tests/ui/consts/const-eval/issue-50814-2.rs

   1 // build-fail
   2
   3 trait C {
   4     const BOO: usize;
   5 }
   6
   7 trait Foo<T> {
   8     const BAR: usize;
   9 }
  10
  11 struct A<T>(T);
  12
  13 impl<T: C> Foo<T> for A<T> {
  14     const BAR: usize = [5, 6, 7][T::BOO]; //~ ERROR evaluation of `<A<()> as Foo<()>>::BAR` failed
  15 }
  16
  17 fn foo<T: C>() -> &'static usize {
  18     &<A<T> as Foo<T>>::BAR //~ constant
  19 }
  20
  21 impl C for () {
  22     const BOO: usize = 42;
  23 }
  24
  25 impl C for u32 {
  26     const BOO: usize = 1;
  27 }
  28
  29 fn main() {
  30     println!("{:x}", foo::<()>() as *const usize as usize);
  31     println!("{:x}", foo::<u32>() as *const usize as usize);
  32     println!("{:x}", foo::<()>());
  33     println!("{:x}", foo::<u32>());
  34 }