if (file.fsFileId() > 0)
+        extension = "." + std::to_string(file.fsFileId()) + extension;
     if (!settings.dump && settings.buildDir.empty())
         extension = "." + std::to_string(settings.pid) + extension;
 
     if (!settings.dump && !settings.buildDir.empty())
-        return AnalyzerInformation::getAnalyzerInfoFile(settings.buildDir, filename, "", fileIndex) + extension;
-    return filename + extension;
+        return AnalyzerInformation::getAnalyzerInfoFile(settings.buildDir, file.spath(), "", file.fsFileId()) + extension;
+    return file.spath() + extension;
 }
 
 static std::string getCtuInfoFileName(const std::string &dumpFile)
@@ -352,13 +352,12 @@ static std::string getCtuInfoFileName(const std::string &dumpFile)
 
 static void createDumpFile(const Settings& settings,
                            const FileWithDetails& file,
-                           int fileIndex,
                            std::ofstream& fdump,
                            std::string& dumpFile)
 {
     if (!settings.dump && settings.addons.empty())
         return;
-    dumpFile = getDumpFileName(settings, file.spath(), fileIndex);
+    dumpFile = getDumpFileName(settings, file);
 
     fdump.open(dumpFile);
     if (!fdump.is_open())
@@ -660,7 +659,7 @@ static std::string getClangFlags(const Settings& setting, Standards::Language la
 }
 
 // TODO: clear error list before returning
-unsigned int CppCheck::checkClang(const FileWithDetails &file, int fileIndex)
+unsigned int CppCheck::checkClang(const FileWithDetails &file)
 {
     // TODO: clear exitcode
 
@@ -673,7 +672,7 @@ unsigned int CppCheck::checkClang(const FileWithDetails &file, int fileIndex)
     // TODO: get language from FileWithDetails object
     std::string clangStderr;
     if (!mSettings.buildDir.empty())
-        clangStderr = AnalyzerInformation::getAnalyzerInfoFile(mSettings.buildDir, file.spath(), "", fileIndex) + ".clang-stderr";
+        clangStderr = AnalyzerInformation::getAnalyzerInfoFile(mSettings.buildDir, file.spath(), "", file.fsFileId()) + ".clang-stderr";
 
     std::string exe = mSettings.clangExecutable;
 #ifdef _WIN32
@@ -747,7 +746,7 @@ unsigned int CppCheck::checkClang(const FileWithDetails &file, int fileIndex)
         // create dumpfile
         std::ofstream fdump;
         std::string dumpFile;
-        createDumpFile(mSettings, file, fileIndex, fdump, dumpFile);
+        createDumpFile(mSettings, file, fdump, dumpFile);
         if (fdump.is_open()) {
             fdump << getLibraryDumpData();
             // TODO: use tinyxml2 to create XML
@@ -791,9 +790,9 @@ unsigned int CppCheck::check(const FileWithDetails &file)
 
     unsigned int returnValue;
     if (mSettings.clang)
-        returnValue = checkClang(file, 0);
+        returnValue = checkClang(file);
     else
-        returnValue = checkFile(file, "", 0);
+        returnValue = checkFile(file, "");
 
     // TODO: call analyseClangTidy()
 
@@ -802,7 +801,7 @@ unsigned int CppCheck::check(const FileWithDetails &file)
 
 unsigned int CppCheck::checkBuffer(const FileWithDetails &file, const char* data, std::size_t size)
 {
-    return checkBuffer(file, "", 0, data, size);
+    return checkBuffer(file, "", data, size);
 }
 
