From 9102530679531978946 X-Google-Thread: f78e5,cc5f8341523fbc66 X-Google-NewGroupId: yes X-Google-Attributes: gid7894ca11fe,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!news.giganews.com.POSTED!not-for-mail NNTP-Posting-Date: Sat, 28 Aug 2010 22:40:01 -0500 Return-Path: To: (Usenet) From: "Johannes Schaub (litb)" Newsgroups: comp.std.c++ Subject: Re: FCD issue: Contradiction about dependency of "operator T()" Followup-To: comp.std.c++ Organization: T-Online Sender: cppmods@cs.rpi.edu Approved: james.dennett@gmail.com Message-ID: References: <5176b18a-9065-4dd2-83c5-896f78f19dbd@x42g2000yqx.googlegroups.com> Content-Type: text/plain; charset="ISO-8859-1" X-Original-Date: Sat, 28 Aug 2010 02:07:51 +0200 X-Submission-Address: std-c++@netlab.cs.rpi.edu Date: Sat, 28 Aug 2010 22:30:25 CST Lines: 72 X-Usenet-Provider: http://www.giganews.com X-Trace: sv3-p5duYMxH9MKMzPEne1yrqCyUPEKeZD0V5B7uFoihzJ8GqQX9enISrSQFA4lxHqaQneK0GcoHOQtawnX!wm5Z/NSrTjtp7CdEY8M0fplmo5H+FzHDwCnXV/ABpxUsQ+j6jp5IpmqKTcvs X-Complaints-To: abuse@giganews.com X-DMCA-Notifications: http://www.giganews.com/info/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Xref: g2news1.google.com comp.std.c++:2923 David Krauss wrote: > On Aug 27, 2:28 pm, "Johannes Schaub (litb)" > wrote: >> The FCD changed the text of 14.7.2/1 about the Status of dependency of a > > Replace all 14.7.x with 14.6.x. > I'm sorry, I was using the document that hilights the changes (3090) instead of the FCD itself (3092). Next time I take care :) >> function call to read like >> >> "In an expression of the form: >> >> postfix-expression ( expression-list[opt] ) >> >> where the postfix-expression is an unqualified-id , the unqualified-id >> denotes a dependent name if and only if any of the expressions in the >> expression-list is a type-dependent expression (14.7.2.2)." >> >> This rule contradicts 14.7.2.2/3 which says >> >> "An id-expression is type-dependent if it contains: >> - a conversion-function-id that specifies a dependent type," > > Why are conversion functions particularly significant? I think the > idea here is that such a function may be named by a typedef or > dependent typename. > Yes, a conversion function can be named by a typedef. Two conversion function names are equal if the type specified in them is the same (clause 3 - no lexical comparison, but semantical comparison is done). > The first thing in that list is > > - an identifier associated by name lookup with one or more > declarations declared with a dependent type > I skipped that, because the issue was with the thing i mentioned :) I probably should have indicated that somehow. > So if an argument is declared with dependent type, the function > identifier is associated with a dependent type by name lookup, hence > dependent. > But if I call "operator T()" there is no argument because the expression- list is absent. So we don't have an expression that is type-dependent, and this makes the name "operator T" non-dependent ("if and only if"). But 14.6.2.2/3 does make it dependent. This looks constradictory to me. Note that C++03 did not say "unqualified-id" but just "identifier" here, which did not include conversion function id's and thus is not affected by this issue. In any case, it should not make a difference for calls of kind "operator T()", because a dependent function call can never end up calling a member function of a dependent base class (DR #213). But there still is a contradiction, at least the way I interpret that wording. So, is a ". template" required in "operator T().foo<..>()" ? Yes, because it is dependent, or no because it is not? -- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@netlab.cs.rpi.edu] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]