rust/tests/ui/reassign-ref-mut.rs
2023-01-11 09:32:08 +00:00

17 lines
615 B
Rust

// Tests how we behave when the user attempts to mutate an immutable
// binding that was introduced by either `ref` or `ref mut`
// patterns.
//
// Such bindings cannot be made mutable via the mere addition of the
// `mut` keyword, and thus we want to check that the compiler does not
// suggest doing so.
fn main() {
let (mut one_two, mut three_four) = ((1, 2), (3, 4));
let &mut (ref a, ref mut b) = &mut one_two;
a = &three_four.0;
//~^ ERROR cannot assign twice to immutable variable `a` [E0384]
b = &mut three_four.1;
//~^ ERROR cannot assign twice to immutable variable `b` [E0384]
}