{"action":"created","issue":{"url":"https://api.github.com/repos/rust-lang/rust/issues/24125","labels_url":"https://api.github.com/repos/rust-lang/rust/issues/24125/labels{/name}","comments_url":"https://api.github.com/repos/rust-lang/rust/issues/24125/comments","events_url":"https://api.github.com/repos/rust-lang/rust/issues/24125/events","html_url":"https://github.com/rust-lang/rust/issues/24125","id":66694463,"number":24125,"title":"`unstable feature` error needs to specify feature names for better usability.","user":{"login":"nejucomo","id":480497,"avatar_url":"https://avatars.githubusercontent.com/u/480497?v=3","gravatar_id":"","url":"https://api.github.com/users/nejucomo","html_url":"https://github.com/nejucomo","followers_url":"https://api.github.com/users/nejucomo/followers","following_url":"https://api.github.com/users/nejucomo/following{/other_user}","gists_url":"https://api.github.com/users/nejucomo/gists{/gist_id}","starred_url":"https://api.github.com/users/nejucomo/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nejucomo/subscriptions","organizations_url":"https://api.github.com/users/nejucomo/orgs","repos_url":"https://api.github.com/users/nejucomo/repos","events_url":"https://api.github.com/users/nejucomo/events{/privacy}","received_events_url":"https://api.github.com/users/nejucomo/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/rust-lang/rust/labels/A-diagnostics","name":"A-diagnostics","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/P-medium","name":"P-medium","color":"eb6420"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":12,"created_at":"2015-04-06T20:10:41Z","updated_at":"2015-06-17T18:39:34Z","closed_at":null,"body":"**Synopsis:** The `unstable feature` compiler error does not specify the explicit feature, so when many are enabled in a single line, the user cannot tell which subset are unstable.\r\n\r\n**What I did:** Tried to build [rust-peg](https://github.com/kevinmehall/rust-peg) with ``rustc 1.0.0-beta (9854143cb 2015-04-02) (built 2015-04-02)``\r\n\r\n**What I expected:** A specific error message that let's me know which unstable features I must explicitly enable in order to build ``rust-peg``.\r\n\r\n**What happened:** I got the following error ([rust-peg ticket #72](https://github.com/kevinmehall/rust-peg/issues/72)):\r\n\r\n```\r\nsrc/peg_syntax_ext.rs:1:1: 1:107 error: unstable feature\r\nsrc/peg_syntax_ext.rs:1 #![feature(plugin_registrar, quote, box_syntax, core, collections, rustc_private, box_patterns, str_char)]\r\n                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\r\nnote: this feature may not be used in the beta release channel\r\nerror: aborting due to previous error\r\nCould not compile `peg`.\r\n```\r\n\r\nWhich feature(s) are unstable? The error message needs to be more specific, otherwise I need to try each combination in the superset. :-<\r\n\r\n## Meta:\r\n\r\n```\r\n$ rustc --version --verbose\r\nrustc 1.0.0-beta (9854143cb 2015-04-02) (built 2015-04-02)\r\nbinary: rustc\r\ncommit-hash: 9854143cba679834bc4ef932858cd5303f015a0e\r\ncommit-date: 2015-04-02\r\nbuild-date: 2015-04-02\r\nhost: x86_64-unknown-linux-gnu\r\nrelease: 1.0.0-beta\r\n```"},"comment":{"url":"https://api.github.com/repos/rust-lang/rust/issues/comments/112909777","html_url":"https://github.com/rust-lang/rust/issues/24125#issuecomment-112909777","issue_url":"https://api.github.com/repos/rust-lang/rust/issues/24125","id":112909777,"user":{"login":"brson","id":147214,"avatar_url":"https://avatars.githubusercontent.com/u/147214?v=3","gravatar_id":"","url":"https://api.github.com/users/brson","html_url":"https://github.com/brson","followers_url":"https://api.github.com/users/brson/followers","following_url":"https://api.github.com/users/brson/following{/other_user}","gists_url":"https://api.github.com/users/brson/gists{/gist_id}","starred_url":"https://api.github.com/users/brson/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/brson/subscriptions","organizations_url":"https://api.github.com/users/brson/orgs","repos_url":"https://api.github.com/users/brson/repos","events_url":"https://api.github.com/users/brson/events{/privacy}","received_events_url":"https://api.github.com/users/brson/received_events","type":"User","site_admin":false},"created_at":"2015-06-17T18:39:34Z","updated_at":"2015-06-17T18:39:34Z","body":"I've started a patch."}}