Created attachment 27532 [details] test case Hi all, I hope this is not a bogus bug report, I apologize if there is something I misunderstood. I observed the following with both 4.7.0 and "4.8": g++-mp-4.7 (MacPorts gcc47 4.7.0_3) 4.7.0 Copyright (C) 2012 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. g++-mp-4.8 (MacPorts gcc48 4.8-20120527_1) 4.8.0 20120527 (experimental) Copyright (C) 2012 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. In the following example, I import a type name from a templates struct with "using", and do the same with "typedef". The latter works, but "using" does not seem to find the definition. clang finds it though (but then again, my understanding might be wrong). If "function" is not templated, there is no problem. $ cat foo.cc template <typename T> struct context { typedef int type; }; template <typename T> void function() { using ctx1 = context<T>; typename ctx1::type f1; typedef context<T> ctx2; typename ctx2::type f2; } int main() { function<int>(); } $ g++-mp-4.8 -Wall -std=c++11 foo.cc foo.cc: In instantiation of 'void function() [with T = int]': foo.cc:19:17: required from here foo.cc:11:23: error: no type named 'type' in 'using ctx1 = struct context<T>' typename ctx1::type f1; ^ foo.cc:14:23: warning: unused variable 'f2' [-Wunused-variable] typename ctx2::type f2; ^
I think it's valid, CC'ing Dodji for confirmation.
(In reply to comment #1) > I think it's valid, CC'ing Dodji for confirmation. Any news?
Sorry, I am getting to this just now.
> I think it's valid, CC'ing Dodji for confirmation. I agree this is a bug. I am looking into it.
A candidate patch was sent to http://gcc.gnu.org/ml/gcc-patches/2012-08/msg01111.html.
Dodji, time to ping? ;)
"paolo.carlini at oracle dot com" <gcc-bugzilla@gcc.gnu.org> a écrit: > Dodji, time to ping? ;) Right: http://gcc.gnu.org/ml/gcc-patches/2012-10/msg00766.html. :)
Author: dodji Date: Wed Oct 10 10:43:53 2012 New Revision: 192304 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192304 Log: PR c++/53540 - using fails to be equivalent to typedef In the example of this problem report, during the substituting of int into 'function', tsubst_aggr_type fails for the alias ctxt1. This is because TYPE_TEMPLATE_INFO looks for the TEMPLATE_INFO of the ctxt1 alias at the wrong place and was wrongly finding it to be NULL. Namely, it was looking for it in the DECL_TEMPLATE_INFO of the declaration of the type -- as if ctxt1 was an alias template specialization -- rather than looking for it in its CLASSTYPE_TEMPLATE_INFO. Fixed thus. The other hunks of the patch are a cleanup to make a better use of alias_template_specialization_p. Bootstrapped and tested on x86_64-unknown-linux-gnu against trunk. gcc/cp * cp-tree.h (TYPE_TEMPLATE_INFO): For an alias that is not an instance of alias template, don't look for its TEMPLATE_INFO in its declaration. (alias_template_specialization_p): Take const_tree. * pt.c (alias_template_specialization_p): Take a const_tree. Don't call primary_template_instantiation_p. (primary_template_instantiation_p): Call alias_template_specialization_p. gcc/testsuite/ * g++.dg/cpp0x/alias-decl-24.C: New test. Added: trunk/gcc/testsuite/g++.dg/cpp0x/alias-decl-24.C Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/cp-tree.h trunk/gcc/cp/pt.c trunk/gcc/testsuite/ChangeLog
Fixed in trunk (4.8)
*** Bug 54309 has been marked as a duplicate of this bug. ***