@trusted and return ref

[via Digitalmars-d-learn]

On Tuesday, 24 February 2015 at 22:49:17 UTC, w0rp wrote:
> In general, @trusted means "I have proven myself that this code 
> is actually safe, eeven though it uses unsafe features." The 
> compiler has to be pessimistic and assume that everything which 
> can be used unsafely will be used unsafely. @trusted, as it is 
> used here, is used to say, "I assure you I have used this in a 
> safe manner."

 From http://dlang.org/function.html#trusted-functions :

«Trusted functions are guaranteed by the programmer to not 
exhibit any undefined behavior if called by a safe function.»

I take this to mean that anything that is wrapped up in @trusted 
should not violate memory safety when in injected into any 
arbitrary context marked as @safe.

> I would like to see @trusted blocks, although I can see 
> Andrei's argument of not making it easy to do intentionally.

If @trusted is meant to be used the way he is doing it in this 
example then there is no reason to not provide @trusted-blocks. 
An inlined lambda is a block...

But it provides poor encapsulation and makes for weak typing.