{"action":"created","issue":{"url":"https://api.github.com/repos/rust-lang/rust/issues/31062","repository_url":"https://api.github.com/repos/rust-lang/rust","labels_url":"https://api.github.com/repos/rust-lang/rust/issues/31062/labels{/name}","comments_url":"https://api.github.com/repos/rust-lang/rust/issues/31062/comments","events_url":"https://api.github.com/repos/rust-lang/rust/issues/31062/events","html_url":"https://github.com/rust-lang/rust/issues/31062","id":127778566,"number":31062,"title":"provide on_unimplemented hint for ops::Index","user":{"login":"durka","id":47007,"avatar_url":"https://avatars.githubusercontent.com/u/47007?v=3","gravatar_id":"","url":"https://api.github.com/users/durka","html_url":"https://github.com/durka","followers_url":"https://api.github.com/users/durka/followers","following_url":"https://api.github.com/users/durka/following{/other_user}","gists_url":"https://api.github.com/users/durka/gists{/gist_id}","starred_url":"https://api.github.com/users/durka/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/durka/subscriptions","organizations_url":"https://api.github.com/users/durka/orgs","repos_url":"https://api.github.com/users/durka/repos","events_url":"https://api.github.com/users/durka/events{/privacy}","received_events_url":"https://api.github.com/users/durka/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/rust-lang/rust/labels/A-libs","name":"A-libs","color":"d7e102"},{"url":"https://api.github.com/repos/rust-lang/rust/labels/E-easy","name":"E-easy","color":"02e10c"},{"url":"https://api.github.com/repos/rust-lang/rust/labels/I-enhancement","name":"I-enhancement","color":"e10c02"},{"url":"https://api.github.com/repos/rust-lang/rust/labels/I-papercut","name":"I-papercut","color":"e10c02"}],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":6,"created_at":"2016-01-20T20:37:40Z","updated_at":"2016-05-17T07:25:32Z","closed_at":"2016-05-12T02:59:11Z","body":"As discussed on IRC. cc @steveklabnik \r\n\r\nIf you do `slice[2i32]` you get an error that tells you what is wrong (`Index<i32>` is not implemented for `[T]`) but not how to fix it (slices are indexed by usize). A quick fix would be to use `#[rustc_on_unimplemented]`; it would look [like this](http://is.gd/Wei0AV).\r\n\r\nIf you are indexing something that isn't `[T]` then the message would be a false positive."},"comment":{"url":"https://api.github.com/repos/rust-lang/rust/issues/comments/219639609","html_url":"https://github.com/rust-lang/rust/issues/31062#issuecomment-219639609","issue_url":"https://api.github.com/repos/rust-lang/rust/issues/31062","id":219639609,"user":{"login":"pnkfelix","id":173127,"avatar_url":"https://avatars.githubusercontent.com/u/173127?v=3","gravatar_id":"","url":"https://api.github.com/users/pnkfelix","html_url":"https://github.com/pnkfelix","followers_url":"https://api.github.com/users/pnkfelix/followers","following_url":"https://api.github.com/users/pnkfelix/following{/other_user}","gists_url":"https://api.github.com/users/pnkfelix/gists{/gist_id}","starred_url":"https://api.github.com/users/pnkfelix/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/pnkfelix/subscriptions","organizations_url":"https://api.github.com/users/pnkfelix/orgs","repos_url":"https://api.github.com/users/pnkfelix/repos","events_url":"https://api.github.com/users/pnkfelix/events{/privacy}","received_events_url":"https://api.github.com/users/pnkfelix/received_events","type":"User","site_admin":false},"created_at":"2016-05-17T07:25:32Z","updated_at":"2016-05-17T07:25:32Z","body":"@arielb1 I inferred that something regressed from the fact that you removed one of unit tests in #33491, but I guess I am not clear on how much of a regression occurred."}}