diff --git a/Source/CPack/cmCPackDebGenerator.cxx b/Source/CPack/cmCPackDebGenerator.cxx
index 7fd76df65..1ad415251 100644
--- a/Source/CPack/cmCPackDebGenerator.cxx
+++ b/Source/CPack/cmCPackDebGenerator.cxx
@@ -50,8 +50,8 @@ int cmCPackDebGenerator::InitializeInternal()
   return this->Superclass::InitializeInternal();
 }
 
-int cmCPackDebGenerator::PackageOnePack(std::string initialTopLevel,
-                                        std::string packageName)
+int cmCPackDebGenerator::PackageOnePack(std::string const& initialTopLevel,
+                                        std::string const& packageName)
 {
   int retval = 1;
   // Begin the archive for this pack
diff --git a/Source/CPack/cmCPackDebGenerator.h b/Source/CPack/cmCPackDebGenerator.h
index f640ab4a6..ff34ca571 100644
--- a/Source/CPack/cmCPackDebGenerator.h
+++ b/Source/CPack/cmCPackDebGenerator.h
@@ -49,7 +49,8 @@ protected:
   /**
    * This method factors out the work done in component packaging case.
    */
-  int PackageOnePack(std::string initialToplevel, std::string packageName);
+  int PackageOnePack(std::string const& initialToplevel,
+                     std::string const& packageName);
   /**
    * The method used to package files when component
    * install is used. This will create one
diff --git a/Source/CPack/cmCPackRPMGenerator.cxx b/Source/CPack/cmCPackRPMGenerator.cxx
index a4b9a47ec..9827b7099 100644
--- a/Source/CPack/cmCPackRPMGenerator.cxx
+++ b/Source/CPack/cmCPackRPMGenerator.cxx
@@ -61,8 +61,8 @@ void cmCPackRPMGenerator::AddGeneratedPackageNames()
   packageFileNames.push_back(fileNames.substr(pos1, pos2 - pos1));
 }
 
-int cmCPackRPMGenerator::PackageOnePack(std::string initialToplevel,
-                                        std::string packageName)
+int cmCPackRPMGenerator::PackageOnePack(std::string const& initialToplevel,
+                                        std::string const& packageName)
 {
   int retval = 1;
   // Begin the archive for this pack
diff --git a/Source/CPack/cmCPackRPMGenerator.h b/Source/CPack/cmCPackRPMGenerator.h
index 40b9bb863..b39f2c2fc 100644
--- a/Source/CPack/cmCPackRPMGenerator.h
+++ b/Source/CPack/cmCPackRPMGenerator.h
@@ -54,7 +54,8 @@ protected:
   /**
    * This method factors out the work done in component packaging case.
    */
-  int PackageOnePack(std::string initialToplevel, std::string packageName);
+  int PackageOnePack(std::string const& initialToplevel,
+                     std::string const& packageName);
   /**
    * The method used to package files when component
    * install is used. This will create one
diff --git a/Source/CTest/cmCTestCoverageHandler.cxx b/Source/CTest/cmCTestCoverageHandler.cxx
index 7f0bf2cc5..daefb5914 100644
--- a/Source/CTest/cmCTestCoverageHandler.cxx
+++ b/Source/CTest/cmCTestCoverageHandler.cxx
@@ -1356,7 +1356,6 @@ int cmCTestCoverageHandler::HandleLCovCoverage(
     return 0;
   }
   std::string testingDir = this->CTest->GetBinaryDir();
-  std::string tempDir = testingDir;
   std::string currentDirectory = cmSystemTools::GetCurrentWorkingDirectory();
 
   std::set<std::string> missingFiles;
@@ -1759,7 +1758,7 @@ int cmCTestCoverageHandler::HandleTracePyCoverage(
 }
 
