[phobos] phobos commit, revision 1534

[SHOO]

Do you mean that don't mark @trusted without thought, and should mark 
@system if it have any risk? (For example, precision loss for cast, or 
pointer operation)

Andrei Alexandrescu さんは書きました:
> I think we should exercise extra caution in applying @trusted to 
> templates. For example, without having thought much about it, I suspect 
> many functions and structures in std.algorithm could be used in ways 
> that make them unsafe.
> 
> Andrei
>