@trusted considered harmful

[Jonathan M Davis]

On Saturday, July 28, 2012 02:08:28 David Nadlinger wrote:
> This is similar to other constructs we have today, for example
> debug {}, which allows impure code. It can be debated whether a
> block »argument« should introduce a new scope or not (like
> static if). The latter currently seems much more attractive to
> me, but I suppose it could be confusing for some.

I'd definitely vote for it _not_ introducing a new scope. It will be much more 
useful that way.

> In any case, while there is probably quite a bit of bikeshedding
> to be done for 2), I don't think there is much controversy about
> 1). So, let's try to get this done shortly after the 2.060
> release – as discussed above, it is very unlikely that the
> change will break something, but the odds still increase over
> time. Also, there is currently a Phobos pull request [4] which
> will be influenced by the outcome of this discussion.

I'm all for this. Templates and @trusted just don't get along very well, which 
has a huge impact on ranges. The only real saving grace there is that 
attribute inferrence solves a lot of the problem if you just never use @safe 
or @trusted on a templated function, but when you have to do @system stuff 
within such a template, it's a real problem (as RefRange shows).

As for the syntax, I think that @trusted{ /+ at system code+/ } makes perfect 
sense.

- Jonathan M Davis