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[65.55.90.234]) by mx.google.com with ESMTPS id u29si15322497pgn.418.2017.03.14.11.03.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 14 Mar 2017 11:03:05 -0700 (PDT) Received-SPF: pass (google.com: domain of walter.heisenbug@outlook.com designates 65.55.90.234 as permitted sender) client-ip=65.55.90.234; Original-Received: from NAM04-BN3-obe.outbound.protection.outlook.com ([65.55.90.201]) by SNT004-OMC4S31.hotmail.com over TLS secured channel with Microsoft SMTPSVC(7.5.7601.23008); Tue, 14 Mar 2017 11:03:04 -0700 Original-Received: from BN3NAM04FT039.eop-NAM04.prod.protection.outlook.com (10.152.92.52) by BN3NAM04HT141.eop-NAM04.prod.protection.outlook.com (10.152.92.188) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.961.10; Tue, 14 Mar 2017 18:03:03 +0000 Original-Received: from DM5PR2201MB1514.namprd22.prod.outlook.com (10.152.92.53) by BN3NAM04FT039.mail.protection.outlook.com (10.152.93.3) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.961.10 via Frontend Transport; Tue, 14 Mar 2017 18:03:03 +0000 Original-Received: from DM5PR2201MB1514.namprd22.prod.outlook.com ([10.174.187.17]) by DM5PR2201MB1514.namprd22.prod.outlook.com ([10.174.187.17]) with mapi id 15.01.0961.021; Tue, 14 Mar 2017 18:03:03 +0000 Thread-Topic: Allow to access member typedefs of a type from a reference type that's referring to that type Thread-Index: AQHSnOvrv0nJLu2EjkSAUhfJAEmlMA== Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-incomingtopheadermarker: OriginalChecksum:535E67B2D45931315D9CC823B1E66BB6958F17AF7AD25AB2F88CA8B870557D0D;UpperCasedChecksum:259B62F8FD99CFA69D3ABFC794E5E950683907F191E0CD0A91DE3EC6EB760F25;SizeAsReceived:7984;Count:39 x-tmn: [2MkkXJVcEoxU+dOg9edRr8SR22E7NUgr] x-microsoft-exchange-diagnostics: 1;BN3NAM04HT141;5:65IGxfUsWM1TRJIHFdlzjfF098jRQOkt/CMBD6GyalNbimka3Tvmgs5P2fwgi5iiRkyyNukoaRXicyv8Eq8oJpmtuoNfyfAihekab31Z0++WVrZaVYcDsbcw2R1m1NdxKOmVI6CdiyvPfsXb2Spqag==;24:N9d218Y402u+OtNKisJ45BiE6+Vpr4A1aRTcQFvLx6dh6y6EffeNGBLSuWfGbhVkox6WknqUwIOjLyPHXkaoEFBkZNjiJb0U3WR0JLrkZCg=;7:QMVFAn75z1Y9av2tTPZnxpIiIJJjhJcLXi25+O1NabSq5mf94mNOT3Qfot3znzAbiuxPwOTZtu/hvDXwUt6qLS/Opsz1fXiXkVrwCQCHv9EX6wM04aF7Vco2ZN+MVHX/UIVCGxSPHrcszZ89lv9RVpvijlrQxA7CA3ozicHvs9Huaeaia+qeabgkYfiG4Q7w5geGpx2snlDZBhE0u81iwkLzxms7Zl9Dsc214ptgL1YqJXTxeBgTa9dxfYAlhRG781XXXTeYfQP5Zy1DwK3LlcoLgIM3xmtkpyagL97E/6Aebms2uan3hMGES6r720I7 x-incomingheadercount: 39 x-eopattributedmessage: 0 x-forefront-antispam-report: EFV:NLI;SFV:NSPM;SFS:(10019020)(98900017);DIR:OUT;SFP:1102;SCL:1;SRVR:BN3NAM04HT141;H:DM5PR2201MB1514.namprd22.prod.outlook.com;FPR:;SPF:None;LANG:en; x-ms-office365-filtering-correlation-id: b400efce-b092-4c7d-4893-08d46b045be9 x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(22001)(201702061074)(5061506573)(5061507331)(1603103135)(1601125254)(1603101448)(1701031045);SRVR:BN3NAM04HT141; x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(432015087)(444000031);SRVR:BN3NAM04HT141;BCL:0;PCL:0;RULEID:;SRVR:BN3NAM04HT141; x-forefront-prvs: 02462830BE spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM X-OriginatorOrg: outlook.com X-MS-Exchange-CrossTenant-originalarrivaltime: 14 Mar 2017 18:03:02.9795 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Internet X-MS-Exchange-CrossTenant-id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN3NAM04HT141 X-OriginalArrivalTime: 14 Mar 2017 18:03:04.0463 (UTC) FILETIME=[3A30E1F0:01D29CED] X-Original-Sender: walter.heisenbug@outlook.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@outlook.com; spf=pass (google.com: domain of walter.heisenbug@outlook.com designates 65.55.90.234 as permitted sender) smtp.mailfrom=walter.heisenbug@outlook.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=outlook.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:31608 Archived-At: Currently to access a member type from a reference type means you have to d= o all the dancing with removing the reference.=20 template void f(T&& x) { =C2=A0=C2=A0=C2=A0 typedef typename std::remove_reference_t::member_type= mem; =C2=A0=C2=A0=C2=A0 mem y; =C2=A0=C2=A0=C2=A0 use(std::forward(x), y); } This could be simplified, if we allow to access the member types of a type = from a reference types: template void f(T&& x) { typedef typename T::member_type mem; mem y; use(std::forward(x), y); } I'm not aware of any potential problems, since the reference types don't ha= ve any member types, so there's no ambiguity with the existing code.=20 --=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/DM5PR2201MB151446C188D54CABB6E0FE9C87240%40DM5PR= 2201MB1514.namprd22.prod.outlook.com. .