 std::string cmCTestCoverageHandler::FindFile(
-  cmCTestCoverageHandlerContainer* cont, std::string fileName)
+  cmCTestCoverageHandlerContainer* cont, std::string const& fileName)
 {
   std::string fileNameNoE =
     cmSystemTools::GetFilenameWithoutLastExtension(fileName);
diff --git a/Source/CTest/cmCTestCoverageHandler.h b/Source/CTest/cmCTestCoverageHandler.h
index 4a2a60288..177321844 100644
--- a/Source/CTest/cmCTestCoverageHandler.h
+++ b/Source/CTest/cmCTestCoverageHandler.h
@@ -119,7 +119,7 @@ private:
   // Find the source file based on the source and build tree. This is used for
   // Trace.py mode, since that one does not tell us where the source file is.
   std::string FindFile(cmCTestCoverageHandlerContainer* cont,
-                       std::string fileName);
+                       std::string const& fileName);
 
   std::set<std::string> FindUncoveredFiles(
     cmCTestCoverageHandlerContainer* cont);
diff --git a/Source/CTest/cmCTestMultiProcessHandler.cxx b/Source/CTest/cmCTestMultiProcessHandler.cxx
index d155023ca..6f19b325a 100644
--- a/Source/CTest/cmCTestMultiProcessHandler.cxx
+++ b/Source/CTest/cmCTestMultiProcessHandler.cxx
@@ -500,7 +500,7 @@ void cmCTestMultiProcessHandler::ReadCostData()
   }
 }
 
-int cmCTestMultiProcessHandler::SearchByName(std::string name)
+int cmCTestMultiProcessHandler::SearchByName(std::string const& name)
 {
   int index = -1;
 
diff --git a/Source/CTest/cmCTestMultiProcessHandler.h b/Source/CTest/cmCTestMultiProcessHandler.h
index cb709cc0c..9ec1528af 100644
--- a/Source/CTest/cmCTestMultiProcessHandler.h
+++ b/Source/CTest/cmCTestMultiProcessHandler.h
@@ -84,7 +84,7 @@ protected:
   void UpdateCostData();
   void ReadCostData();
   // Return index of a test based on its name
-  int SearchByName(std::string name);
+  int SearchByName(std::string const& name);
 
   void CreateTestCostList();
 
diff --git a/Source/CTest/cmCTestSubmitCommand.cxx b/Source/CTest/cmCTestSubmitCommand.cxx
index fa9bd2cf7..664552af9 100644
--- a/Source/CTest/cmCTestSubmitCommand.cxx
+++ b/Source/CTest/cmCTestSubmitCommand.cxx
@@ -219,12 +219,11 @@ bool cmCTestSubmitCommand::CheckArgumentValue(std::string const& arg)
   }
 
   if (this->ArgumentDoing == ArgumentDoingFiles) {
-    std::string filename(arg);
-    if (cmSystemTools::FileExists(filename.c_str())) {
-      this->Files.insert(filename);
+    if (cmSystemTools::FileExists(arg.c_str())) {
+      this->Files.insert(arg);
     } else {
       std::ostringstream e;
-      e << "File \"" << filename << "\" does not exist. Cannot submit "
+      e << "File \"" << arg << "\" does not exist. Cannot submit "
         << "a non-existent file.";
       this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
       this->ArgumentDoing = ArgumentDoingError;
diff --git a/Source/CTest/cmCTestUploadCommand.cxx b/Source/CTest/cmCTestUploadCommand.cxx
index 6813cbcc4..c85db0208 100644
--- a/Source/CTest/cmCTestUploadCommand.cxx
+++ b/Source/CTest/cmCTestUploadCommand.cxx
@@ -46,13 +46,12 @@ bool cmCTestUploadCommand::CheckArgumentKeyword(std::string const& arg)
 bool cmCTestUploadCommand::CheckArgumentValue(std::string const& arg)
 {
   if (this->ArgumentDoing == ArgumentDoingFiles) {
-    std::string filename(arg);
-    if (cmSystemTools::FileExists(filename.c_str())) {
-      this->Files.insert(filename);
+    if (cmSystemTools::FileExists(arg.c_str())) {
+      this->Files.insert(arg);
       return true;
     } else {
       std::ostringstream e;
-      e << "File \"" << filename << "\" does not exist. Cannot submit "
+      e << "File \"" << arg << "\" does not exist. Cannot submit "
         << "a non-existent file.";
       this->Makefile->IssueMessage(cmake::FATAL_ERROR, e.str());
       this->ArgumentDoing = ArgumentDoingError;
diff --git a/Source/CTest/cmParseBlanketJSCoverage.cxx b/Source/CTest/cmParseBlanketJSCoverage.cxx
index 152c354ac..fa539e45b 100644
--- a/Source/CTest/cmParseBlanketJSCoverage.cxx
+++ b/Source/CTest/cmParseBlanketJSCoverage.cxx
@@ -46,7 +46,7 @@ public:
       return line.substr(begIndex, line.npos);
     }
   }
-  bool ParseFile(std::string file)
+  bool ParseFile(std::string const& file)
   {
     FileLinesType localCoverageVector;
     std::string filename;
@@ -138,7 +138,7 @@ bool cmParseBlanketJSCoverage::LoadCoverageData(std::vector<std::string> files)
   return true;
 }
 
