Hi,

the following unit throws an (I think wrong) compile error "Duplicate identifier 'Connection'". This happens Lazarus with 2.0.8 under Win 10 (64). According to Nicklaus Wirth and Kathleen Jensen ('Pascal User Manual and Report') there is no duplicate  identifier in this  unit, since 'Connection' in procedure Proc ist strictly local and does not interfere with Identfiers outside this procedure.

Code:

unit DoubleDefinition;
{$mode objfpc}{$H+}
interface
  uses
   Classes, SysUtils, sqlite3conn, Forms, Controls, Graphics, Dialogs;
  type
    { TForm1 }
    TForm1 = class(TForm)
     Connection: TSQLite3Connection;
     procedure Proc;
   end;
var Form1: TForm1;
implementation
{$R *.lfm}
procedure TForm1.Proc;
var Connection: TSQLite3Connection;
begin
   Connection:=  TSQLite3Connection.Create(Form1);
   Connection.Free;
end;
end.

Regards --  Joe

You are aware, that this manual was way before Object Pascal?

Code: unit DoubleDefinition; {$mode objfpc}{$H+}

$mode objfpc is more strict on duplicates.
FPC supports other modes like $mode Delphi, which allows this duplicate.

Mattias

Here there is no Duplicate Identifier error message:

program Duplicate;
{$mode objfpc}{$H+}
var TestVar: string;
procedure Proc;
var TestVar: string;
begin
   TestVar:= 'zwei';
   writeln (TestVar)
end;
begin
   TestVar:= 'eins';
   writeln (TestVar);
   Proc
end.

Why this inconsistency?

Regards --  Joe

There is no inconsistency: there is no object.

An object in some way represents a single scope of identifiers. In that sense, it makes sense to forbid duplicates. It's a thin line.

In practice, I find that the objfpc mode is less error prone than the Delphi mode. I had some nasty surprises in the past in Delphi with duplicate names in methods and properties.

Michael.

Michael.

Thanks for the clarification.
--  J o e