tests/ui/binding/issue-53114-safety-checks.rs

   1 // Issue #53114: NLL's borrow check had some deviations from the old borrow
   2 // checker, and both had some deviations from our ideal state. This test
   3 // captures the behavior of how `_` bindings are handled with respect to how we
   4 // flag expressions that are meant to request unsafe blocks.
   5
   6 #[derive(Copy, Clone)]
   7 struct I(i64);
   8 #[derive(Copy, Clone)]
   9 struct F(f64);
  10
  11 union U { a: I, b: F }
  12
  13 #[repr(packed)]
  14 struct P {
  15     a: &'static i8,
  16     b: &'static u32,
  17 }
  18
  19 fn let_wild_gets_unsafe_field() {
  20     let u1 = U { a: I(0) };
  21     let u2 = U { a: I(1) };
  22     let p = P { a: &2, b: &3 };
  23     let _ = &p.b;  //~ ERROR    reference to packed field
  24     let _ = u1.a;  //~ ERROR  [E0133]
  25     let _ = &u2.a; //~ ERROR  [E0133]
  26
  27     // variation on above with `_` in substructure
  28     let (_,) = (&p.b,);  //~ ERROR     reference to packed field
  29     let (_,) = (u1.a,);  //~ ERROR   [E0133]
  30     let (_,) = (&u2.a,); //~ ERROR   [E0133]
  31 }
  32
  33 fn let_ascribe_gets_unsafe_field() {
  34     let u1 = U { a: I(0) };
  35     let u2 = U { a: I(1) };
  36     let p = P { a: &2, b: &3 };
  37     let _: _ = &p.b;  //~ ERROR    reference to packed field
  38     let _: _ = u1.a;  //~ ERROR  [E0133]
  39     let _: _ = &u2.a; //~ ERROR  [E0133]
  40
  41     // variation on above with `_` in substructure
  42     let (_,): _ = (&p.b,);  //~ ERROR     reference to packed field
  43     let (_,): _ = (u1.a,);  //~ ERROR   [E0133]
  44     let (_,): _ = (&u2.a,); //~ ERROR   [E0133]
  45 }
  46
  47 fn match_unsafe_field_to_wild() {
  48     let u1 = U { a: I(0) };
  49     let u2 = U { a: I(1) };
  50     let p = P { a: &2, b: &3 };
  51     match &p.b  { _ => { } } //~ ERROR     reference to packed field
  52     match u1.a  { _ => { } } //~ ERROR   [E0133]
  53     match &u2.a { _ => { } } //~ ERROR   [E0133]
  54
  55     // variation on above with `_` in substructure
  56     match (&p.b,)  { (_,) => { } } //~ ERROR     reference to packed field
  57     match (u1.a,)  { (_,) => { } } //~ ERROR   [E0133]
  58     match (&u2.a,) { (_,) => { } } //~ ERROR   [E0133]
  59 }
  60
  61 fn main() { }