src/test/ui/borrowck/issue-54499-field-mutation-of-never-init.rs

   1 // revisions: ast nll
   2
   3 // Since we are testing nll migration explicitly as a separate
   4 // revision, don't worry about the --compare-mode=nll on this test.
   5
   6 // ignore-compare-mode-nll
   7
   8 //[ast]compile-flags: -Z borrowck=ast
   9 //[nll]compile-flags: -Z borrowck=migrate -Z two-phase-borrows
  10
  11 #![warn(unused)]
  12 #[derive(Debug)]
  13 struct S(i32);
  14
  15 type Tuple = (S, i32);
  16 struct Tpair(S, i32);
  17 struct Spair { x: S, y: i32 }
  18
  19 fn main() {
  20     {
  21         let t: Tuple;
  22         t.0 = S(1);
  23         //[ast]~^ ERROR cannot assign to field `t.0` of immutable binding [E0594]
  24         //[nll]~^^ ERROR assign to part of possibly uninitialized variable: `t` [E0381]
  25         t.1 = 2;
  26         //[ast]~^ ERROR cannot assign to field `t.1` of immutable binding [E0594]
  27         println!("{:?} {:?}", t.0, t.1);
  28         //[ast]~^ ERROR use of possibly uninitialized variable: `t.0` [E0381]
  29         //[ast]~| ERROR use of possibly uninitialized variable: `t.1` [E0381]
  30     }
  31
  32     {
  33         let u: Tpair;
  34         u.0 = S(1);
  35         //[ast]~^ ERROR cannot assign to field `u.0` of immutable binding [E0594]
  36         //[nll]~^^ ERROR assign to part of possibly uninitialized variable: `u` [E0381]
  37         u.1 = 2;
  38         //[ast]~^ ERROR cannot assign to field `u.1` of immutable binding [E0594]
  39         println!("{:?} {:?}", u.0, u.1);
  40         //[ast]~^ ERROR use of possibly uninitialized variable: `u.0` [E0381]
  41         //[ast]~| ERROR use of possibly uninitialized variable: `u.1` [E0381]
  42     }
  43
  44     {
  45         let v: Spair;
  46         v.x = S(1);
  47         //[ast]~^ ERROR cannot assign to field `v.x` of immutable binding [E0594]
  48         //[nll]~^^ ERROR assign to part of possibly uninitialized variable: `v` [E0381]
  49         v.y = 2;
  50         //[ast]~^ ERROR cannot assign to field `v.y` of immutable binding [E0594]
  51         println!("{:?} {:?}", v.x, v.y);
  52         //[ast]~^ ERROR use of possibly uninitialized variable: `v.x` [E0381]
  53         //[ast]~| ERROR use of possibly uninitialized variable: `v.y` [E0381]
  54     }
  55 }