 unsigned int CppCheck::check(const FileSettings &fs)
@@ -838,7 +837,7 @@ unsigned int CppCheck::check(const FileSettings &fs)
     }
     // need to pass the externally provided ErrorLogger instead of our internal wrapper
     CppCheck temp(tempSettings, mSuppressions, mErrorLoggerDirect, mUseGlobalSuppressions, mExecuteCommand);
-    const unsigned int returnValue = temp.checkFile(fs.file, fs.cfg, fs.fileIndex);
+    const unsigned int returnValue = temp.checkFile(fs.file, fs.cfg);
     if (mUnusedFunctionsCheck)
         mUnusedFunctionsCheck->updateFunctionData(*temp.mUnusedFunctionsCheck);
     while (!temp.mFileInfo.empty()) {
@@ -875,20 +874,20 @@ std::size_t CppCheck::calculateHash(const Preprocessor& preprocessor, const std:
     return preprocessor.calculateHash(toolinfo.str());
 }
 
-unsigned int CppCheck::checkBuffer(const FileWithDetails &file, const std::string &cfgname, int fileIndex, const char* data, std::size_t size)
+unsigned int CppCheck::checkBuffer(const FileWithDetails &file, const std::string &cfgname, const char* data, std::size_t size)
 {
     const auto f = [&file, data, size](std::vector<std::string>& files, simplecpp::OutputList* outputList) {
         return simplecpp::TokenList{{data, size}, files, file.spath(), outputList};
     };
-    return checkInternal(file, cfgname, fileIndex, f);
+    return checkInternal(file, cfgname, f);
 }
 
-unsigned int CppCheck::checkFile(const FileWithDetails& file, const std::string &cfgname, int fileIndex)
+unsigned int CppCheck::checkFile(const FileWithDetails& file, const std::string &cfgname)
 {
     const auto f = [&file](std::vector<std::string>& files, simplecpp::OutputList* outputList) {
         return simplecpp::TokenList{file.spath(), files, outputList};
     };
-    return checkInternal(file, cfgname, fileIndex, f);
+    return checkInternal(file, cfgname, f);
 }
 
 void CppCheck::checkPlistOutput(const FileWithDetails& file, const std::vector<std::string>& files)
@@ -906,7 +905,7 @@ void CppCheck::checkPlistOutput(const FileWithDetails& file, const std::vector<s
     }
 }
 
-unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::string &cfgname, int fileIndex, const CreateTokenListFn& createTokenList)
+unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::string &cfgname, const CreateTokenListFn& createTokenList)
 {
     // TODO: move to constructor when CppCheck no longer owns the settings
     if (mSettings.checks.isEnabled(Checks::unusedFunction) && !mUnusedFunctionsCheck)
@@ -974,7 +973,7 @@ unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::str
                     mLogger->setAnalyzerInfo(nullptr);
 
                     std::list<ErrorMessage> errors;
-                    analyzerInformation->analyzeFile(mSettings.buildDir, file.spath(), cfgname, fileIndex, hash, errors);
+                    analyzerInformation->analyzeFile(mSettings.buildDir, file.spath(), cfgname, file.fsFileId(), hash, errors);
                     analyzerInformation->setFileInfo("CheckUnusedFunctions", mUnusedFunctionsCheck->analyzerInfo(tokenizer));
                     analyzerInformation->close();
                 }
@@ -1020,7 +1019,7 @@ unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::str
             // Calculate hash so it can be compared with old hash / future hashes
             const std::size_t hash = calculateHash(preprocessor, file.spath());
             std::list<ErrorMessage> errors;
-            if (!analyzerInformation->analyzeFile(mSettings.buildDir, file.spath(), cfgname, fileIndex, hash, errors)) {
+            if (!analyzerInformation->analyzeFile(mSettings.buildDir, file.spath(), cfgname, file.fsFileId(), hash, errors)) {
                 while (!errors.empty()) {
                     mErrorLogger.reportErr(errors.front());
                     errors.pop_front();
@@ -1077,7 +1076,7 @@ unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::str
         // write dump file xml prolog
         std::ofstream fdump;
         std::string dumpFile;
-        createDumpFile(mSettings, file, fileIndex, fdump, dumpFile);
+        createDumpFile(mSettings, file, fdump, dumpFile);
         if (fdump.is_open()) {
             fdump << getLibraryDumpData();
             fdump << dumpProlog;
@@ -1201,7 +1200,7 @@ unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::str
 #endif
 
