Delphi Compiler Error
E2568 Can’t create new instance without CONSTRUCTOR constraint in type parameter declaration
Reason for the Error & Solution
This occurs when the generic type is derived from a class that has an implicit constructor and the default constructor clause is not mentioned.
program E2568;
{$APPTYPE CONSOLE}
uses
SysUtils;
type
TMyClass1 = class
end;
TMyClass2<T: TMyClass1> = class // Fix: replace < T : TmyClass1> with <T : TMyClass1, constructor>
public
procedure Add;
end;
procedure TMyClass2<T>.Add;
begin
T.Create(nil); //E2568
end;
begin
Writeln('E2568 Cannot create new instance without CONSTRUCTOR constraint in type parameter declaration');
end.
