On 08/11/2018 10:55 PM, Eric wrote:
Code below compiles while I would not expect it to compile.
Is there a reason that this compiles?
[...]
class I {
abstract void f();
}
class C : I {
}
unittest {
C c = cast(C) Object.factory("C");
c.f();
}
Not a bug, as far as I see.
You don't get compile-time errors with Object.factory. It works at run
time, on dynamic values (e.g., a class name entered on the command
line). You're calling it with a constant string, but the compiler
doesn't care about that. There's no special handling for that.
Object.factory returns `null` when it can't create the object. And it
does that in your example, because of the abstract method (and because
"C" is wrong; the name must be fully qualified). You're supposed to
check for `null` before attempting to use the object.
If you want a compile-time check, don't use Object.factory. Use `new`
instead:
C c = new C; /* Error: cannot create instance of abstract class C */
