// This is the first counter-example from Niko's blog post // smallcultfollowing.com/babysteps/blog/2017/03/01/nested-method-calls-via-two-phase-borrowing/ // of a danger for code to crash if we just turned off the check for whether // a mutable-borrow aliases another borrow. fn main() { let mut v: Vec<String> = vec![format!("Hello, ")]; v[0].push_str({ v.push(format!("foo")); //~^ ERROR cannot borrow `v` as mutable more than once at a time [E0499] "World!" }); }