                     // Simplify tokens into normal form, skip rest of iteration if failed
-                    if (!tokenizer.simplifyTokens1(currentConfig, fileIndex))
+                    if (!tokenizer.simplifyTokens1(currentConfig, file.fsFileId()))
                         continue;
 
                     // dump xml if --dump
@@ -1641,12 +1640,12 @@ void CppCheck::executeAddonsWholeProgram(const std::list<FileWithDetails> &files
 
     std::vector<std::string> ctuInfoFiles;
     for (const auto &f: files) {
-        const std::string &dumpFileName = getDumpFileName(mSettings, f.path(), 0);
+        const std::string &dumpFileName = getDumpFileName(mSettings, f);
         ctuInfoFiles.push_back(getCtuInfoFileName(dumpFileName));
     }
 
-    for (const auto &f: fileSettings) {
-        const std::string &dumpFileName = getDumpFileName(mSettings, f.filename(), f.fileIndex);
+    for (const auto &fs: fileSettings) {
+        const std::string &dumpFileName = getDumpFileName(mSettings, fs.file);
         ctuInfoFiles.push_back(getCtuInfoFileName(dumpFileName));
     }
 
@@ -1758,7 +1757,7 @@ void CppCheck::analyseClangTidy(const FileSettings &fileSettings)
     std::string line;
 
     if (!mSettings.buildDir.empty()) {
-        const std::string analyzerInfoFile = AnalyzerInformation::getAnalyzerInfoFile(mSettings.buildDir, fileSettings.filename(), "", fileSettings.fileIndex);
+        const std::string analyzerInfoFile = AnalyzerInformation::getAnalyzerInfoFile(mSettings.buildDir, fileSettings.sfilename(), "", fileSettings.file.fsFileId());
         std::ofstream fcmd(analyzerInfoFile + ".clang-tidy-cmd");
         fcmd << istr.str();
     }
diff --git a/lib/cppcheck.h b/lib/cppcheck.h
index 44286c294d2..06d0a992577 100644
--- a/lib/cppcheck.h
+++ b/lib/cppcheck.h
@@ -182,7 +182,7 @@ class CPPCHECKLIB CppCheck {
      * @param cfgname  cfg name
      * @return number of errors found
      */
-    unsigned int checkFile(const FileWithDetails& file, const std::string &cfgname, int fileIndex);
+    unsigned int checkFile(const FileWithDetails& file, const std::string &cfgname);
 
     void checkPlistOutput(const FileWithDetails& file, const std::vector<std::string>& files);
 
@@ -194,7 +194,7 @@ class CPPCHECKLIB CppCheck {
      * @param size the size of the data to be read
      * @return number of errors found
      */
-    unsigned int checkBuffer(const FileWithDetails& file, const std::string &cfgname, int fileIndex, const char* data, std::size_t size);
+    unsigned int checkBuffer(const FileWithDetails& file, const std::string &cfgname, const char* data, std::size_t size);
 
     // TODO: should use simplecpp::OutputList
     using CreateTokenListFn = std::function<simplecpp::TokenList (std::vector<std::string>&, std::list<simplecpp::Output>*)>;
@@ -206,7 +206,7 @@ class CPPCHECKLIB CppCheck {
      * @param createTokenList a function to create the simplecpp::TokenList with
      * @return number of errors found
      */
-    unsigned int checkInternal(const FileWithDetails& file, const std::string &cfgname, int fileIndex, const CreateTokenListFn& createTokenList);
+    unsigned int checkInternal(const FileWithDetails& file, const std::string &cfgname, const CreateTokenListFn& createTokenList);
 
     /**
      * @brief Check normal tokens
@@ -235,7 +235,7 @@ class CPPCHECKLIB CppCheck {
     void executeRules(const std::string &tokenlist, const TokenList &list);
 #endif
 
