Memory safe in D

[Richard (Rikki) Andrew Cattermole]

On 19/03/2024 1:31 AM, Nick Treleaven wrote:
> On Saturday, 16 March 2024 at 19:10:56 UTC, Don Allen wrote:
>> The compiler therefore forces you to handle the unusual case, so if it 
>> happens, the result will be something under your control.
> 
> You can call `unwrap` on the Option which will panic if it's None. But 
> that's fine, because that call makes it clear to anyone reading the code 
> that the programmer is intentionally assuming the Option contains a value.
> 
> ...
>> Related to the above, you may also process an uninitialized value, at 
>> which point anything can happen.
> 
> It can't violate memory safety:
> 
>> Void initializers for variables with a type that may contain unsafe 
>> values (such as types with pointers) are not allowed in @safe code.
> 
> https://dlang.org/spec/declaration.html#void_init

With type state analysis you should be allowed to write, but not read 
uninitialized variables.

So this restriction that it isn't @safe to use them in is simply because 
we don't have the ability to guarantee initialization before reading can 
occur.