const BAD_BOOL: bool = unsafe { DummyUnion { u8: 42 }.bool};
//~^ ERROR it is undefined behavior to use this value
const UNINIT_BOOL: bool = unsafe { DummyUnion { unit: () }.bool};
-//~^ ERROR it is undefined behavior to use this value
+//~^ ERROR evaluation of constant value failed
+//~| uninitialized
// The value is not valid for any union variant, but that's fine
// unions are just a convenient way to transmute bits around