let mut vec = vec![];
let mut x = 22;
vec.push(&x);
x += 1; // ERROR
drop(vec);
let mut vec: Vec<&'a u32> = Vec::new();
let tmp0: &'_ mut Vec<&'b u32> = &mut vec;
// subset('a, 'b) 'a: 'b
// subset('b, 'a) 'b: 'a
let tmp1: &'c u32 = &x; // Loan L0, 'c: {L0}
// ...
Vec::push(tmp0, tmp1); // (&mut Vec<T>, T), T = &'d u32
// 'c: 'b
// 'a: 'b // flows in from above
// 'b: 'a
// requires(L0, 'b)
// requires(L0, 'c)
// requires(L0, 'a) // transitive
x += 1; // error -- need L0 to be in scope
drop(vec); // live region: 'a, requires(L0, 'a)
let p = &x; // loan is created here
if foo {
vec.push(p); // connection between type of p and the type of vec is created here
x += 1; // ERROR
} else {
x += 1; // OK
}
fn unnecessary_error() {
vec-push-ref simplified
let mut vec = vec![];let mut x = 22;vec.push(&x);x += 1; // ERRORdrop(vec);let mut vec: Vec<&'a u32> = Vec::new();let mut x = 22;
let tmp0: &'_ mut Vec<&'b u32> = &mut vec; // subset('a, 'b) 'a: 'b // subset('b, 'a) 'b: 'alet tmp1: &'c u32 = &x; // Loan L0, 'c: {L0}// ...Vec::push(tmp0, tmp1); // (&mut Vec<T>, T), T = &'d u32 // 'c: 'b // 'a: 'b // flows in from above // 'b: 'a // requires(L0, 'b) // requires(L0, 'c) // requires(L0, 'a) // transitive
x += 1; // error -- need L0 to be in scopedrop(vec); // live region: 'a, requires(L0, 'a)vec-push-ref
let mut vec = vec![];let mut x = 22;let p = &x; // loan is created hereif foo { vec.push(p); // connection between type of p and the type of vec is created here x += 1; // ERROR} else { x += 1; // OK}drop(vec);unnecessary-error
fn unnecessary_error() {