{"action":"opened","issue":{"url":"https://api.github.com/repos/rust-lang/rust-by-example/issues/627","labels_url":"https://api.github.com/repos/rust-lang/rust-by-example/issues/627/labels{/name}","comments_url":"https://api.github.com/repos/rust-lang/rust-by-example/issues/627/comments","events_url":"https://api.github.com/repos/rust-lang/rust-by-example/issues/627/events","html_url":"https://github.com/rust-lang/rust-by-example/issues/627","id":99527012,"number":627,"title":"Traits use of bounds includes previous un-described behavior","user":{"login":"chriskrycho","id":2403023,"avatar_url":"https://avatars.githubusercontent.com/u/2403023?v=3","gravatar_id":"","url":"https://api.github.com/users/chriskrycho","html_url":"https://github.com/chriskrycho","followers_url":"https://api.github.com/users/chriskrycho/followers","following_url":"https://api.github.com/users/chriskrycho/following{/other_user}","gists_url":"https://api.github.com/users/chriskrycho/gists{/gist_id}","starred_url":"https://api.github.com/users/chriskrycho/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/chriskrycho/subscriptions","organizations_url":"https://api.github.com/users/chriskrycho/orgs","repos_url":"https://api.github.com/users/chriskrycho/repos","events_url":"https://api.github.com/users/chriskrycho/events{/privacy}","received_events_url":"https://api.github.com/users/chriskrycho/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-08-06T21:18:04Z","updated_at":"2015-08-06T21:18:04Z","closed_at":null,"body":"In [**15.3: Bounds**](http://rustbyexample.com/trait/bounds.html), the example code includes the following:\r\n\r\n```rust\r\nimpl<T: Add<T, Output = T>> Add<Vec2<T>>\r\n        for Vec2<T> {\r\n// ...\r\n}\r\n```\r\n\r\nThe declaration with the type assigned `Output = T` has not been covered previously in the book, and it's neither commented here, nor readily apparent from the context, how it behaves. (I'm off to go look it up in the main docs myself presently!)"}}