diff --git a/components/codetools/definetemplates.pas b/components/codetools/definetemplates.pas
index 47375ecf54..56ae640abc 100644
--- a/components/codetools/definetemplates.pas
+++ b/components/codetools/definetemplates.pas
@@ -401,8 +401,8 @@ type
     class procedure MergeXMLConfig(ParentDefTempl: TDefineTemplate;
                   var FirstSibling, LastSibling:TDefineTemplate;
                   XMLConfig: TXMLConfig; const Path, NewNamePrefix: string);
-    constructor Create(const AName, ADescription, AVariable, AValue: string;
-                       AnAction: TDefineAction);
+    constructor Create(const AName, ADescription, AVariable: string;
+                       AValue: string; AnAction: TDefineAction);
     constructor Create;
     destructor Destroy; override;
     procedure ConsistencyCheck;
@@ -4629,8 +4629,9 @@ begin
   inherited Create;
 end;
 
-constructor TDefineTemplate.Create(const AName, ADescription, AVariable,
+constructor TDefineTemplate.Create(const AName, ADescription, AVariable: string;
   AValue: string; AnAction: TDefineAction);
+// Don't use "const" for AValue parameter.
 begin
   inherited Create;
   Name:=AName;
diff --git a/ide/compileroptions.pp b/ide/compileroptions.pp
index 92af9e5352..3b8f4b2112 100644
--- a/ide/compileroptions.pp
+++ b/ide/compileroptions.pp
@@ -261,7 +261,7 @@ const
   CompilerOptionMacroPlatformIndependent = 1;
 
 type
-  TLocalSubstitutionEvent = function(const s: string;
+  TLocalSubstitutionEvent = function(s: string;
                                 PlatformIndependent: boolean): string of object;
 
   TInheritedCompOptsParseTypesStrings =
@@ -303,7 +303,7 @@ type
     function GetParsedPIValue(Option: TParsedCompilerOptString): string;// platform independent
     procedure SetUnparsedValue(Option: TParsedCompilerOptString;
                                const NewValue: string);
-    function DoParseOption(const OptionText: string;
+    function DoParseOption(OptionText: string;
                            Option: TParsedCompilerOptString;
                            PlatformIndependent: boolean): string;
     procedure Assign(Src: TParsedCompilerOptions);
@@ -3858,8 +3858,9 @@ begin
   Values[Option].UnparsedValue:=NewValue;
 end;
 
-function TParsedCompilerOptions.DoParseOption(const OptionText: string;
+function TParsedCompilerOptions.DoParseOption(OptionText: string;
   Option: TParsedCompilerOptString; PlatformIndependent: boolean): string;
+// Don't use "const" for OptionText parameter.
 
   function GetBaseDir: string;
   begin
@@ -3878,67 +3879,67 @@ function TParsedCompilerOptions.DoParseOption(const OptionText: string;
     aFilename:=TrimFilename(aFilename);
     if (aFilename<>'') and (not FilenameIsAbsolute(aFilename)) then begin
       BaseDirectory:=GetBaseDir;
-      if (BaseDirectory<>'') then aFilename:=TrimFilename(BaseDirectory+aFilename);
+      if (BaseDirectory<>'') then
+        aFilename:=TrimFilename(BaseDirectory+aFilename);
     end;
   end;
 
 var
-  s: String;
   BaseDirectory, h: String;
 begin
-  s:=OptionText;
+  Result:=OptionText;
 
   // apply overrides
   if not PlatformIndependent then begin
     if Option=pcosOutputDir then begin
       if Assigned(OnGetOutputDirectoryOverride) then
-        OnGetOutputDirectoryOverride(Self,s,bmgtAll);
+        OnGetOutputDirectoryOverride(Self,Result,bmgtAll);
     end;
   end;
 
   // parse locally (macros depending on owner, like pkgdir and build macros)
   if Assigned(OnLocalSubstitute) then
   begin
-    //DebugLn(['TParsedCompilerOptions.DoParseOption local "',s,'" ...']);
-    s:=OnLocalSubstitute(s,PlatformIndependent)
+    //DebugLn(['TParsedCompilerOptions.DoParseOption local "',Result,'" ...']);
+    Result:=OnLocalSubstitute(Result,PlatformIndependent)
   end else
   begin
-    //DebugLn(['TParsedCompilerOptions.DoParseOption global "',s,'" ...']);
-    s:=ParseString(Self,s,PlatformIndependent);
+    //DebugLn(['TParsedCompilerOptions.DoParseOption global "',Result,'" ...']);
+    Result:=ParseString(Self,Result,PlatformIndependent);
   end;
-  //DebugLn(['TParsedCompilerOptions.DoParseOption complete "',s,'" ...']);
+  //DebugLn(['TParsedCompilerOptions.DoParseOption complete "',Result,'" ...']);
   // improve
   if Option=pcosBaseDir then
     // base directory
-    s:=AppendPathDelim(TrimFilename(s))
+    Result:=AppendPathDelim(TrimFilename(Result))
   else if Option in ParsedCompilerFilenames then
   begin
     // make filename absolute
-    //debugln(['TParsedCompilerOptions.DoParseOption ',ParsedCompilerOptsVars[Option],' s="',s,'"']);
-    if (Option in ParsedCompilerExecutables) and (ExtractFilePath(s)='') then
+    //debugln(['TParsedCompilerOptions.DoParseOption ',ParsedCompilerOptsVars[Option],' Result="',Result,'"']);
+    if (Option in ParsedCompilerExecutables) and (ExtractFilePath(Result)='') then
     begin
-      h:=FileUtil.FindDefaultExecutablePath(s,GetBaseDir);
-      if h<>'' then s:=h;
+      h:=FileUtil.FindDefaultExecutablePath(Result,GetBaseDir);
+      if h<>'' then
+        Result:=h;
     end;
-    MakeFilenameAbsolute(s);
+    MakeFilenameAbsolute(Result);
   end
   else if Option in ParsedCompilerDirectories then
   begin
     // make directory absolute
-    s:=TrimFilename(s);
+    Result:=TrimFilename(Result);
     if Option<>pcosBaseDir then
-      MakeFilenameAbsolute(s);
-    s:=AppendPathDelim(s);
+      MakeFilenameAbsolute(Result);
+    Result:=AppendPathDelim(Result);
   end
   else if Option in ParsedCompilerSearchPaths then
   begin
     // make search paths absolute
     BaseDirectory:=GetBaseDir;
-    s:=TrimSearchPath(s,BaseDirectory);
+    Result:=TrimSearchPath(Result,BaseDirectory);
   end else if Option=pcosCustomOptions then begin
-    s:=SpecialCharsToSpaces(s,true);
+    Result:=SpecialCharsToSpaces(Result,true);
   end;
-  Result:=s;
 end;
 
