[fpc-devel] Type+multi helpers overload bug

[Michael Van Canneyt]

On Sun, 8 May 2022, Hairy Pixels via fpc-devel wrote:

> Basically it looks like multi helpers don’t actually work with overloaded methods and simply choses the last helper declared. Should I fix this? Seems unlikely we would not notice this before but maybe we did.
>
> {$modeswitch typehelpers}
> {$modeswitch multihelpers}
>
> type
>  TMyHelper1 = type helper for integer
>    procedure DoThis(f: integer);
>  end;
>  TMyHelper2 = type helper for integer
>    procedure DoThis(f: string);
>  end;
>
> procedure TMyHelper1.DoThis(f: integer);
> begin
>  writeln(self, ' => ', f);
> end;
>
> procedure TMyHelper2.DoThis(f: string);
> begin
>  writeln(self, ' => ', f);
> end;
>
> var
>  i: integer = 0;
> begin
>  i.DoThis(0);  // Got "ShortInt", expected “ShortString"

If you fix this, then I think you should make sure it is only done when the
overload; keyword is present. For regular classes, searching for an overload match 
stops also at the current class (? unit) if the overload keyword is not present.

Michael.