trait Foo {
  fn get<'a, 'b: 'a> (self: &'a Self) -> Option<&'b str>;
  fn insert (self: &mut Self, _: String);
}

fn bar (foo: &mut Foo) // works !
{
  if let Some(s_ref) = foo.get() {
    return println!("{}", s_ref)
  }
  foo.insert(42.to_string());
  bar(foo)
}

fn bad (foo: &mut Foo) // error
{
  if let Some(s_ref) = foo.get() {
    println!("{}", s_ref)
  } else {
    // idea: None: Option<&'mut_borrow_lt str> here explains the error
    foo.insert(42.to_string());
    bad(foo)
  }
}

fn bad_unsugared (foo: &mut Foo) // error
{
  match foo.get() {
    Some(s_ref) => println!("{}", s_ref),
    _ => {// idea: None: Option<&'mut_borrow_lt str> here explains the error
      foo.insert(42.to_string());
      bad_unsugared(foo)
    },
  }
}

fn baz<'a, 'b: 'a>(foo: &'a mut Foo) -> &'b str // error??? why?
{
  if let Some(s_ref) = foo.get() {
    return s_ref
  }
  // idea ??
  foo.insert(42.to_string());
  foo.get().unwrap()
}

fn main () {}