warning: constant evaluation error: attempt to subtract with overflow. This will become a HARD ERROR in the future
  --> $DIR/issue-43197.rs:18:20
   |
18 |     const X: u32 = 0-1;
   |                    ^^^
   |
   = note: #[warn(const_err)] on by default

warning: constant evaluation error: attempt to subtract with overflow. This will become a HARD ERROR in the future
  --> $DIR/issue-43197.rs:19:20
   |
19 |     const Y: u32 = foo(0-1);
   |                    ^^^^^^^^

error[E0080]: constant evaluation error
  --> $DIR/issue-43197.rs:18:20
   |
18 |     const X: u32 = 0-1;
   |                    ^^^ attempt to subtract with overflow

error[E0080]: constant evaluation error
  --> $DIR/issue-43197.rs:19:24
   |
19 |     const Y: u32 = foo(0-1);
   |                        ^^^ attempt to subtract with overflow

error: aborting due to 2 previous errors