rust/tests/ui/mut/mut-pattern-internal-mutability.rs
2023-01-11 09:32:08 +00:00

16 lines
362 B
Rust

fn main() {
let foo = &mut 1;
let &mut x = foo;
x += 1; //~ ERROR cannot assign twice to immutable variable `x`
// explicitly mut-ify internals
let &mut mut x = foo;
x += 1;
// check borrowing is detected successfully
let &mut ref x = foo;
*foo += 1; //~ ERROR cannot assign to `*foo` because it is borrowed
drop(x);
}