From a5a5c1074e67a5c12157eb88b7a4f055c8938108 Mon Sep 17 00:00:00 2001
From: "Panashe M. Fundira" <fundirap@gmail.com>
Date: Sun, 21 Aug 2016 23:09:18 -0400
Subject: [PATCH 1/2] Add reference to `Self` in traits chapter (book)
---
src/doc/book/traits.md | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/src/doc/book/traits.md b/src/doc/book/traits.md
index e685cb129b939..164a851edeff4 100644
--- a/src/doc/book/traits.md
+++ b/src/doc/book/traits.md
@@ -47,6 +47,28 @@ As you can see, the `trait` block looks very similar to the `impl` block,
but we don’t define a body, only a type signature. When we `impl` a trait,
we use `impl Trait for Item`, rather than only `impl Item`.
+`Self` may be used in a type annotation to refer to an instance of the type
+implementing this trait passed as a parameter. `Self`, `&Self` or `&mut Self`
+may be used depending on the level of ownership required.
+
+```rust
+trait HasArea {
+ fn area(&self) -> f64;
+
+ fn is_larger(&self, &Self) -> bool;
+}
+
+impl HasArea for Circle {
+ fn area(&self) -> f64 {
+ std::f64::consts::PI * (self.radius * self.radius)
+ }
+
+ fn is_larger(&self, other: &Self) -> bool {
+ self.area() > other.area()
+ }
+}
+```
+
## Trait bounds on generic functions
Traits are useful because they allow a type to make certain promises about its
From 3da5f9327a3a54a280a299fd38ff8376d3d5d419 Mon Sep 17 00:00:00 2001
From: "Panashe M. Fundira" <fundirap@gmail.com>
Date: Mon, 22 Aug 2016 12:10:02 -0400
Subject: [PATCH 2/2] Correct failing book test
---
src/doc/book/traits.md | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/src/doc/book/traits.md b/src/doc/book/traits.md
index 164a851edeff4..9cbb514e28065 100644
--- a/src/doc/book/traits.md
+++ b/src/doc/book/traits.md
@@ -52,6 +52,12 @@ implementing this trait passed as a parameter. `Self`, `&Self` or `&mut Self`
may be used depending on the level of ownership required.
```rust
+struct Circle {
+ x: f64,
+ y: f64,
+ radius: f64,
+}
+
trait HasArea {
fn area(&self) -> f64;