Temporary @trusted scope

[Jonathan M Davis]

On Tuesday, December 18, 2018 3:14:50 AM MST Per Nordlöw via Digitalmars-d-
learn wrote:
> What's the preferred way of creating a temporary @trusted scope
> without writing a separate  function?
>
> Similar to Rust's
>
> unsafe { /* unsafe stuff here */ }

Unfortunately, D does not currently have a way to do that. Only functions
can be marked with @trusted. However, the typical approach to this problem
is to use a lambda, which is more or less syntactically the same except that
it has some extra parens. e.g.

() @trusted { doUnsafe(); }();

or

auto result = () @trusted { getUnsafe:() }();

So, it's less than ideal, but it gets us close, and unless the code is long
enough that maybe it should be in its own function, it's better than
declaring a nested function, let alone declaring an entirely separate
function at module scope.

- Jonathan M Davis