File: reassign-ref-mut.rs

package info (click to toggle)
rustc-web 1.78.0%2Bdfsg1-2~deb12u3
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 1,245,420 kB
  • sloc: xml: 147,985; javascript: 18,022; sh: 11,083; python: 10,265; ansic: 6,172; cpp: 5,023; asm: 4,390; makefile: 4,269
file content (16 lines) | stat: -rw-r--r-- 615 bytes parent folder | download | duplicates (18)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
// 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]
}