diff --git a/components/codetools/codetoolmanager.pas b/components/codetools/codetoolmanager.pas
index 96a2938342..a4908d202a 100644
--- a/components/codetools/codetoolmanager.pas
+++ b/components/codetools/codetoolmanager.pas
@@ -394,6 +394,8 @@ type
           const NewSrc: string = ''): boolean; deprecated;
     function AddIncludeDirectiveForInit(Code: TCodeBuffer; const Filename: string;
           const NewSrc: string = ''): boolean;
+    function AddUnitWarnDirective(Code: TCodeBuffer; aParam: string;
+          TurnOn: boolean): boolean;
     function RemoveDirective(Code: TCodeBuffer; NewX, NewY: integer;
           RemoveEmptyIFs: boolean): boolean;
     function FixIncludeFilenames(Code: TCodeBuffer; Recursive: boolean;
@@ -3281,6 +3283,21 @@ begin
   end;
 end;
 
+function TCodeToolManager.AddUnitWarnDirective(Code: TCodeBuffer;
+  aParam: string; TurnOn: boolean): boolean;
+begin
+  Result:=false;
+  {$IFDEF CTDEBUG}
+  DebugLn(['TCodeToolManager.AddUnitWarnDirective A ',Code.Filename,' aParam="',aParam,'" TurnOn=',TurnOn]);
+  {$ENDIF}
+  if not InitCurCodeTool(Code) then exit;
+  try
+    Result:=FCurCodeTool.AddUnitWarnDirective(aParam,TurnOn,SourceChangeCache);
+  except
+    on e: Exception do Result:=HandleException(e);
+  end;
+end;
+
 function TCodeToolManager.RemoveDirective(Code: TCodeBuffer; NewX,
   NewY: integer; RemoveEmptyIFs: boolean): boolean;
 var
diff --git a/components/codetools/stdcodetools.pas b/components/codetools/stdcodetools.pas
index 5faea6374d..546efbb81c 100644
--- a/components/codetools/stdcodetools.pas
+++ b/components/codetools/stdcodetools.pas
@@ -280,6 +280,8 @@ type
     function AddIncludeDirectiveForInit(const Filename: string;
           SourceChangeCache: TSourceChangeCache; const NewSrc: string = ''
           ): boolean;
+    function AddUnitWarnDirective(WarnID: string; TurnOn: boolean;
+          SourceChangeCache: TSourceChangeCache): boolean;
     function FixIncludeFilenames(Code: TCodeBuffer;
           SourceChangeCache: TSourceChangeCache;
           out FoundIncludeFiles: TStrings;
@@ -6481,6 +6483,82 @@ begin
   Result:=true;
 end;
 
+function TStandardCodeTool.AddUnitWarnDirective(WarnID: string;
+  TurnOn: boolean; SourceChangeCache: TSourceChangeCache): boolean;
+const
+  DirectiveFlagValue: array[boolean] of string = ('on','off');
+var
+  ACleanPos, DirEndPos, InsertStartPos,
+    MaxPos: Integer;
+  Node: TCodeTreeNode;
+  p, IDStartPos, IDEndPos, ParamPos: PChar;
+  NewCode: String;
+begin
+  Result:=false;
+  if WarnID='' then
+    raise Exception.Create('TStandardCodeTool.AddUnitWarnDirective missing WarnID');
+  InsertStartPos:=0;
+  BuildTree(lsrMainUsesSectionStart);
+  SourceChangeCache.MainScanner:=Scanner;
+
+  MaxPos:=0;
+  Node:=Tree.Root.NextBrother;
+  if Node<>nil then
+    MaxPos:=Node.StartPos
+  else
+    MaxPos:=SrcLen;
+
+  // find existing directive for replacement
+  ACleanPos:=1;
+  repeat
+    ACleanPos:=FindNextCompilerDirective(Src,ACleanPos,Scanner.NestedComments);
+    if (ACleanPos<1) or (ACleanPos>MaxPos) then
+      break;
+    DirEndPos:=FindCommentEnd(Src,ACleanPos,Scanner.NestedComments)+1;
+    p:=@Src[ACleanPos+2];
+    if CompareIdentifiers(p,'warn')=0 then begin
+      IDStartPos:=p+4;
+      while IDStartPos^ in [' ',#9,#10,#13] do
+        inc(IDStartPos);
+      IDEndPos:=IDStartPos;
+      while IDEndPos^ in ['0'..'9','A'..'Z','a'..'z','_'] do
+        inc(IDEndPos);
+      if CompareText(PChar(Pointer(WarnID)),length(WarnID),
+                     IDStartPos,IDEndPos-IDStartPos,false)=0
+      then begin
+        // warn directive found
+        p:=IDEndPos;
+        while p^ in [' ',#9,#10,#13] do
+          inc(p);
+        ParamPos:=p;
+        while p^ in ['+','-','a'..'z','A'..'Z'] do
+          inc(p);
+        if not SourceChangeCache.Replace(gtSpace,gtNone,
+          ParamPos-PChar(Src)+1,p-PChar(Src)+1,DirectiveFlagValue[TurnOn])
+        then
+          exit;
+        Result:=SourceChangeCache.Apply;
+        exit;
+      end;
+    end else if (CompareIdentifiers(p,'i')=0) or (CompareIdentifiers(p,'include')=0)
+    then begin
+      // insert before include file
+      if MaxPos>ACleanPos then MaxPos:=ACleanPos;
+      break;
+    end;
+    ACleanPos:=DirEndPos;
+  until ACleanPos>MaxPos;
+
+  // there was no such directive yet -> find nice insert pos
+  InsertStartPos:=FindLineEndOrCodeInFrontOfPosition(MaxPos,true,true);
+  NewCode:='{$WARN '+WarnID+' '+DirectiveFlagValue[TurnOn]+'}';
+  if not SourceChangeCache.Replace(gtNewLine,gtNewLine,
+    InsertStartPos,InsertStartPos,NewCode)
+  then
+    exit;
+  Result:=SourceChangeCache.Apply;
+end;
+
 function TStandardCodeTool.FixIncludeFilenames(Code: TCodeBuffer;
   SourceChangeCache: TSourceChangeCache;
   out FoundIncludeFiles: TStrings;