src/test/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 #![feature(untagged_unions)]
   7
   8 struct I(i64);
   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;  //~ WARN    E0133
  24     //~^  WARN will become a hard error
  25     let _ = u1.a;  // #53114: should eventually signal error as well
  26     let _ = &u2.a; //~ ERROR  [E0133]
  27
  28     // variation on above with `_` in substructure
  29     let (_,) = (&p.b,);  //~ WARN     E0133
  30     //~^  WARN will become a hard error
  31     let (_,) = (u1.a,);  //~ ERROR   [E0133]
  32     let (_,) = (&u2.a,); //~ ERROR   [E0133]
  33 }
  34
  35 fn match_unsafe_field_to_wild() {
  36     let u1 = U { a: I(0) };
  37     let u2 = U { a: I(1) };
  38     let p = P { a: &2, b: &3 };
  39     match &p.b  { _ => { } } //~ WARN     E0133
  40     //~^  WARN will become a hard error
  41     match u1.a  { _ => { } } //~ ERROR   [E0133]
  42     match &u2.a { _ => { } } //~ ERROR   [E0133]
  43
  44     // variation on above with `_` in substructure
  45     match (&p.b,)  { (_,) => { } } //~ WARN     E0133
  46     //~^  WARN will become a hard error
  47     match (u1.a,)  { (_,) => { } } //~ ERROR   [E0133]
  48     match (&u2.a,) { (_,) => { } } //~ ERROR   [E0133]
  49 }
  50
  51 fn main() { }