error: Suspicious use of binary operator in `Add` impl
  --> $DIR/suspicious_arithmetic_impl.rs:14:20
   |
14 |         Foo(self.0 - other.0)
   |                    ^
   |
   = note: `-D suspicious-arithmetic-impl` implied by `-D warnings`

error: Suspicious use of binary operator in `AddAssign` impl
  --> $DIR/suspicious_arithmetic_impl.rs:20:23
   |
20 |         *self = *self - other;
   |                       ^
   |
   = note: #[deny(suspicious_op_assign_impl)] on by default

error: aborting due to 2 previous errors