-bool cmParseBlanketJSCoverage::ReadJSONFile(std::string file)
+bool cmParseBlanketJSCoverage::ReadJSONFile(std::string const& file)
 {
   cmParseBlanketJSCoverage::JSONParser parser(this->Coverage);
   cmCTestOptionalLog(this->CTest, HANDLER_VERBOSE_OUTPUT,
diff --git a/Source/CTest/cmParseBlanketJSCoverage.h b/Source/CTest/cmParseBlanketJSCoverage.h
index 4fc64e7db..a4f66705b 100644
--- a/Source/CTest/cmParseBlanketJSCoverage.h
+++ b/Source/CTest/cmParseBlanketJSCoverage.h
@@ -35,7 +35,7 @@ public:
                            cmCTest* ctest);
   bool LoadCoverageData(std::vector<std::string> files);
   //  Read the JSON output
-  bool ReadJSONFile(std::string file);
+  bool ReadJSONFile(std::string const& file);
 
 protected:
   class JSONParser;
diff --git a/Source/CTest/cmParseDelphiCoverage.cxx b/Source/CTest/cmParseDelphiCoverage.cxx
index 2e06078ba..9d86ce957 100644
--- a/Source/CTest/cmParseDelphiCoverage.cxx
+++ b/Source/CTest/cmParseDelphiCoverage.cxx
@@ -22,7 +22,7 @@ public:
   virtual ~HTMLParser() {}
 
   bool initializeDelphiFile(
-    const std::string filename,
+    std::string const& filename,
     cmParseDelphiCoverage::HTMLParser::FileLinesType& coverageVector)
   {
     std::string line;
@@ -197,7 +197,7 @@ cmParseDelphiCoverage::cmParseDelphiCoverage(
 }
 
 bool cmParseDelphiCoverage::LoadCoverageData(
-  const std::vector<std::string> files)
+  std::vector<std::string> const& files)
 {
   size_t i;
   std::string path;
diff --git a/Source/CTest/cmParseDelphiCoverage.h b/Source/CTest/cmParseDelphiCoverage.h
index 06dea2b16..c1c495cee 100644
--- a/Source/CTest/cmParseDelphiCoverage.h
+++ b/Source/CTest/cmParseDelphiCoverage.h
@@ -28,7 +28,7 @@ class cmParseDelphiCoverage
 {
 public:
   cmParseDelphiCoverage(cmCTestCoverageHandlerContainer& cont, cmCTest* ctest);
-  bool LoadCoverageData(const std::vector<std::string> files);
+  bool LoadCoverageData(std::vector<std::string> const& files);
   bool ReadDelphiHTML(const char* file);
   // Read a single HTML file from output
   bool ReadHTMLFile(const char* f);
diff --git a/Source/CTest/cmParseJacocoCoverage.cxx b/Source/CTest/cmParseJacocoCoverage.cxx
index 6afaca6b3..335535d92 100644
--- a/Source/CTest/cmParseJacocoCoverage.cxx
+++ b/Source/CTest/cmParseJacocoCoverage.cxx
@@ -85,7 +85,7 @@ protected:
     }
   }
 
-  virtual bool FindPackagePath(const std::string fileName)
+  virtual bool FindPackagePath(std::string const& fileName)
   {
     // Search for the source file in the source directory.
     if (this->PackagePathFound(fileName, this->Coverage.SourceDir)) {
@@ -99,8 +99,8 @@ protected:
     return false;
   }
 