-    unsigned int checkClang(const FileWithDetails &file, int fileIndex);
+    unsigned int checkClang(const FileWithDetails &file);
 
     const Settings& mSettings;
     Suppressions& mSuppressions;
diff --git a/lib/filesettings.h b/lib/filesettings.h
index 3149421c629..5a5ece9366b 100644
--- a/lib/filesettings.h
+++ b/lib/filesettings.h
@@ -35,15 +35,20 @@ class FileWithDetails
 {
 public:
     FileWithDetails(std::string path, Standards::Language lang, std::size_t size)
-        : mPath(std::move(path))
-        , mPathSimplified(Path::simplifyPath(mPath))
-        , mLang(lang)
+        : mLang(lang)
         , mSize(size)
     {
+        setPath(std::move(path));
         if (mPath.empty())
             throw std::runtime_error("empty path specified");
     }
 
+    void setPath(std::string path)
+    {
+        mPath = std::move(path);
+        mPathSimplified = Path::simplifyPath(mPath);
+    }
+
     const std::string& path() const
     {
         return mPath;
@@ -68,11 +73,22 @@ class FileWithDetails
     {
         return mLang;
     }
+
+    std::size_t fsFileId() const
+    {
+        return mFsFileId;
+    }
+
+    void setFsFileId(std::size_t fsFileId)
+    {
+        mFsFileId = fsFileId;
+    }
 private:
     std::string mPath;
     std::string mPathSimplified;
     Standards::Language mLang = Standards::Language::None;
     std::size_t mSize;
+    std::size_t mFsFileId{0};
 };
 
 /** File settings. Multiple configurations for a file is allowed. */
@@ -81,14 +97,12 @@ struct CPPCHECKLIB FileSettings {
         : file(std::move(path), lang, size)
     {}
 
-    int fileIndex = 0;
     std::string cfg;
     FileWithDetails file;
     const std::string& filename() const
     {
         return file.path();
     }
-    // cppcheck-suppress unusedFunction
     const std::string& sfilename() const
     {
         return file.spath();
diff --git a/lib/importproject.cpp b/lib/importproject.cpp
index acd7842224f..dcf0631685d 100644
--- a/lib/importproject.cpp
+++ b/lib/importproject.cpp
@@ -347,7 +347,7 @@ bool ImportProject::importCompileCommands(std::istream &istr)
         return false;
     }
 
-    std::map<std::string, int> fileIndex;
+    std::map<std::string, std::size_t> fsFileIds;
 
     for (const picojson::value &fileInfo : compileCommands.get<picojson::array>()) {
         picojson::object obj = fileInfo.get<picojson::object>();
@@ -430,7 +430,7 @@ bool ImportProject::importCompileCommands(std::istream &istr)
         fsSetIncludePaths(fs, directory, fs.includePaths, variables);
         // Assign a unique index to each file path. If the file path already exists in the map,
         // increment the index to handle duplicate file entries.
-        fs.fileIndex = fileIndex[path]++;
+        fs.file.setFsFileId(fsFileIds[path]++);
         fileSettings.push_back(std::move(fs));
     }
 
@@ -1548,7 +1548,7 @@ void ImportProject::setRelativePaths(const std::string &filename)
         return;
     const std::vector<std::string> basePaths{Path::fromNativeSeparators(Path::getCurrentPath())};
     for (auto &fs: fileSettings) {
-        fs.file = FileWithDetails{Path::getRelativePath(fs.filename(), basePaths), Standards::Language::None, 0}; // file will be identified later on
+        fs.file.setPath(Path::getRelativePath(fs.filename(), basePaths));
         for (auto &includePath: fs.includePaths)
             includePath = Path::getRelativePath(includePath, basePaths);
     }
diff --git a/lib/summaries.cpp b/lib/summaries.cpp
index a543fcc7065..52a5d06b141 100644
--- a/lib/summaries.cpp
+++ b/lib/summaries.cpp
@@ -19,6 +19,7 @@
 #include "summaries.h"
 
