{"action":"created","issue":{"url":"https://api.github.com/repos/non/cats/issues/541","labels_url":"https://api.github.com/repos/non/cats/issues/541/labels{/name}","comments_url":"https://api.github.com/repos/non/cats/issues/541/comments","events_url":"https://api.github.com/repos/non/cats/issues/541/events","html_url":"https://github.com/non/cats/issues/541","id":108292374,"number":541,"title":"Monad null instance","user":{"login":"gabro","id":691940,"avatar_url":"https://avatars.githubusercontent.com/u/691940?v=3","gravatar_id":"","url":"https://api.github.com/users/gabro","html_url":"https://github.com/gabro","followers_url":"https://api.github.com/users/gabro/followers","following_url":"https://api.github.com/users/gabro/following{/other_user}","gists_url":"https://api.github.com/users/gabro/gists{/gist_id}","starred_url":"https://api.github.com/users/gabro/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/gabro/subscriptions","organizations_url":"https://api.github.com/users/gabro/orgs","repos_url":"https://api.github.com/users/gabro/repos","events_url":"https://api.github.com/users/gabro/events{/privacy}","received_events_url":"https://api.github.com/users/gabro/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-09-25T09:32:00Z","updated_at":"2015-09-25T09:45:56Z","closed_at":null,"body":"```\r\nimport cats._\r\nimport cats.data._\r\nimport cats.std.future._\r\nimport scala.concurrent.ExecutionContext.Implicits.global\r\nimport scala.concurrent.Future\r\n\r\ntype Response[A] = OptionT[Future, A]\r\n\r\nimplicit val monadInstance: Monad[Response] = Monad[({ type x[A] = OptionT[Future, A] })#x] // null\r\n```\r\n\r\nI would expect this not to compile, but it returns `null` instead.\r\n\r\nAny ideas?"},"comment":{"url":"https://api.github.com/repos/non/cats/issues/comments/143173917","html_url":"https://github.com/non/cats/issues/541#issuecomment-143173917","issue_url":"https://api.github.com/repos/non/cats/issues/541","id":143173917,"user":{"login":"gabro","id":691940,"avatar_url":"https://avatars.githubusercontent.com/u/691940?v=3","gravatar_id":"","url":"https://api.github.com/users/gabro","html_url":"https://github.com/gabro","followers_url":"https://api.github.com/users/gabro/followers","following_url":"https://api.github.com/users/gabro/following{/other_user}","gists_url":"https://api.github.com/users/gabro/gists{/gist_id}","starred_url":"https://api.github.com/users/gabro/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/gabro/subscriptions","organizations_url":"https://api.github.com/users/gabro/orgs","repos_url":"https://api.github.com/users/gabro/repos","events_url":"https://api.github.com/users/gabro/events{/privacy}","received_events_url":"https://api.github.com/users/gabro/received_events","type":"User","site_admin":false},"created_at":"2015-09-25T09:45:56Z","updated_at":"2015-09-25T09:45:56Z","body":"Ok, weird, dropping the `Monad[Reponse]` return type from `monadInstance` makes it work.\r\n\r\nI would definitely expect a compile-time error here."}}