warning: attempt to subtract with overflow
  --> $DIR/pub_const_err.rs:15:20
   |
LL | pub const Z: u32 = 0 - 1;
   |                    ^^^^^
   |
   = note: #[warn(const_err)] on by default

warning: this constant cannot be used
  --> $DIR/pub_const_err.rs:15:1
   |
LL | pub const Z: u32 = 0 - 1;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^ attempt to subtract with overflow

warning: attempt to subtract with overflow
  --> $DIR/pub_const_err.rs:19:22
   |
LL | pub type Foo = [i32; 0 - 1];
   |                      ^^^^^

warning: this array length cannot be used
  --> $DIR/pub_const_err.rs:19:22
   |
LL | pub type Foo = [i32; 0 - 1];
   |                      ^^^^^ attempt to subtract with overflow