On Borrow Checking

[Walter Bright]

On 5/12/2025 5:34 AM, Timon Gehr wrote:
> Even in `@system` code you cannot assign an `int` to an `int*`, you have to use 
> an explicit cast. I don't think it is true that just because `@system` does not 
> give you memory safety guarantees it will therefore be expected that features do 
> not work at all.

@system code is intended to be rare in a properly written D program. 
Unfortunately, D code is not @safe by default. We are moving to @safe by 
default, but that requires the editions feature.

Where the line is drawn for what is allowed in @system code is a judgement call, 
not an obvious thing. Requiring `scope` to be transitive across existing default 
code would discourage people from using it.

Again, I'll point out all the complaints about @nogc being transitive and 
thereby making it difficult to use in existing code.