message: rust-1.15: avoid Self in constraint
diff: @@ -319,7 +319,7 @@ macro_rules! impl_sum_iter_type {
  ($res:ty) => {
  impl<T> Sum<T> for $res
  where
  - $res: Add<T, Output=Self>
  + $res: Add<T, Output=$res>
  {
  fn sum<I>(iter: I) -> Self
  where
  @@ -335,7 +335,7 @@ macro_rules! impl_product_iter_type {
  ($res:ty) => {
  impl<T> Product<T> for $res
  where
  - $res: Mul<T, Output=Self>
  + $res: Mul<T, Output=$res>
  {
  fn product<I>(iter: I) -> Self
  where
  