Current sentiment on Nullable.get

[Steven Schveighoffer]

On 12/10/18 5:01 AM, FeepingCreature wrote:
> Having recently been reminded that `alias Nullable.get this` exists, I'm 
> considering a pull request to deprecate it. What's the sentiment on 
> `alias Nullable.get this` in the community? My unchanged stance is that 
> it's a blight and an interminable source of impossible to find runtime 
> bugs, and an anti-feature that misses the point of Nullable to provide 
> safe optional types.
> 
> The typical problem goes like this:
> 
> 1. A dependency switches from T to Nullable!T.
> 2. You update your dependencies.
> 3. Your program still compiles (because Nullable!T silently casts to "T 
> or exception") and you notice nothing.
> 4. Sometime later, your program crashes in production.

Wow, I didn't realize that get, in production with asserts off, is no 
different than just any T. It's practically useless.

I don't think we can simply deprecate that feature. All you will see is 
people adding "get" to all the accesses, but still resulting in the same 
problem.

I was going to suggest changing the assert to an enforce, but that 
changes the nothrow semantics.

I think we'd be better off adding a new type, which does what people 
want, and deprecating Nullable completely.

-Steve