Safely wrapping an uncopyable struct to implement an interface

[Gregor Mückl via Digitalmars-d-learn]

Hi!

I've just created a situation in my code that is summarized by 
the following example. I don't know how to solve it with @safe 
code.

A third party library provides a struct that is not copyable:

// provided by third party
struct Foo {
    @disable this() @safe;
    @disable this(ref return scope Foo other) @safe;

    void magic() @safe;
}

What I want to do is to provide a safe wrapper around it that 
adapts to another interface:

// intended common interface
interface IWrapper {
    void bar() @safe;
}

Now, the obvious way to wrap this fails:

class FooWrapper : IWrapper {
    Foo f;

    this(Foo f) @safe {
        this.f = f; // this fails because it would be a copy
    }

    override void bar() @safe
    {
        f.magic();
    }
}

If Foo were a class, f would be a reference and everything would 
be fine. But f is a struct that can't be copied and taking a 
pointer to f makes FooWrapper obviously unsafe. How could I solve 
this?

I've come up with a workaround for my actual use case that 
doesn't need to use the uncopyable struct this way. But I'm 
curious if I'm missing something regarding references to structs.