-  virtual bool PackagePathFound(const std::string fileName,
-                                const std::string baseDir)
+  virtual bool PackagePathFound(std::string const& fileName,
+                                std::string const& baseDir)
   {
     // Search for the file in the baseDir and its subdirectories.
     std::string packageGlob = baseDir;
@@ -149,7 +149,7 @@ cmParseJacocoCoverage::cmParseJacocoCoverage(
 }
 
 bool cmParseJacocoCoverage::LoadCoverageData(
-  const std::vector<std::string> files)
+  std::vector<std::string> const& files)
 {
   // load all the jacoco.xml files in the source directory
   cmsys::Directory dir;
diff --git a/Source/CTest/cmParseJacocoCoverage.h b/Source/CTest/cmParseJacocoCoverage.h
index fa31d4779..bcd472e2b 100644
--- a/Source/CTest/cmParseJacocoCoverage.h
+++ b/Source/CTest/cmParseJacocoCoverage.h
@@ -27,7 +27,7 @@ class cmParseJacocoCoverage
 {
 public:
   cmParseJacocoCoverage(cmCTestCoverageHandlerContainer& cont, cmCTest* ctest);
-  bool LoadCoverageData(const std::vector<std::string> files);
+  bool LoadCoverageData(std::vector<std::string> const& files);
 
   std::string PackageName;
   std::string FileName;
diff --git a/Source/cmCTest.cxx b/Source/cmCTest.cxx
index 64e80783f..bc36c5adc 100644
--- a/Source/cmCTest.cxx
+++ b/Source/cmCTest.cxx
@@ -67,7 +67,7 @@
   std::cerr << __LINE__ << " ";                                               \
   std::cerr
 
-struct tm* cmCTest::GetNightlyTime(std::string str, bool tomorrowtag)
+struct tm* cmCTest::GetNightlyTime(std::string const& str, bool tomorrowtag)
 {
   struct tm* lctime;
   time_t tctime = time(0);
@@ -170,8 +170,8 @@ static size_t HTTPResponseCallback(void* ptr, size_t size, size_t nmemb,
 }
 
 int cmCTest::HTTPRequest(std::string url, HTTPMethod method,
-                         std::string& response, std::string fields,
-                         std::string putFile, int timeout)
+                         std::string& response, std::string const& fields,
+                         std::string const& putFile, int timeout)
 {
   CURL* curl;
   FILE* file;
@@ -1481,7 +1481,7 @@ int cmCTest::GenerateNotesFile(const char* cfiles)
   return this->GenerateNotesFile(files);
 }
 
-std::string cmCTest::Base64GzipEncodeFile(std::string file)
+std::string cmCTest::Base64GzipEncodeFile(std::string const& file)
 {
   std::string tarFile = file + "_temp.tar.gz";
   std::vector<std::string> files;
@@ -1499,7 +1499,7 @@ std::string cmCTest::Base64GzipEncodeFile(std::string file)
   return base64;
 }
 
-std::string cmCTest::Base64EncodeFile(std::string file)
+std::string cmCTest::Base64EncodeFile(std::string const& file)
 {
   size_t const len = cmSystemTools::FileLength(file);
   cmsys::ifstream ifs(file.c_str(), std::ios::in
@@ -2208,7 +2208,7 @@ void cmCTest::SetNotesFiles(const char* notes)
   this->NotesFiles = notes;
 }
 
-void cmCTest::SetStopTime(std::string time)
+void cmCTest::SetStopTime(std::string const& time)
 {
   this->StopTime = time;
   this->DetermineNextDayStop();
diff --git a/Source/cmCTest.h b/Source/cmCTest.h
index 1c3490e2b..65ecaa4dd 100644
--- a/Source/cmCTest.h
+++ b/Source/cmCTest.h
@@ -108,8 +108,8 @@ public:
    * Perform an HTTP request.
    */
   static int HTTPRequest(std::string url, HTTPMethod method,
-                         std::string& response, std::string fields = "",
-                         std::string putFile = "", int timeout = 0);
+                         std::string& response, std::string const& fields = "",
+                         std::string const& putFile = "", int timeout = 0);
 #endif
 
