How to inline static array variables in Rio

Question

I am failing to inline constructs such as

var FileName: array[0..2047] of Char;

This works:

procedure TForm1.AcceptFiles(var Msg: TWMDropFiles);
var FileName: array[0..2047] of Char;
begin
  DragQueryFile(msg.Drop, $FFFFFFFF, FileName, 2048);
  ...
end;

But this fails if FileName is inlined:

procedure TForm1.AcceptFiles(var Msg: TWMDropFiles);
begin
  var FileName: array[0..2047] of Char; // E2029 Expression expected but array found
  DragQueryFile(msg.Drop, $FFFFFFFF, FileName, 2048);
  ...
end;

I managed to inline 12K of variables of any kind, but it seems like anything of the below form can not be inlined:

begin
  var Name: array[X..Y] of Z;
end;

Please advice how it is done in Rio 10.3.3.

QC Ticket opened at: https://quality.embarcadero.com/browse/RSP-31970 — Gad D Lord, Dec 19 '20 at 02:18
Previous inline var tickets already resolved are: https://quality.embarcadero.com/browse/RSP-21925, https://quality.embarcadero.com/browse/RSP-22036, https://quality.embarcadero.com/browse/RSP-22113, https://quality.embarcadero.com/browse/RSP-21680 — Gad D Lord, Dec 19 '20 at 02:18
does the problem go away if you define the array type beforehand? `type TFileNameArr = array[0..2048] of Char; var FileName: TFileNameArr;` — Remy Lebeau, Dec 19 '20 at 05:33
BTW, you are passing 2048 to the API, but the array has length 2049. — David Heffernan, Dec 19 '20 at 08:48
@RemyLebeau it works. procedure Proc1; const MAX_FILENAME_LEN = 2048; typeTFileNameArray = array[0..MAX_FILENAME_LEN - 1] of Char; begin var FileName: TFileNameArray; DragQueryFile(Msg.Drop, $FFFFFFFF, FileName, MAX_FILENAME_LEN); Please feel free to submit as answer so I can approve. — Gad D Lord, Dec 19 '20 at 10:01
Perhaps inline variable declaration of arrays follows the same rules as [procedural parameters](http://docwiki.embarcadero.com/RADStudio/en/Parameters_(Delphi)#Array_Parameters): *When you declare routines that take array parameters, you cannot include index type specifiers in the parameter declarations.* — LU RD, Dec 19 '20 at 11:23

score 2 · Accepted Answer · answered Dec 23 '20 at 23:28

As @Remy Lebeau rightfully suggested the solution is to declare the type first

procedure TForm1.AcceptFiles(var Msg: TWMDropFiles);
type
  TFileNameArray = array[0..2047] of Char;
begin
  var FileName: TFileNameArray;
  DragQueryFile(msg.Drop, $FFFFFFFF, FileName, 2048);
  ...
end;

How to inline static array variables in Rio

1 Answers1