On Saturday, 1 February 2014 at 20:03:40 UTC, Jonathan M Davis
wrote:
In the general case, you can only catch it at compile time if
you disallow it
completely, which is unnecessarily restrictive.
That is not accurate. The proposal here propose to make it
@system instead of disallowing it completely. Even looser, I
propose to make @system reference passing that can be null
through interface (function calls/return mostly). So you can use
null locally, where the compiler can check you do not dereference
it, and ensure that data coming from somewhere else is not null,
unless specified as such.
Sure, some basic cases can be
caught, but unless the code where the pointer/reference is
defined is right
next to the code where it's dereferenced, there's no way for
the compiler to
have any clue whether it's null or not. And yes, there's
certainly code where
it would make sense to use non-nullable references or pointers,
because
there's no need for them to be nullable, and having them be
non-nullable
avoids any risk of forgetting to initialize them, but that
doesn't mean that
nullable pointers and references aren't useful or that you can
catch all
instances of a null pointer or reference being dereferenced at
compile time.
- Jonathan M Davis
