Replace Add with AddAssign to get rid of another clone.

Similar performance improvements observed in the benchmark:

    change: [-11.816% -11.802% -11.789%] (p = 0.00 < 0.05)
    Performance has improved.

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/lib.rs b/src/lib.rs
index eecdcaf..fbc29e4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,6 @@
 use num::{One, Zero};
 use std::mem;
-use std::ops::Add;
+use std::ops::AddAssign;
 
 #[derive(Debug)]
 pub struct Fib<T> {
@@ -17,13 +17,13 @@ impl<T: Zero + One> Fib<T> {
     }
 }
 
-impl<T: Clone + Add<Output = T>> Iterator for Fib<T> {
+impl<T: Clone + AddAssign> Iterator for Fib<T> {
     type Item = T;
 
     fn next(&mut self) -> Option<Self::Item> {
         let res = self.a.clone();
         mem::swap(&mut self.a, &mut self.b);
-        self.b = self.b.clone() + self.a.clone();
+        self.b += self.a.clone();
 
         Some(res)
     }