Rust Lifetimes

rust_lifetimes.rs

struct Foo {
    x: i32,
}

struct Bar<'a> {
  foo: &'a Foo,
  // Uncomment to disallow drop()
  x: ::std::cell::RefCell<() /* Option<&'a Bar<'a>>*/>,
}

impl<'a> Bar<'a> {
    fn method(&'a self) { /* *self.x.borrow_mut() = Some(self)*/ }
    fn method2(&'a mut self) {}
}

fn main() {
  let foo = Foo {x: 10};
  let bar = Bar { foo: &foo, x: Default::default() };
  
  bar.method();
  //bar.method2();    // "cannot borrow immutable local variable `bar` as mutable"
  
  drop(bar);
}