From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTP id 75FA3384A4B5 for ; Mon, 19 Aug 2024 21:36:16 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 75FA3384A4B5 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 75FA3384A4B5 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1724103378; cv=none; b=blsmCbyGfJP2+ckxOWNm81N0q8p2YVgX4GWwiotHHO73dtdYbM6s2dVt3QO6f/ECuwh0KE7tZAFRmUdT4wMb1ECJaRY8tqUIxC/0qGT1CppOmMCGmXEM2M7AGtzK8R20+32W8QMrwVPn2iRpymtDvIlvtfsP1dJ07s1CX/+8ebM= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1724103378; c=relaxed/simple; bh=XnfzH5IHyPHUonWlwBcsvVIgKgdC3RlCChp9ONFVS24=; h=DKIM-Signature:MIME-Version:From:Date:Message-ID:Subject:To; b=vbZbAqpAlei62UtJ0buU5JSpzTl3DxCwHIEvTN0QvABbkGYrdVK3knVpArIQjyBs48szwG7B/bBzkAllRXxpx3JSq+YBnz+dkSJQfx1ojY8fxhjB89se+1kfTmO87cL+ld8eHVphmRtCt3vjzpXJW87yyHsCugNbL4N2IjU2+YY= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1724103376; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aVWHXI47HKzTt/94jqe+WgfKoOZsiotu0ZFjtV1TSY8=; b=PtncBHDDEoIrNWacdCV8fbNJvc7iepqC4U+yQ66nFXoF16EZ76U1IFxndZO3Rq+T9vRjl/ eXENDduunsJcpd0V5p7mGPF+nXh/xLN1doyL0MUay19bb4H7Y/8+pDIplTxuzeQPO0XOWq 9xORWkWKkQXhNhUHtdtJgRDNQSRImYo= Received: from mail-yw1-f199.google.com (mail-yw1-f199.google.com [209.85.128.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-171-VuUXBXJoMo64supVKHAfIA-1; Mon, 19 Aug 2024 17:36:14 -0400 X-MC-Unique: VuUXBXJoMo64supVKHAfIA-1 Received: by mail-yw1-f199.google.com with SMTP id 00721157ae682-6b8d96aa5ebso32749427b3.1 for ; Mon, 19 Aug 2024 14:36:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724103373; x=1724708173; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=aVWHXI47HKzTt/94jqe+WgfKoOZsiotu0ZFjtV1TSY8=; b=wfszh1DJ/fFruw5FaGrZeBIezzdNut5in9xTOBKbwdX1zeDs6G3DcpM6cKIMBr6SlK BSHIdiaypn2sIxxZU6cKQhVN0BxUXn84Th9iFoJECAzEyJWZXi3i6Hi8OsjiPEATPhA3 +sgK72fpDTxVNYz8TVzSHd6zbAFoRfsGkn6A5/X1o3cYgKDNh+MvrDyNEjgQuuxjvuSs jOXTRl7EPv7HNv1ok5ZwN+Wag6d5ppBKYN+Ht4DJFV5ac8pSzgSdpa5LjSOrk9gi7Xbs zazoKo86nDK9NeOFF2DE7aQ3c+h8NmI1I3gRHB61vjUawakoNzdoO2D9dELwvOnJltUp xP/g== X-Forwarded-Encrypted: i=1; AJvYcCUtcCa9BtiNT42C/xB2+REyuvrkWA+dMy18MTiGu+0bA6BxEWeGJQqHkWCoFLFMHGd5nUl16WvPRats1A==@gcc.gnu.org X-Gm-Message-State: AOJu0YwhCd6SwODdfrrMKl+IptOFnS9J3y/SVBQKr9MylNB19V4cLVC2 X5yfS+o0eXyvKZPR1RjN2p2aXealnUAhjtpD+XdIQUrubIIKyqOLXF5yrqQyPjOX9hDZY510k/3 heQYGvg/XkNxEBjkkGrP+n5wdYaPrtbr7T4o9mdjhFcs0CoJjD51UXUl1Vo6fx/oTcQhbfmbXe7 l2fZuc8W5Ws4zN7czyvkspxGAUWjBbn0jeuADevA== X-Received: by 2002:a05:690c:7010:b0:6ab:e840:7f4d with SMTP id 00721157ae682-6b1bdb1ed23mr134586247b3.46.1724103373477; Mon, 19 Aug 2024 14:36:13 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHPduUC1aw6zwLbxAAN3lwujTG702tJEyB5cx1Oq9PhkM8/qTUV6PgdL+a2d4wZJyGSWlAhANrsvGbzTTuR1Dw= X-Received: by 2002:a05:690c:7010:b0:6ab:e840:7f4d with SMTP id 00721157ae682-6b1bdb1ed23mr134586157b3.46.1724103373176; Mon, 19 Aug 2024 14:36:13 -0700 (PDT) MIME-Version: 1.0 References: <1892d73a-c210-358c-fe40-c1bafc17fd13@pfeifer.com> In-Reply-To: From: Jonathan Wakely Date: Mon, 19 Aug 2024 22:35:57 +0100 Message-ID: Subject: Re: [wwwdocs] porting_to: Two-stage overload resolution for implicit move removed To: Gerald Pfeifer Cc: Marek Polacek , gcc-patches@gcc.gnu.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,KAM_SHORT,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Mon, 19 Aug 2024 at 22:34, Jonathan Wakely wrote: > > On Mon, 19 Aug 2024 at 21:51, Gerald Pfeifer wrote: > > > > On Wed, 12 Oct 2022, Marek Polacek via Gcc-patches wrote: > > > +

> > > +The two overload resolutions approach was complicated and quirky, so users > > > +should transition to the newer model. This change means that code that > > > +previously didn't compile in C++17 will now compile, for example:

> > > > I looked at this recently and am wondering whether there is a word > > missing: "two overload" -> "two-stage overload"? > > > > If so, the patch below addresses that > > > > On the way, I changed "[code] will now compile" to "[code] may now > > compile", since not every code that failed to compile before will now > > compile (e.g., syntactically incorrect code). > > > > What do you think? > > No, it should either be "two-stage overload resolution" or leave it > unchanged. But "two-stage overload resolutions" (plural) is wrong. And if I had to choose, I think the original text was better. It wasn't two stages, it really was doing overload resolution twice. So there were two overload resolutions. > > > > > > Gerald > > > > > > diff --git a/htdocs/gcc-13/porting_to.html b/htdocs/gcc-13/porting_to.html > > index c727d66f..e595e120 100644 > > --- a/htdocs/gcc-13/porting_to.html > > +++ b/htdocs/gcc-13/porting_to.html > > @@ -82,9 +82,10 @@ not in C++17). Then C++23 P2266 > > removed the fallback overload resolution, and changed the implicit move > > rules once again.

> > > > -

The two overload resolutions approach was complicated and quirky, so users > > -should transition to the newer model. This change means that code that > > -previously didn't compile in C++17 will now compile, for example:

> > +

The two-stage overload resolutions approach was complicated and > > +quirky, so users should transition to the newer model. This change > > +means that code that previously didn't compile in C++17 may now > > +compile, for example:

> > > >

> >     struct S1 { S1(S1 &&); };
> >