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Report From: Delphi-BCB/Compiler/Delphi/Language/Overloading/Method [ Add a report in this area ]

Report #: 3016

Status: Closed

Overloaded with different visibility method does not compile

Project: Delphi

Build #: 2195

Version: 6.0

Submitted By: Andrei Asayonak

Report Type: Minor failure / Design problem

Date Reported: 11/28/2002 8:33:26 AM

Severity: Infrequently encountered problem

Last Updated: 1/22/2006 10:40:52 AM

Platform: All versions

Internal Tracking #:

Resolution: Fixed (Resolution Comments)

Resolved in Build: : 10.0.2166

Duplicate of: None

Voting and Rating

Overall Rating: (6 Total Ratings)

4.17 out of 5

Total Votes: 1

Description

When a class's method is overloaded with different visibility:   ...
  public
    procedure CacheTable; overload; virtual;
  protected
    procedure CacheTable(tName : string); overload;
  ...

compiler generates "Undeclared identifier" error, if the method is called from outside the class.

I give this report Severity 1, because it may indicate some fundamental flaw in how ObjectPascal code is interpreted/generated.

Steps to Reproduce:

1. File-New-Application (for simplicity)
2. Add another unit
3. Adjust the generated form definition, so the files look like this:
//--------------------------------------------------------------------------------------------------------------------/
unit Unit1;
interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Contnrs, DBTables;

type
  TForm1 = class(TForm)
  private
  public
  end;

type

  TCachingObjectList = class (TObjectList)
  public
    TableName : string;

    constructor Create(tName : string);
    procedure CacheTable; overload; virtual;
  protected
    procedure CacheTable(tName : string); overload;
  end;

  TTaskInfoList = class (TCachingObjectList)
  public
    function getTaskInfo(taak_nr : string) : TObject;
  end;

var
  Form1: TForm1;
  TaskInfoList : TTaskInfoList;

implementation

{$R *.dfm}

{ TCachingObjectList }

procedure TCachingObjectList.CacheTable(tName: string);
begin
end;

procedure TCachingObjectList.CacheTable;
begin
  CacheTable(TableName);
end;

constructor TCachingObjectList.Create(tName: string);
begin
  inherited Create;
  TableName := tName;
end;

{ TTaskInfoList }

function TTaskInfoList.getTaskInfo(taak_nr: string): TObject;
begin
  result := nil;
end;

initialization
  TaskInfoList := TTaskInfoList.Create('aaa');
finalization
  TaskInfoList.Free;

end.

//--------------------------------------------------------------------------------------------------------------------/

unit Unit2;
interface

uses Unit1;

  procedure proc;

implementation

procedure proc;
begin
  //TaskInfoList.CacheTable;
end;

end.

//--------------------------------------------------------------------------------------------------------------------/

Note, the commented out text in Unit2.
This should compile with no problems.
4. Now go to Unit2 and uncomment the line. Code wont compile any more,  giving "Undeclared identifier:CacheTable" error.

Workarounds

This can be strange but it worked for me:

I moved the CacheTable overloaded method to the "public" section:
  ...
  public
    procedure CacheTable; overload; virtual;
    procedure CacheTable(tName : string); overload;
  protected
  ...

and code compiled with no problems. And then (!!!!!) I moved it back to the protected section,
  ...
  public
    procedure CacheTable; overload; virtual;
  protected
    procedure CacheTable(tName : string); overload;
  ...

and recompiled with no problems!

Attachment

None

Comments

Andrei Asayonak at 11/28/2002 8:35:34 AM -

Btw, Code completion displays the method in its pop-up list, so Code completion realisis I should be able to use it, but compiler does not.

Stefan Hoffmeister at 11/28/2002 11:18:17 AM -

Adjusted severity and type.

Robert Lee at 3/11/2003 5:34:34 AM -

Confirmed in D7

Kjell Rilbe at 5/27/2004 6:05:54 AM -

In some ways this sounds like it could be realted to 3077 "under the hood".

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