False-positive note "Local variable is assigned but never used"

Summary

FPC complains project1.lpr(11,3) Note: Local variable "ErrorType" is assigned but never used for the following code, although this variable is actually used.

Duplicate of #26002?

System Information

• Operating system: Windows 7 Ultimate x64
• Processor architecture: x86-64
• Compiler version: 3.2.2
• Device: Computer

Example Project

program Project1;

{$MODE OBJFPC}

uses SysUtils;

// NB: be careful, there's already a typed const ErrorCode in systemh.inc
// {$WRITEABLECONST OFF} doesn't help as it impacts only the constant itself, not the usage of it

var
  ErrorType: TClass;
  ErrorCode: LongInt;

begin
  try
    WriteLn('kek');
  except on E: TObject do
    begin
      if E is Exception then
      begin
        // gather some additional info from all standard descendants known
        if E is EVariantError then ErrorCode := EVariantError(E).ErrCode
        else if E is EInOutError then ErrorCode := EInOutError(E).ErrorCode
        else if E is EOSError then ErrorCode := EOSError(E).ErrorCode;

        WriteLn(ErrorCode);
        ErrorType := Exception;
      end
      else
      begin
        ErrorType := TObject;
      end;

      // also write string representation if available (check if method is overridden)
      if @E.ToString <> @ErrorType.ToString then  // <-- using ErrorType here
        WriteLn(E.ToString());
    end;
  end;
end.

Relevant logs and/or screenshots

\project1>C:\Lazarus\fpc\3.2.2\bin\x86_64-win64\fpc Project1.lpr
Free Pascal Compiler version 3.2.2 [2025/07/19] for x86_64
Copyright (c) 1993-2021 by Florian Klaempfl and others
Target OS: Win64 for x64
Compiling Project1.lpr
Project1.lpr(11,3) Note: Local variable "ErrorType" is assigned but never used
Linking Project1.exe
40 lines compiled, 0.2 sec, 72704 bytes code, 5252 bytes data
1 note(s) issued