 #include "analyzerinfo.h"
+#include "path.h"
 #include "settings.h"
 #include "symboldatabase.h"
 #include "token.h"
@@ -34,7 +35,7 @@
 
 
 
-std::string Summaries::create(const Tokenizer &tokenizer, const std::string &cfg, int fileIndex)
+std::string Summaries::create(const Tokenizer &tokenizer, const std::string &cfg, std::size_t fsFileId)
 {
     const SymbolDatabase *symbolDatabase = tokenizer.getSymbolDatabase();
     const Settings &settings = tokenizer.getSettings();
@@ -82,7 +83,7 @@ std::string Summaries::create(const Tokenizer &tokenizer, const std::string &cfg
     }
 
     if (!settings.buildDir.empty()) {
-        std::string filename = AnalyzerInformation::getAnalyzerInfoFile(settings.buildDir, tokenizer.list.getSourceFilePath(), cfg, fileIndex);
+        std::string filename = AnalyzerInformation::getAnalyzerInfoFile(settings.buildDir, Path::simplifyPath(tokenizer.list.getSourceFilePath()), cfg, fsFileId);
         const std::string::size_type pos = filename.rfind(".a");
         if (pos != std::string::npos) {
             filename[pos+1] = 's';
diff --git a/lib/summaries.h b/lib/summaries.h
index ac3d40d840f..a7a314da9a8 100644
--- a/lib/summaries.h
+++ b/lib/summaries.h
@@ -29,7 +29,7 @@
 class Tokenizer;
 
 namespace Summaries {
-    CPPCHECKLIB std::string create(const Tokenizer &tokenizer, const std::string &cfg, int fileIndex);
+    CPPCHECKLIB std::string create(const Tokenizer &tokenizer, const std::string &cfg, std::size_t fsFileId);
     CPPCHECKLIB void loadReturn(const std::string &buildDir, std::set<std::string> &summaryReturn);
 }
 
diff --git a/oss-fuzz/Makefile b/oss-fuzz/Makefile
index ad7fb641024..195dcf50b70 100644
--- a/oss-fuzz/Makefile
+++ b/oss-fuzz/Makefile
@@ -329,7 +329,7 @@ $(libcppdir)/settings.o: ../lib/settings.cpp ../externals/picojson/picojson.h ..
 $(libcppdir)/standards.o: ../lib/standards.cpp ../externals/simplecpp/simplecpp.h ../lib/config.h ../lib/standards.h ../lib/utils.h
 	$(CXX) ${LIB_FUZZING_ENGINE} $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(libcppdir)/standards.cpp
 
-$(libcppdir)/summaries.o: ../lib/summaries.cpp ../lib/addoninfo.h ../lib/analyzerinfo.h ../lib/checkers.h ../lib/config.h ../lib/errortypes.h ../lib/library.h ../lib/mathlib.h ../lib/platform.h ../lib/settings.h ../lib/smallvector.h ../lib/sourcelocation.h ../lib/standards.h ../lib/summaries.h ../lib/symboldatabase.h ../lib/templatesimplifier.h ../lib/token.h ../lib/tokenize.h ../lib/tokenlist.h ../lib/utils.h ../lib/vfvalue.h
+$(libcppdir)/summaries.o: ../lib/summaries.cpp ../lib/addoninfo.h ../lib/analyzerinfo.h ../lib/checkers.h ../lib/config.h ../lib/errortypes.h ../lib/library.h ../lib/mathlib.h ../lib/path.h ../lib/platform.h ../lib/settings.h ../lib/smallvector.h ../lib/sourcelocation.h ../lib/standards.h ../lib/summaries.h ../lib/symboldatabase.h ../lib/templatesimplifier.h ../lib/token.h ../lib/tokenize.h ../lib/tokenlist.h ../lib/utils.h ../lib/vfvalue.h
 	$(CXX) ${LIB_FUZZING_ENGINE} $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(libcppdir)/summaries.cpp
 
