warning: attempt to subtract with overflow
  --> $DIR/conditional_array_execution.rs:15:19
   |
LL | const FOO: u32 = [X - Y, Y - X][(X < Y) as usize];
   |                   ^^^^^
   |
   = note: #[warn(const_err)] on by default

warning: constant evaluation error
  --> $DIR/conditional_array_execution.rs:19:20
   |
LL |     println!("{}", FOO);
   |                    ^^^ referenced constant has errors