   /** Get a testing part id from its string name.  Returns PartCount
@@ -143,7 +143,7 @@ public:
   /*
    * A utility function that returns the nightly time
    */
-  struct tm* GetNightlyTime(std::string str, bool tomorrowtag);
+  struct tm* GetNightlyTime(std::string const& str, bool tomorrowtag);
 
   /*
    * Is the tomorrow tag set?
@@ -211,9 +211,9 @@ public:
   std::string CurrentTime();
 
   //! tar/gzip and then base 64 encode a file
-  std::string Base64GzipEncodeFile(std::string file);
+  std::string Base64GzipEncodeFile(std::string const& file);
   //! base64 encode a file
-  std::string Base64EncodeFile(std::string file);
+  std::string Base64EncodeFile(std::string const& file);
 
   /**
    * Return the time remaining that the script is allowed to run in
@@ -240,7 +240,7 @@ public:
   std::string GetCDashVersion();
 
   std::string GetStopTime() { return this->StopTime; }
-  void SetStopTime(std::string time);
+  void SetStopTime(std::string const& time);
 
   // Used for parallel ctest job scheduling
   std::string GetScheduleType() { return this->ScheduleType; }
diff --git a/Source/cmExternalMakefileProjectGenerator.cxx b/Source/cmExternalMakefileProjectGenerator.cxx
index e3c8fa44c..0e42d759e 100644
--- a/Source/cmExternalMakefileProjectGenerator.cxx
+++ b/Source/cmExternalMakefileProjectGenerator.cxx
@@ -43,9 +43,8 @@ std::string cmExternalMakefileProjectGenerator::GetGlobalGeneratorName(
     return "";
   }
 
-  std::string currentName = fullName;
   // if we get only the short name, take the first global generator as default
-  if (currentName == this->GetName()) {
+  if (fullName == this->GetName()) {
     return this->SupportedGlobalGenerators[0];
   }
 
@@ -53,7 +52,7 @@ std::string cmExternalMakefileProjectGenerator::GetGlobalGeneratorName(
   for (std::vector<std::string>::const_iterator it =
          this->SupportedGlobalGenerators.begin();
        it != this->SupportedGlobalGenerators.end(); ++it) {
-    if (this->CreateFullGeneratorName(*it, this->GetName()) == currentName) {
+    if (this->CreateFullGeneratorName(*it, this->GetName()) == fullName) {
       return *it;
     }
   }
diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index 249a3b637..a1764a38a 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -2746,7 +2746,7 @@ std::string cmGlobalGenerator::EscapeJSON(const std::string& s)
 }
 
 void cmGlobalGenerator::SetFilenameTargetDepends(
-  cmSourceFile* sf, std::set<cmGeneratorTarget const*> tgts)
+  cmSourceFile* sf, std::set<cmGeneratorTarget const*> const& tgts)
 {
   this->FilenameTargetDepends[sf] = tgts;
 }
diff --git a/Source/cmGlobalGenerator.h b/Source/cmGlobalGenerator.h
index fcf8127cd..2575911ff 100644
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -348,8 +348,8 @@ public:
 
   void CreateEvaluationSourceFiles(std::string const& config) const;
 
-  void SetFilenameTargetDepends(cmSourceFile* sf,
-                                std::set<const cmGeneratorTarget*> tgts);
+  void SetFilenameTargetDepends(
+    cmSourceFile* sf, std::set<cmGeneratorTarget const*> const& tgts);
   const std::set<const cmGeneratorTarget*>& GetFilenameTargetDepends(
     cmSourceFile* sf) const;
 
diff --git a/Source/cmGlobalNinjaGenerator.cxx b/Source/cmGlobalNinjaGenerator.cxx
index a1c9d76e4..143ad9213 100644
--- a/Source/cmGlobalNinjaGenerator.cxx
+++ b/Source/cmGlobalNinjaGenerator.cxx
@@ -46,15 +46,14 @@ void cmGlobalNinjaGenerator::WriteComment(std::ostream& os,
   if (comment.empty())
     return;
 
