src/test/ui/consts/const-eval/validate_uninhabited_zsts.rs

   1 // stderr-per-bitwidth
   2
   3 const fn foo() -> ! {
   4     unsafe { std::mem::transmute(()) }
   5     //~^ ERROR evaluation of constant value failed
   6     //~| WARN the type `!` does not permit zero-initialization [invalid_value]
   7 }
   8
   9 // Type defined in a submodule, so that it is not "visibly"
  10 // uninhabited (which would change interpreter behavior).
  11 pub mod empty {
  12     #[derive(Clone, Copy)]
  13     enum Void {}
  14
  15     #[derive(Clone, Copy)]
  16     pub struct Empty(Void);
  17 }
  18
  19 #[warn(const_err)]
  20 const FOO: [empty::Empty; 3] = [foo(); 3];
  21
  22 #[warn(const_err)]
  23 const BAR: [empty::Empty; 3] = [unsafe { std::mem::transmute(()) }; 3];
  24 //~^ ERROR it is undefined behavior to use this value
  25 //~| WARN the type `empty::Empty` does not permit zero-initialization
  26
  27 fn main() {
  28     FOO;
  29     BAR;
  30 }