Delphi Pascal XE4 Compiler bug? - delphi

Question

I wonder if I have found an Embarcadero compiler bug ...
The problem looks like it is related to generics.
Here is my source code
unit u_DateCount;
interface
uses
SysUtils,
u_JavaScriptable
;
type
TDateCount = class (TJavaScriptable)
strict private
public
NoOfSamples : Integer;
TheDate : TDate;
function ToString():String; override;
end;
implementation
function TDateCount.ToString():String;
var
myYear, myMonth, myDay : Word;
begin
DecodeDate(TheDate, myYear, myMonth, myDay);
Result := Format('[new Date(%d, %d ,0), %d]', [myYear, myMonth, NoOfSamples]);
end;
end.
unit u_Javascriptable;
interface
type
TJavaScriptable = class
strict private
public
function ToString:String; override;
end;
implementation
function TJavaScriptable.ToString:String;
begin
Result := '';
end;
end.
unit u_LineChart;
interface
uses
System.IOUtils,
SysUtils,
System.Generics.Collections,
u_JavaScriptable
;
type
TLineChart<RecordType : TJavaScriptable> = class
strict private
Template : String;
function ConvertRecordsToString():String;
public
Records : TList<RecordType>;
function ToString():String;
constructor Create(templatePath : String);
destructor Destroy(); override;
end;
implementation
function TLineChart<RecordType>.ConvertRecordsToString():String;
var
I: Integer;
begin
//Open brackets
Result := '[ ';
//The first record
if Records.Count > 0 then
begin
Result := Result + Records[0].ToString();
end;
//Loop over records
for I := 1 to Records.Count - 1 do
begin
Result := Result + ', ' + Records[I].ToString();
end;
//Close bracket
Result := Result + ' ]';
end;
function TLineChart<RecordType>.ToString():String;
begin
Result := Format(Template, [ConvertRecordsToString()]);
end;
constructor TLineChart<RecordType>.Create(templatePath : String);
begin
inherited Create();
Template := TFile.ReadAllText(templatePath);
Records := TList<RecordType>.Create();
end;
destructor TLineChart<RecordType>.Destroy();
var
I: Integer;
begin
if Assigned(Records) then
begin
for I := 0 to Records.Count - 1 do
begin
Records[I].Destroy();
end;
Records.Clear();
Records.Destroy();
Records := nil;
end;
inherited;
end;
end.
And finally the main program
program Project4;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils,
u_Javascriptable in 'u_Javascriptable.pas',
u_LineChart in 'u_LineChart.pas',
u_DateCount in 'u_DateCount.pas';
var
lineChart : TLineChart<TDateCount>;
begin
lineChart := TLineChart<TDateCount>.Create('linechart.html');
try
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
end.
The error message I get when I try to compile this is
[dcc32 Fatal Error] Project4.dpr(30): F2084 Internal Error:
AV097530AC-R00000014-0
Usually when I see an error message similar to this, I can fix it by closing the embarcadero IDE and restarting it. However this did not seem to work this time.

Answer 1

The problem is in the implementation of TLineChart<RecordType>.Destroy().
Change Records[I].Destroy(); to Records[I].Free(); and it works.
Or you just do it correct and use TObjectList<RecordType>.Create; in the constructor which takes care of destroying all elements in it when destroying the list.
Never call Destroy directly. Use Free. While it should not result in a compiler error it is wrong anyway.

Answer 2

If the compiler reports an "internal error," that's always a compiler bug. You should open a ticket in QC for this. Hopefully they can get it fixed for XE5.

Answer 3

Since this works in XE3 but not XE4, I'm going to presume this is an XE4 bug. Until this is fixed, the solution is to use a different version of the compiler such as XE3.