Calling a Class Constructor

[Handoko]

Someone asked me why the syntax analyzer accepts the line #10, there were no compile error, warning, nor hint. I don't know. Can anyone please provide an explanation?
https://forum.lazarus.freepascal.org/index.php/topic,57604.msg428688.html#msg428688

Code: Pascal  [Select][+][-]

1. type
2.   TNumber = class
3.     // ...
4.   end;
5.  
6. procedure TForm1.Button1Click(Sender: TObject);
7. var
8.   N1: TNumber;
9. begin
10.   N1.Create;
11. end;

[PascalDragon]

Someone asked me why the syntax analyzer accepts the line #10, there were no compile error, warning, nor hint. I don't know. Can anyone please provide an explanation?

A constructor is called like a normal method if called on an instance variable or within an instance (e.g. if you call another constructor of the same class within the class' constructor it's called as a normal method). Of course this leads to trouble if the instance was never created like in your example. (And yes, it's a common mistake and sometimes even happens to experienced Object Pascal developers )

[dseligo]

A constructor is called like a normal method if called on an instance variable or within an instance (e.g. if you call another constructor of the same class within the class' constructor it's called as a normal method). Of course this leads to trouble if the instance was never created like in your example. (And yes, it's a common mistake and sometimes even happens to experienced Object Pascal developers )

It would be great if there is a warning, something like: Variable 'N1' does not seem to be initialized.