-  std::string replace = comment;
   std::string::size_type lpos = 0;
   std::string::size_type rpos;
   os << "\n#############################################\n";
-  while ((rpos = replace.find('\n', lpos)) != std::string::npos) {
-    os << "# " << replace.substr(lpos, rpos - lpos) << "\n";
+  while ((rpos = comment.find('\n', lpos)) != std::string::npos) {
+    os << "# " << comment.substr(lpos, rpos - lpos) << "\n";
     lpos = rpos + 1;
   }
-  os << "# " << replace.substr(lpos) << "\n\n";
+  os << "# " << comment.substr(lpos) << "\n\n";
 }
 
 std::string cmGlobalNinjaGenerator::EncodeRuleName(std::string const& name)
diff --git a/Source/cmInstallFilesGenerator.cxx b/Source/cmInstallFilesGenerator.cxx
index a2cfc5a2f..8c1b357d3 100644
--- a/Source/cmInstallFilesGenerator.cxx
+++ b/Source/cmInstallFilesGenerator.cxx
@@ -61,7 +61,7 @@ std::string cmInstallFilesGenerator::GetDestination(
 }
 
 void cmInstallFilesGenerator::AddFilesInstallRule(
-  std::ostream& os, const std::string config, Indent const& indent,
+  std::ostream& os, std::string const& config, Indent const& indent,
   std::vector<std::string> const& files)
 {
   // Write code to install the files.
diff --git a/Source/cmInstallFilesGenerator.h b/Source/cmInstallFilesGenerator.h
index 86b589928..0e738d396 100644
--- a/Source/cmInstallFilesGenerator.h
+++ b/Source/cmInstallFilesGenerator.h
@@ -38,7 +38,7 @@ protected:
   virtual void GenerateScriptForConfig(std::ostream& os,
                                        const std::string& config,
                                        Indent const& indent);
-  void AddFilesInstallRule(std::ostream& os, const std::string config,
+  void AddFilesInstallRule(std::ostream& os, std::string const& config,
                            Indent const& indent,
                            std::vector<std::string> const& files);
 
diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 2de12ba03..e91eb4688 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -1766,13 +1766,12 @@ static void AddVisibilityCompileOption(std::string& flags,
                                        const std::string& lang,
                                        std::string* warnCMP0063)
 {
-  std::string l(lang);
-  std::string compileOption = "CMAKE_" + l + "_COMPILE_OPTIONS_VISIBILITY";
+  std::string compileOption = "CMAKE_" + lang + "_COMPILE_OPTIONS_VISIBILITY";
   const char* opt = lg->GetMakefile()->GetDefinition(compileOption);
   if (!opt) {
     return;
   }
-  std::string flagDefine = l + "_VISIBILITY_PRESET";
+  std::string flagDefine = lang + "_VISIBILITY_PRESET";
 
   const char* prop = target->GetProperty(flagDefine);
   if (!prop) {
diff --git a/Source/cmLocalUnixMakefileGenerator3.cxx b/Source/cmLocalUnixMakefileGenerator3.cxx
index 653ea40c7..f60a595e4 100644
--- a/Source/cmLocalUnixMakefileGenerator3.cxx
+++ b/Source/cmLocalUnixMakefileGenerator3.cxx
@@ -1178,10 +1178,9 @@ void cmLocalUnixMakefileGenerator3::AppendEcho(
 }
 
 std::string cmLocalUnixMakefileGenerator3::CreateMakeVariable(
-  const std::string& sin, const std::string& s2in)
+  const std::string& sin, const std::string& s2)
 {
   std::string s = sin;
-  std::string s2 = s2in;
   std::string unmodified = s;
   unmodified += s2;
   // if there is no restriction on the length of make variables
diff --git a/Source/cmMakefileTargetGenerator.cxx b/Source/cmMakefileTargetGenerator.cxx
index 0939698da..93f9e498b 100644
--- a/Source/cmMakefileTargetGenerator.cxx
+++ b/Source/cmMakefileTargetGenerator.cxx
@@ -294,7 +294,7 @@ void cmMakefileTargetGenerator::MacOSXContentGeneratorType::operator()(
     this->Generator->OSXBundleGenerator->InitMacOSXContentDirectory(pkgloc);
 
   // Get the input file location.
-  std::string input = source.GetFullPath();
+  std::string const& input = source.GetFullPath();
 
