[fpc-pascal] Array issue

[Guillermo Martínez Jiménez]

Hi,

tested your code on Debian 13 + fpc 3.2.2 and had the same output than
you.

I've added another test:

~~~
  y := x + [234, 567] + [0, 0];
{ prints [0,0,0,0,0,0] }
  for i := Low(y) to High(y) do writeln (y[i]);
~~~

Prints [0,0,0,0,0,0] but shouldn't it be [0,0,234,567,0,0]?

Regards,
Guillermo "Ñuño" Martínez.

El Mon, 15 Jun 2026 11:00:41 +0200
Thomas Kurz via fpc-pascal <fpc-pascal at lists.freepascal.org> escribió:
> Dear all,
> 
> I'm observing a strange array issue. Please consider this code:
> 
> ```
> program ArrayTest;
> 
> {$MODESWITCH ARRAYOPERATORS}
> 
> var x, y: packed array of PtrInt; i: Integer;
> 
> begin
>   x := [0,0];
> 
>   y := System.Copy (x, 0, Length(x)-2) + [234, 567] + [0, 0];
>   // prints [0,0,0,0]
>   for i := Low(y) to High(y) do writeln (y[i]);
> 
>   y := System.Copy (x, 0, Length(x)-2);
>   y := y + [234, 567];
>   y := y + [0, 0];
>   // prints [234,567,0,0]
>   for i := Low(y) to High(y) do writeln (y[i]);
> end.
> ```
> 
> To me, both assignments to `y` are equal in the end. But the first
> one results in `y = [0,0,0,0]`, while the second one correctly gives
> me `y = [234,567,0,0]`.
> 
> I'm on Windows 64, trunk 3.3.1 (Free Pascal Compiler version 3.3.1
> [2026/03/11] for x86_64) and would appreciate if anyone could try to
> reproduce this behavior. Or explain it to me :)
> 
> Kind regards,
> Thomas
> 
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