{"action":"created","issue":{"url":"https://api.github.com/repos/manastech/crystal/issues/989","labels_url":"https://api.github.com/repos/manastech/crystal/issues/989/labels{/name}","comments_url":"https://api.github.com/repos/manastech/crystal/issues/989/comments","events_url":"https://api.github.com/repos/manastech/crystal/issues/989/events","html_url":"https://github.com/manastech/crystal/issues/989","id":95467227,"number":989,"title":"is_a? should warn/error out if it could never possibly return true","user":{"login":"kirbyfan64","id":1690697,"avatar_url":"https://avatars.githubusercontent.com/u/1690697?v=3","gravatar_id":"","url":"https://api.github.com/users/kirbyfan64","html_url":"https://github.com/kirbyfan64","followers_url":"https://api.github.com/users/kirbyfan64/followers","following_url":"https://api.github.com/users/kirbyfan64/following{/other_user}","gists_url":"https://api.github.com/users/kirbyfan64/gists{/gist_id}","starred_url":"https://api.github.com/users/kirbyfan64/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/kirbyfan64/subscriptions","organizations_url":"https://api.github.com/users/kirbyfan64/orgs","repos_url":"https://api.github.com/users/kirbyfan64/repos","events_url":"https://api.github.com/users/kirbyfan64/events{/privacy}","received_events_url":"https://api.github.com/users/kirbyfan64/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":2,"created_at":"2015-07-16T16:01:56Z","updated_at":"2015-07-16T16:25:40Z","closed_at":null,"body":"This compiles but makes no sense:\r\n\r\n```crystal\r\nputs 5.is_a? String\r\n```\r\n\r\nThis has also bitten me as a bug before. IMO, it should be an error. It's usually a side effect of a code change and is pretty much never intended.\r\n"},"comment":{"url":"https://api.github.com/repos/manastech/crystal/issues/comments/122010580","html_url":"https://github.com/manastech/crystal/issues/989#issuecomment-122010580","issue_url":"https://api.github.com/repos/manastech/crystal/issues/989","id":122010580,"user":{"login":"asterite","id":209371,"avatar_url":"https://avatars.githubusercontent.com/u/209371?v=3","gravatar_id":"","url":"https://api.github.com/users/asterite","html_url":"https://github.com/asterite","followers_url":"https://api.github.com/users/asterite/followers","following_url":"https://api.github.com/users/asterite/following{/other_user}","gists_url":"https://api.github.com/users/asterite/gists{/gist_id}","starred_url":"https://api.github.com/users/asterite/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/asterite/subscriptions","organizations_url":"https://api.github.com/users/asterite/orgs","repos_url":"https://api.github.com/users/asterite/repos","events_url":"https://api.github.com/users/asterite/events{/privacy}","received_events_url":"https://api.github.com/users/asterite/received_events","type":"User","site_admin":false},"created_at":"2015-07-16T16:25:40Z","updated_at":"2015-07-16T16:25:40Z","body":"```\r\n- Is 5 a String?\r\n- No\r\n```\r\n\r\nI don't see why you think this question makes no sense.\r\n\r\nOn the other hand, `5 as String` does give a compile error.\r\n\r\nCan you show some code that is bug prone due to this behaviour?"}}