 procedure TParsedCompilerOptions.Assign(Src: TParsedCompilerOptions);
diff --git a/ide/project.pp b/ide/project.pp
index 09a97cc27a..c2b7b75891 100644
--- a/ide/project.pp
+++ b/ide/project.pp
@@ -554,7 +554,7 @@ type
     procedure SetUnitPaths(const AValue: string); override;
     procedure SetUnitOutputDir(const AValue: string); override;
     procedure SetConditionals(AValue: string); override;
-    function SubstituteProjectMacros(const s: string;
+    function SubstituteProjectMacros(s: string;
                                      PlatformIndependent: boolean): string;
   public
     constructor Create(const AOwner: TObject); override;
@@ -6526,8 +6526,9 @@ begin
   inherited SetConditionals(AValue);
 end;
 
-function TProjectCompilerOptions.SubstituteProjectMacros(const s: string;
+function TProjectCompilerOptions.SubstituteProjectMacros(s: string;
   PlatformIndependent: boolean): string;
+// Don't use "const" for s parameter.
 begin
   Result:=s;
   if LazProject=nil then exit;
diff --git a/packager/fppkghelper.pas b/packager/fppkghelper.pas
index ea9b999190..d86253b237 100644
--- a/packager/fppkghelper.pas
+++ b/packager/fppkghelper.pas
@@ -34,7 +34,7 @@ type
     class function Instance: TFppkgHelper;
     function HasPackage(const PackageName: string): Boolean;
     procedure ListPackages(AList: TStringList);
-    function GetPackageUnitPath(const PackageName: string): string;
+    function GetPackageUnitPath(PackageName: string): string;
     function IsProperlyConfigured(out Message: string): Boolean;
     function GetCompilerFilename: string;
     function GetConfigurationFileName: string;
@@ -154,7 +154,8 @@ begin
     end;
 end;
 
-function TFppkgHelper.GetPackageUnitPath(const PackageName: string): string;
+function TFppkgHelper.GetPackageUnitPath(PackageName: string): string;
+// Don't use "const" for PackageName parameter.
 var
   FppkgPackage: TFPPackage;
 {$IF not (FPC_FULLVERSION>30300)}
diff --git a/packager/packagedefs.pas b/packager/packagedefs.pas
index e0026c0d9f..b278e2c0bc 100644
--- a/packager/packagedefs.pas
+++ b/packager/packagedefs.pas
@@ -652,7 +652,7 @@ type
     function GetSrcPath(RelativeToBaseDir: boolean): string;
     function GetFPDocPackageName: string;
     function NeedsDefineTemplates: boolean;
-    function SubstitutePkgMacros(const s: string; PlatformIndependent: boolean): string;
+    function SubstitutePkgMacros(s: string; PlatformIndependent: boolean): string;
     procedure WriteInheritedUnparsedOptions;
     function GetActiveBuildMethod: TBuildMethod;
     // files
@@ -2235,8 +2235,8 @@ begin
   FUserReadOnly:=AValue;
 end;
 
-function TLazPackage.SubstitutePkgMacros(const s: string;
-  PlatformIndependent: boolean): string;
+function TLazPackage.SubstitutePkgMacros(s: string; PlatformIndependent: boolean): string;
+// Don't use "const" for s parameter.
 begin
   Result:=s;
   if PlatformIndependent then
@@ -3840,11 +3840,10 @@ end;
 function TLazPackage.GetOutputDirectory(UseOverride: boolean = true): string;
 begin
   if HasDirectory then begin
-    if GetActiveBuildMethod = bmFPMake then begin
-      Result :=TFppkgHelper.Instance.GetPackageUnitPath(name);
-    end else begin
+    if GetActiveBuildMethod = bmFPMake then
+      Result :=TFppkgHelper.Instance.GetPackageUnitPath(name)
+    else
       Result:=CompilerOptions.ParsedOpts.GetParsedValue(pcosOutputDir,UseOverride);
-    end;
   end else
     Result:='';
 end;