 $(libcppdir)/suppressions.o: ../lib/suppressions.cpp ../externals/tinyxml2/tinyxml2.h ../lib/config.h ../lib/errorlogger.h ../lib/errortypes.h ../lib/filesettings.h ../lib/mathlib.h ../lib/path.h ../lib/pathmatch.h ../lib/platform.h ../lib/smallvector.h ../lib/standards.h ../lib/suppressions.h ../lib/templatesimplifier.h ../lib/token.h ../lib/tokenize.h ../lib/tokenlist.h ../lib/utils.h ../lib/vfvalue.h ../lib/xml.h
diff --git a/test/testanalyzerinformation.cpp b/test/testanalyzerinformation.cpp
index 35e86e0dbb8..6f85cd2a882 100644
--- a/test/testanalyzerinformation.cpp
+++ b/test/testanalyzerinformation.cpp
@@ -59,9 +59,9 @@ class TestAnalyzerInformation : public TestFixture {
     void filesTextDuplicateFile() const {
         std::list<FileSettings> fileSettings;
         fileSettings.emplace_back("a.c", Standards::Language::C, 10);
-        fileSettings.back().fileIndex = 0;
+        fileSettings.back().file.setFsFileId(0);
         fileSettings.emplace_back("a.c", Standards::Language::C, 10);
-        fileSettings.back().fileIndex = 1;
+        fileSettings.back().file.setFsFileId(1);
 
         const char expected[] = "a.a1:::a.c\n"
                                 "a.a2::1:a.c\n";
@@ -90,19 +90,19 @@ class TestAnalyzerInformation : public TestFixture {
         ASSERT_EQUALS(true, info.parse("a:b::d"));
         ASSERT_EQUALS("a", info.afile);
         ASSERT_EQUALS("b", info.cfg);
-        ASSERT_EQUALS(0, info.fileIndex);
+        ASSERT_EQUALS(0, info.fsFileId);
         ASSERT_EQUALS("d", info.sourceFile);
 
         ASSERT_EQUALS(true, info.parse("e:f:12:g"));
         ASSERT_EQUALS("e", info.afile);
         ASSERT_EQUALS("f", info.cfg);
-        ASSERT_EQUALS(12, info.fileIndex);
+        ASSERT_EQUALS(12, info.fsFileId);
         ASSERT_EQUALS("g", info.sourceFile);
 
         ASSERT_EQUALS(true, info.parse("odr1.a1:::C:/dm/cppcheck-fix-13333/test/cli/whole-program/odr1.cpp"));
         ASSERT_EQUALS("odr1.a1", info.afile);
         ASSERT_EQUALS("", info.cfg);
-        ASSERT_EQUALS(0, info.fileIndex);
+        ASSERT_EQUALS(0, info.fsFileId);
         ASSERT_EQUALS("C:/dm/cppcheck-fix-13333/test/cli/whole-program/odr1.cpp", info.sourceFile);
     }
 
diff --git a/test/testimportproject.cpp b/test/testimportproject.cpp
index 5e6db0163c8..9534ee58277 100644
--- a/test/testimportproject.cpp
+++ b/test/testimportproject.cpp
@@ -363,8 +363,8 @@ class TestImportProject : public TestFixture {
         ASSERT_EQUALS(2, importer.fileSettings.size());
         const FileSettings &fs1 = importer.fileSettings.front();
         const FileSettings &fs2 = importer.fileSettings.back();
-        ASSERT_EQUALS(0, fs1.fileIndex);
-        ASSERT_EQUALS(1, fs2.fileIndex);
+        ASSERT_EQUALS(0, fs1.file.fsFileId());
+        ASSERT_EQUALS(1, fs2.file.fsFileId());
     }
 
     void importCompileCommands14() const { // #14156