[fpc-pascal] Verify Method Calls

[tobiasgiesen at gmail.com]

Hello,
many thanks for your reply! -vh didn't show more info, but I was able to
reduce the source to a small program, maybe you can try it? Compiling it
with -CR fails, but without it compiles fine without warnings.
Unfortunately there are many typecasts like these and I don't know how
to solve it.
Best wishes,
Tobias Giesen

-----------------
program AnInterfaceTest;

uses Classes;

type
  {** Replacement for generic interface type. }
  IZInterface = IUnknown;

  {** Represents an interface for all abstract object. }
  IZObject = interface(IZInterface)
    ['{EF46E5F7-00CF-4DDA-BED0-057D6686AEE0}']
    function Clone: IZInterface;
  end;

  {** Represents an interface to clone objects. }
  IZClonnable = interface(IZObject)
    ['{ECB7F3A4-7B2E-4130-BA66-54A2D43C0149}']
  end;

  {** Represents a collection of object interfaces. }
  IZCollection = interface(IZClonnable)
    ['{51417C87-F992-4CAD-BC53-CF3925DD6E4C}']
  end;

  {** Represents a hash map interface. }
  IZHashMap = interface(IZClonnable)
    ['{782C64F4-AD09-4F56-AF2B-E4193A05BBCE}']
  end;

  {** Implements an abstract interfaced object. }

  { TZAbstractObject }

  TZAbstractObject = class(TInterfacedObject, IZObject)
  public
    function Clone: IZInterface; virtual;
  end;

  { TZHashMap }

  TZHashMap = class(TZAbstractObject, IZHashMap, IZClonnable)
  private
    FKeys: IZCollection;
  public
    constructor Create;
    destructor Destroy; override;

    function Clone: IZInterface; override;
  end;

{ TZAbstractObject }

function TZAbstractObject.Clone: IZInterface;
begin
  result := nil; // needs to be overriden
  end;

{ TZHashMap }

constructor TZHashMap.Create;
begin

end;

destructor TZHashMap.Destroy;
begin
 inherited Destroy;
end;

function TZHashMap.Clone: IZInterface;
var
  HashMap: TZHashMap;
begin
  HashMap := TZHashMap.Create;

  HashMap.FKeys := IZCollection(FKeys.Clone);
  Result := HashMap;
end;

begin
end.

-----------------

Kind Regards,

Tobias Giesen

----

On Mon, 4 Jul 2016 22:55:19 +0200
Jonas Maebe <jonas.maebe at elis.ugent.be> wrote:

> On 04/07/16 19:38, tobiasgiesen at gmail.com wrote:
> > I would like to use "Verify Method Calls" (-CR), but when I choose it in the Lazarus
> > project options under debugging, I get compiler errors such as:
> >
> > Incompatible type for arg no.2: Got "Class Of IZCollection", expected "TClass".
> >
> > With Verify Method Calls off, the same code compiles fine.
> >
> > The offending line is from ZEOS lib, ZCollections.pas:
> >
> > HashMap.FKeys := IZCollection(FKeys.Clone);
> >
> > I wonder why it says "arg no.2".
> 
> Try compiling with -vh, it may show more info. -CR basically turns all object/class typecasts into "as"-like expressions, but in a way that you can still pass them to var/out-parameters.
> 
> > Is it possible to turn "Verify Method Calls" off via a {$xxx } switch in the
> > source code?
> 
> No.
> 
> 
> Jonas
> _______________________________________________
> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
> http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal

Kind Regards,
Tobias Giesen

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