{"action":"created","issue":{"url":"https://api.github.com/repos/rust-lang/rust/issues/21687","labels_url":"https://api.github.com/repos/rust-lang/rust/issues/21687/labels{/name}","comments_url":"https://api.github.com/repos/rust-lang/rust/issues/21687/comments","events_url":"https://api.github.com/repos/rust-lang/rust/issues/21687/events","html_url":"https://github.com/rust-lang/rust/issues/21687","id":55588112,"number":21687,"title":"Impl reachability rules bug?","user":{"login":"vadimcn","id":3203809,"avatar_url":"https://avatars.githubusercontent.com/u/3203809?v=3","gravatar_id":"","url":"https://api.github.com/users/vadimcn","html_url":"https://github.com/vadimcn","followers_url":"https://api.github.com/users/vadimcn/followers","following_url":"https://api.github.com/users/vadimcn/following{/other_user}","gists_url":"https://api.github.com/users/vadimcn/gists{/gist_id}","starred_url":"https://api.github.com/users/vadimcn/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/vadimcn/subscriptions","organizations_url":"https://api.github.com/users/vadimcn/orgs","repos_url":"https://api.github.com/users/vadimcn/repos","events_url":"https://api.github.com/users/vadimcn/events{/privacy}","received_events_url":"https://api.github.com/users/vadimcn/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":3,"created_at":"2015-01-27T08:15:24Z","updated_at":"2015-01-27T16:00:12Z","closed_at":"2015-01-27T16:00:12Z","body":"```rust\r\nuse std::default::Default;\r\n\r\ntrait AAA {}\r\ntrait BBB<T> {}\r\nstruct SSS<T>(T);\r\n\r\nimpl<T,U> AAA for SSS<T> where T:BBB<U>, U:Default {}\r\n```\r\n```\r\n<anon>:7:8: 7:9 error: the type parameter `U` is not constrained by the impl trait, self type, or predicates [E0207]\r\n<anon>:7 impl<T,U> AAA for SSS<T> where T:BBB<U>, U:Default {}\r\n                ^\r\n<anon>:7:8: 7:9 help: you can temporarily opt out of this rule by placing the `#[old_impl_check]` attribute on the impl\r\n<anon>:7 impl<T,U> AAA for SSS<T> where T:BBB<U>, U:Default {}\r\n                ^\r\n```\r\nI don't understand why I get the error, since U *is* constrained by the where predicate."},"comment":{"url":"https://api.github.com/repos/rust-lang/rust/issues/comments/71672367","html_url":"https://github.com/rust-lang/rust/issues/21687#issuecomment-71672367","issue_url":"https://api.github.com/repos/rust-lang/rust/issues/21687","id":71672367,"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":"2015-01-27T16:00:12Z","updated_at":"2015-01-27T16:00:12Z","body":"Closing because this test is working as expected."}}