Simplification of @trusted

[ag0aep6g]

On Thursday, 17 June 2021 at 17:42:08 UTC, Ola Fosheim Grøstad 
wrote:
> ```
> class A {
>
>     this() @trusted {
>         ptr = &buffer[0];
>         offset = 0;
>     }
>
>     int get() @trusted { return ptr[offset]; }
>     void set(int i) @trusted { this.offset = i&1; }
>
>     /*BUG: offset was pasted in here by mistake*/
>     int size()@safe{ offset=2;  return 2;}
>
> private:
>     int[2] buffer;
>     int* ptr;
>     int offset;
> }
>
>
> ```
>
> Since this @safe size() function could in theory mess up offset 
> by a bug, it should not be allowed?

With the current spec, the bug is in `get`. It cannot be 
@trusted, because it does not have a safe interface.

With DIP 1035 (@system variables) you could mark `offset` as 
@system. Then `get` would be fine and the compiler would catch 
the bug in `size`.

> However if we make size() @trusted then this is perfectly ok by 
> the requirements?

If you make `size` @trusted, `get` still does not have a safe 
interface and cannot be @trusted.