[article] Language Design Deal Breakers

[deadalnix]

On Monday, 27 May 2013 at 21:55:00 UTC, Simen Kjaeraas wrote:
> Now, if we wanted to add compiler support for non-nullable 
> references, many
> more things would need to be decided - how do they look? Do 
> they assert
> non-nullness upon initialization/assignment, or are external 
> checks required?

Same problem exists with any type with @disable this.

> Does new Foo() return a non-nullable reference? Must we also 
> add scoped
> non-nullness guarantees (if(foo != null) { /* foo is now 
> implicitly
> convertible to non-nullable */ })?
>

if reference are non nullables, this example don't make any sense.

> So, no. The stuff required to add @disable this() to the 
> language is not the
> same that is required for non-nullable references. It's 
> certainly an important
> part of it, but there's still more left, and it's going to make 
> the language
> harder to implement. Adding a feature that lets non-nullable 
> references be
> added in a library is much better.

It is. Having everybody considering it isn't is probably why 
you'll find so much holes in NonNullable.