message: Fix promotion of negative isize
diff: @@ -340,7 +340,7 @@ macro_rules! promote_signed_scalars {
  macro_rules! promote_signed_scalars_assign {
  (impl $imp:ident for $res:ty, $method:ident) => {
  promote_scalars_assign!(impl $imp<i32> for $res, $method, i8, i16);
  - promote_scalars_assign!(impl $imp<UsizePromotion> for $res, $method, isize);
  + promote_scalars_assign!(impl $imp<IsizePromotion> for $res, $method, isize);
  }
  }
  