[fpc-devel] Feature announcement: Generic type constraints

[Marco van de Voort]

In our previous episode, Sven Barth said:
> 
> I'm pleased to announce the addition of generic type constraints to Free 
> Pascal (beginning from revision 23158).

Just FYI, last week I noticed Delphi isn't terribly succesful in working with
constraints in combination with forward defines:

{$apptype console}
uses generics.collections;

type
  TLockedPool<t:class,constructor> = class
                                         end;
  TSerialCommand= class;
  TSerialCommandPool = TLockedpool<TSerialCommand>;
  TSerialCommand= class
                  name : string;
                  pool : TSerialCommandPool;
                  public
                  constructor create;
                  // procedure releasetopool;
                end;

                  constructor tserialcommand.create;
begin
end;

begin
end.

Embarcadero Delphi for Win32 compiler version 24.0
Copyright (c) 1983,2012 Embarcadero Technologies, Inc.
sometest.dpr(8) Error: E2513 Type parameter 't' must have one public
parameterless constructor named Create
sometest.dpr(21)