{"action":"created","issue":{"url":"https://api.github.com/repos/rust-lang/rust/issues/20783","labels_url":"https://api.github.com/repos/rust-lang/rust/issues/20783/labels{/name}","comments_url":"https://api.github.com/repos/rust-lang/rust/issues/20783/comments","events_url":"https://api.github.com/repos/rust-lang/rust/issues/20783/events","html_url":"https://github.com/rust-lang/rust/issues/20783","id":53824156,"number":20783,"title":"Custom errors for well-known traits","user":{"login":"nikomatsakis","id":155238,"avatar_url":"https://avatars.githubusercontent.com/u/155238?v=3","gravatar_id":"","url":"https://api.github.com/users/nikomatsakis","html_url":"https://github.com/nikomatsakis","followers_url":"https://api.github.com/users/nikomatsakis/followers","following_url":"https://api.github.com/users/nikomatsakis/following{/other_user}","gists_url":"https://api.github.com/users/nikomatsakis/gists{/gist_id}","starred_url":"https://api.github.com/users/nikomatsakis/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nikomatsakis/subscriptions","organizations_url":"https://api.github.com/users/nikomatsakis/orgs","repos_url":"https://api.github.com/users/nikomatsakis/repos","events_url":"https://api.github.com/users/nikomatsakis/events{/privacy}","received_events_url":"https://api.github.com/users/nikomatsakis/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/rust-lang/rust/labels/E-mentor","name":"E-mentor","color":"02E10C"},{"url":"https://api.github.com/repos/rust-lang/rust/labels/I-nominated","name":"I-nominated","color":"e10c02"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":9,"created_at":"2015-01-09T01:35:17Z","updated_at":"2015-01-10T12:07:56Z","closed_at":null,"body":"Consider these comments by the one and only @steveklabnik:\r\n\r\n```\r\n[17:20:10] <steveklabnik> ugh\r\n[17:20:19] <steveklabnik> so close to getting this to compile\r\n[17:20:21] <steveklabnik> and i am rewarded with\r\n[17:20:27] <steveklabnik>  error: the trait `core::iter::FromIterator<core::result::Result<(collections::vec::Vec<usize>, collections::string::String), std::sync::mpsc::RecvError>>` is not implemented\r\n                          for the type `collections::vec::Vec<(collections::vec::Vec<usize>, collections::string::String)>`\r\n[17:20:31] <steveklabnik> O_O\r\n[17:21:01] <steveklabnik> that one is easy i guess\r\n[17:21:04] <steveklabnik> just a scary message\r\n```\r\n\r\nwouldn't it be nicer if the compiler saw that error involved `FromIterator` and printed something like \"the type you are iterating over doesn't match the expected type of the collection you are creating\"?\r\n\r\nNominating for 1.0 (not beta), because this could be a big usability benefit. I'm sure there are other \"well-known\" traits we could do this for."},"comment":{"url":"https://api.github.com/repos/rust-lang/rust/issues/comments/69453678","html_url":"https://github.com/rust-lang/rust/issues/20783#issuecomment-69453678","issue_url":"https://api.github.com/repos/rust-lang/rust/issues/20783","id":69453678,"user":{"login":"nikomatsakis","id":155238,"avatar_url":"https://avatars.githubusercontent.com/u/155238?v=3","gravatar_id":"","url":"https://api.github.com/users/nikomatsakis","html_url":"https://github.com/nikomatsakis","followers_url":"https://api.github.com/users/nikomatsakis/followers","following_url":"https://api.github.com/users/nikomatsakis/following{/other_user}","gists_url":"https://api.github.com/users/nikomatsakis/gists{/gist_id}","starred_url":"https://api.github.com/users/nikomatsakis/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nikomatsakis/subscriptions","organizations_url":"https://api.github.com/users/nikomatsakis/orgs","repos_url":"https://api.github.com/users/nikomatsakis/repos","events_url":"https://api.github.com/users/nikomatsakis/events{/privacy}","received_events_url":"https://api.github.com/users/nikomatsakis/received_events","type":"User","site_admin":false},"created_at":"2015-01-10T12:07:56Z","updated_at":"2015-01-10T12:07:56Z","body":"@P1start makes sense. In any case, seems like we should start with *something* and grow as we go. This wouldn't a stable attribute anyway (at least not for some time)."}}