use std::mem;

use std::mem::{self, ManuallyDrop};

    inner: Box<ErrorImpl<()>>,

    inner: ManuallyDrop<Box<ErrorImpl<()>>>,

            object_drop: object_drop::<E>,

        Error {
            inner: mem::transmute::<Box<ErrorImpl<E>>, Box<ErrorImpl<()>>>(inner),
        }

        let erased = mem::transmute::<Box<ErrorImpl<E>>, Box<ErrorImpl<()>>>(inner);
        let inner = ManuallyDrop::new(erased);
        Error { inner }

        unsafe { ptr::drop_in_place(self.inner.error_mut()) }

        unsafe {
            let inner = ptr::read(&mut self.inner);
            let erased = ManuallyDrop::into_inner(inner);
            (erased.vtable.object_drop)(erased);
        }

    object_drop: unsafe fn(Box<ErrorImpl<()>>),

}
unsafe fn object_drop<E>(e: Box<ErrorImpl<()>>) {
    // Cast back to ErrorImpl<E> so that the allocator receives the correct
    // Layout to deallocate the Box's memory.
    let unerased = mem::transmute::<Box<ErrorImpl<()>>, Box<ErrorImpl<E>>>(e);
    drop(unerased);