Simplification of @trusted

[Andrei Alexandrescu]

On 2021-06-16 17:22, Walter Bright wrote:
> On 6/16/2021 6:09 AM, Sönke Ludwig wrote:
>> There are 800 of these in vibe.d alone.
> 
> That is concerning. But it isn't necessarily cause for redesigning 
> @trusted. For example, I removed (in aggregate) a great deal of unsafe 
> allocation code from the backend simply by moving all that code into one 
> resizable array abstraction.
> 
> Piece by piece, I've been removing the unsafe code from the backend. 
> There really should be very, very little of it.
> 
> 
>> There has also been an issue where the delegate workaround was 
>> erroneously flagged as a heap delegate, causing considerable GC memory 
>> load.
> 
> I can't think of a case where:
> 
> () @trusted { ... }();
> 
> would make it a heap delegate. Such cases should be in bugzilla.
> 
> 
>> `@trusted` *should* probably not even be available for functions (of 
>> course it is not a desirable breaking change to disallow that now, 
>> though).
> 
> The idea is to encourage programmers to think about organizing code so 
> that there are clear separations between safe and system code. 
> Interleaving the two on a line-by-line basis defeats the purpose.

I think the whole discussion should be redirected toward simplifying 
`pure` instead.

* There are many legitimate reasons to want impure code act as pure.
* There is no easy recourse as there is for @trusted. All approaches are 
crazily convoluted.