220 13367 article Path: news.gmane.org!not-for-mail From: Ville Voutilainen Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Tighten rules for virtual override keyword combination Date: Tue, 30 Sep 2014 12:53:42 +0300 Lines: 36 Approved: news@gmane.org Message-ID: References: <19267205-7e26-4c12-b9b4-f26ab2f99eb7@isocpp.org> <803262EF-88B4-40B0-AC9B-7C7356CDE56A@gmail.com> <54274B57.6040007@gmail.com> <8DC1AED8-83B6-453A-A93A-EAB6AF942968@gmail.com> <39638C85-5546-444B-A7AA-F873947777B4@gmail.com> <22C84181-5761-4744-AC90-6E252B5CB1E4@gmail.com> <9367C570-6D36-4E88-BFD3-85F5A632DEDE@gmail.com> <8C19FE11-C9BF-446D-8CFF-FEB52FEA546C@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1412070832 29360 80.91.229.3 (30 Sep 2014 09:53:52 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 30 Sep 2014 09:53:52 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBC5JHI7A7ALRBJ73VGQQKGQEQOMKTPA@isocpp.org Tue Sep 30 11:53:45 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vc0-f199.google.com ([209.85.220.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XYu7s-0003YL-WE for gclcip-std-proposals@m.gmane.org; Tue, 30 Sep 2014 11:53:45 +0200 Original-Received: by mail-vc0-f199.google.com with SMTP id ij19sf1003247vcb.10 for ; Tue, 30 Sep 2014 02:53:43 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type; bh=qs8VfHaNXnHfgZRtg1E2cEVirmkQBXVvuBeWEExipGE=; b=A0tNK4XJplLkHAg2R1p2uxiieZm+y7CVYXchZzuvpaVf0MfL0OkvuYKbhVko2a08TV pY765zk1AcXufL8Uqg/wEs5d8Ke6MuiR2t2U2PunfXBB3iTg0T83e1+YD4XAFdVn9cmt k9lnNDay+dpc5V9LIHwKY4boKYh9nKhig2GYXOJkltqU5ssrIP5CvFMXblpgaFwvwAX0 jO7Cx6DRtK8qWk+CABuXefckjsPkIpfO+PN3fY+f/Wc4BquMaPG1r58TonbZKXwr+Ocp lUVcGXe2blBjFdq8oMyqK09Ofw4sHFK8JqeuqTnKh8uN2a4OohPs4L6Lav3dspUSi7bI f+UA== X-Gm-Message-State: ALoCoQmhu6uJxZ4PkszwfYf1NINwb9An9+CdVFd3DdgBLaQ1TWjI727ljfbHZN4vDBCLUU+WzH0n X-Received: by 10.52.167.129 with SMTP id zo1mr38800686vdb.2.1412070823592; Tue, 30 Sep 2014 02:53:43 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.50.66.240 with SMTP id i16ls99489igt.41.gmail; Tue, 30 Sep 2014 02:53:42 -0700 (PDT) X-Received: by 10.42.70.11 with SMTP id d11mr9350519icj.92.1412070822915; Tue, 30 Sep 2014 02:53:42 -0700 (PDT) Original-Received: from mail-ig0-x235.google.com (mail-ig0-x235.google.com [2607:f8b0:4001:c05::235]) by mx.google.com with ESMTPS id j10si14818791igt.4.2014.09.30.02.53.42 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 30 Sep 2014 02:53:42 -0700 (PDT) Received-SPF: pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:4001:c05::235 as permitted sender) client-ip=2607:f8b0:4001:c05::235; Original-Received: by mail-ig0-f181.google.com with SMTP id r10so363214igi.14 for ; Tue, 30 Sep 2014 02:53:42 -0700 (PDT) X-Received: by 10.42.237.197 with SMTP id kp5mr3152438icb.49.1412070822682; Tue, 30 Sep 2014 02:53:42 -0700 (PDT) Original-Received: by 10.42.44.8 with HTTP; Tue, 30 Sep 2014 02:53:42 -0700 (PDT) In-Reply-To: X-Original-Sender: ville.voutilainen@gmail.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of ville.voutilainen@gmail.com designates 2607:f8b0:4001:c05::235 as permitted sender) smtp.mail=ville.voutilainen@gmail.com; dkim=pass header.i=@gmail.com; dmarc=pass (p=NONE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:13367 Archived-At: On 30 September 2014 09:53, Ville Voutilainen wrote: >>> And whatever the alternative would've supposed to be in some hypothetical >>> world, those alternatives were not suggested strongly enough, or perhaps at all, >>> so we didn't choose them. Changing such a decision will be hard. >> Yes, the ship has sailed. I find it hard to believe that "final implies override" simply never occurred to the designers though. > > I have very vague recollection of such considerations, if any; perhaps > it did occur, sure, > but we certainly decided to keep final uncoupled from override without much ado. And there's another case where we don't even want final to imply or require override: template struct X : T { virtual void f() final; }; If T has a virtual f(), this would work fine. If T doesn't, we have an ill-formed class. So, in order to be able to say that f() is final onward from X regardless of whether it's virtual in T, we need the current semantics. If you want to instead say that f() is final onward from X and it must be virtual in T, add override into the mix, done. -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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