Implementation mutable reference question

[hpless]

impl MyThing{
    fn test_borrow(&mut self){
        println!("OwO {}", self.name);
    }
}

  let a = MyThing{...};
  a.test_borrow();

In this code, a can't be mutated so the compiler rightly complained to me.

impl Drop for MyThing{
    fn drop(&mut self){
        println!("Dropping {}", self.name);
    }
}

But if I implement Drop for MyThing, the funcitno signature uses "&mut". The compiler didn't complain, and the program actually ran to finished and drop was called.

Am I missing something? Is Drop special?

[bluss]

Drop is a bit special. But remember that the owner decides about mutability.

You can change your example to:

let a = MyThing{...};
{
    let mut b = a;
    b.test_borrow();
}

And it's ok. And even this!

let a = MyThing{...};
{a}.test_borrow();

(Hint: the variable a no longer owns the MyThing value, it becomes a temporary)

[hpless]

I see how drop is special, and we are not allowed to directly call it anyway. That makes sense. Thank you for your explanation.