   // Get the output file location.
   std::string output = macdir;
diff --git a/Source/cmSourceGroup.cxx b/Source/cmSourceGroup.cxx
index c09d596c8..394b33a47 100644
--- a/Source/cmSourceGroup.cxx
+++ b/Source/cmSourceGroup.cxx
@@ -103,7 +103,7 @@ const std::vector<const cmSourceFile*>& cmSourceGroup::GetSourceFiles() const
   return this->SourceFiles;
 }
 
-void cmSourceGroup::AddChild(cmSourceGroup child)
+void cmSourceGroup::AddChild(cmSourceGroup const& child)
 {
   this->Internal->GroupChildren.push_back(child);
 }
diff --git a/Source/cmSourceGroup.h b/Source/cmSourceGroup.h
index 5a551f8cf..8603e95e7 100644
--- a/Source/cmSourceGroup.h
+++ b/Source/cmSourceGroup.h
@@ -52,7 +52,7 @@ public:
   /**
    * Add child to this sourcegroup
    */
-  void AddChild(cmSourceGroup child);
+  void AddChild(cmSourceGroup const& child);
 
   /**
    * Looks up child and returns it
diff --git a/Source/cmState.cxx b/Source/cmState.cxx
index 09b11b28b..04f07cecf 100644
--- a/Source/cmState.cxx
+++ b/Source/cmState.cxx
@@ -1616,7 +1616,7 @@ bool cmState::Snapshot::StrictWeakOrder::operator()(
 
 void cmState::Directory::SetProperty(const std::string& prop,
                                      const char* value,
-                                     cmListFileBacktrace lfbt)
+                                     cmListFileBacktrace const& lfbt)
 {
   if (prop == "INCLUDE_DIRECTORIES") {
     if (!value) {
@@ -1648,7 +1648,7 @@ void cmState::Directory::SetProperty(const std::string& prop,
 
 void cmState::Directory::AppendProperty(const std::string& prop,
                                         const char* value, bool asString,
-                                        cmListFileBacktrace lfbt)
+                                        cmListFileBacktrace const& lfbt)
 {
   if (prop == "INCLUDE_DIRECTORIES") {
     this->AppendIncludeDirectoriesEntry(value, lfbt);
diff --git a/Source/cmState.h b/Source/cmState.h
index 7ecac5631..18c45b83f 100644
--- a/Source/cmState.h
+++ b/Source/cmState.h
@@ -164,9 +164,9 @@ public:
     void ClearCompileOptions();
 
     void SetProperty(const std::string& prop, const char* value,
-                     cmListFileBacktrace lfbt);
+                     cmListFileBacktrace const& lfbt);
     void AppendProperty(const std::string& prop, const char* value,
-                        bool asString, cmListFileBacktrace lfbt);
+                        bool asString, cmListFileBacktrace const& lfbt);
     const char* GetProperty(const std::string& prop) const;
     const char* GetProperty(const std::string& prop, bool chain) const;
     bool GetPropertyAsBool(const std::string& prop) const;
diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index e4d6656d4..89ea9559d 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -2296,10 +2296,8 @@ void displayMessage(cmake::MessageType t, std::ostringstream& msg)
 }
 
 void cmake::IssueMessage(cmake::MessageType t, std::string const& text,
-                         cmListFileBacktrace const& bt, bool force)
+                         cmListFileBacktrace const& backtrace, bool force)
 {
-  cmListFileBacktrace backtrace = bt;
-
   if (!force) {
     // override the message type, if needed, for warnings and errors
     cmake::MessageType override = this->ConvertMessageType(t);
diff --git a/Tests/CMakeLib/testRST.cxx b/Tests/CMakeLib/testRST.cxx
index a575d0d8c..e5a96c22c 100644
--- a/Tests/CMakeLib/testRST.cxx
+++ b/Tests/CMakeLib/testRST.cxx
@@ -13,7 +13,7 @@
 
 #include "cmSystemTools.h"
 
-void reportLine(std::ostream& os, bool ret, std::string line, bool eol)
+void reportLine(std::ostream& os, bool ret, std::string const& line, bool eol)
 {
   if (ret) {
     os << "\"" << line << "\" (" << (eol ? "with EOL" : "without EOL") << ")";