{"action":"created","issue":{"url":"https://api.github.com/repos/Microsoft/visualfsharp/issues/1200","repository_url":"https://api.github.com/repos/Microsoft/visualfsharp","labels_url":"https://api.github.com/repos/Microsoft/visualfsharp/issues/1200/labels{/name}","comments_url":"https://api.github.com/repos/Microsoft/visualfsharp/issues/1200/comments","events_url":"https://api.github.com/repos/Microsoft/visualfsharp/issues/1200/events","html_url":"https://github.com/Microsoft/visualfsharp/issues/1200","id":155458379,"number":1200,"title":"Compilation error when implementing interface using object expressions and tuple argument","user":{"login":"JanWosnitza","id":2276629,"avatar_url":"https://avatars.githubusercontent.com/u/2276629?v=3","gravatar_id":"","url":"https://api.github.com/users/JanWosnitza","html_url":"https://github.com/JanWosnitza","followers_url":"https://api.github.com/users/JanWosnitza/followers","following_url":"https://api.github.com/users/JanWosnitza/following{/other_user}","gists_url":"https://api.github.com/users/JanWosnitza/gists{/gist_id}","starred_url":"https://api.github.com/users/JanWosnitza/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/JanWosnitza/subscriptions","organizations_url":"https://api.github.com/users/JanWosnitza/orgs","repos_url":"https://api.github.com/users/JanWosnitza/repos","events_url":"https://api.github.com/users/JanWosnitza/events{/privacy}","received_events_url":"https://api.github.com/users/JanWosnitza/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":3,"created_at":"2016-05-18T09:43:06Z","updated_at":"2016-05-18T10:22:29Z","closed_at":null,"body":"Surprising compilation error when trying to implement an interface using object expressions.\r\n\r\n#### Repro Steps\r\n```\r\ntype IInterface =\r\n    abstract Function : (int32 * int32) -> unit\r\n\r\n{ new IInterface with\r\n    member this.Function (i, j) = ()\r\n}\r\n```\r\n\r\n#### Expected\r\nCompilation without errors like this:\r\n\r\n```\r\ntype IInterface =\r\n    abstract Function : int32 -> unit\r\n\r\n{ new IInterface'with\r\n    member this.Function (i) = ()\r\n}\r\n\r\n```\r\n\r\n#### Actual\r\nThe compilation error is:\r\n> FS0768: The member 'Function' does not accept the correct number of arguments, 1 arguments are expected\r\n\r\n#### Severity\r\n- Confusing for newcomers.\r\n- Cumbersome to remember.\r\n- But easy workaround.\r\n\r\n#### Version\r\n- F# 4.0 (FSharp.Core, 4.4.0.0)\r\n- F# Compiler version 14.0.23413.0\r\n- .NET Runtime, Framwork 4.6\r\n- Windows 10\r\n- Visual Studio Community 2015 version 14.0.2513.00 Update 2\r\n\r\n#### Workaround\r\nSurround the error producing parameter with additional brackets:\r\n```\r\ntype IInterface =\r\n    abstract Function : (int32 * int32) -> unit\r\n\r\n{ new IInterface with\r\n    member this.Function ((i, j)) = ()\r\n}\r\n\r\n```"},"comment":{"url":"https://api.github.com/repos/Microsoft/visualfsharp/issues/comments/219986051","html_url":"https://github.com/Microsoft/visualfsharp/issues/1200#issuecomment-219986051","issue_url":"https://api.github.com/repos/Microsoft/visualfsharp/issues/1200","id":219986051,"user":{"login":"isaacabraham","id":1781813,"avatar_url":"https://avatars.githubusercontent.com/u/1781813?v=3","gravatar_id":"","url":"https://api.github.com/users/isaacabraham","html_url":"https://github.com/isaacabraham","followers_url":"https://api.github.com/users/isaacabraham/followers","following_url":"https://api.github.com/users/isaacabraham/following{/other_user}","gists_url":"https://api.github.com/users/isaacabraham/gists{/gist_id}","starred_url":"https://api.github.com/users/isaacabraham/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/isaacabraham/subscriptions","organizations_url":"https://api.github.com/users/isaacabraham/orgs","repos_url":"https://api.github.com/users/isaacabraham/repos","events_url":"https://api.github.com/users/isaacabraham/events{/privacy}","received_events_url":"https://api.github.com/users/isaacabraham/received_events","type":"User","site_admin":false},"created_at":"2016-05-18T10:22:28Z","updated_at":"2016-05-18T10:22:28Z","body":"@forki My thoughts exactly. If this becomes a fully fledged \"improve error message\" I'll add it to the (growing!) list."}}