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From: "ai.azuma at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/52374] New: [C++11] Fails to transform id-expression into dependent base member access in lambda expression
Date: Fri, 24 Feb 2012 16:50:00 -0000	[thread overview]
Message-ID: <bug-52374-4@http.gcc.gnu.org/bugzilla/> (raw)

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52374

             Bug #: 52374
           Summary: [C++11] Fails to transform id-expression into
                    dependent base member access in lambda expression
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ai.azuma@gmail.com


Created attachment 26742
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26742
Output of -v option and preprocessed file

In the lambda expression's compound statement, id-expressions referring to
non-static members should be transformed into class member access expressions
by prefixing `(*this).'. However, GCC fails the transformation when
id-expressions involved are qualified-ids and refer to dependent base members.

A test case is as follows;

////////////////////////////////////////////////////////////////////
struct B
{
  int get() const { return 42; }
};

template<typename X>
struct D
  : public X
{
  int get() const { return [this]() -> int { return X::get(); }(); }
};

int main()
{
  D<B> d;
  d.get();
}

////////////////////////////////////////////////////////////////////

For the above mentioned well-formed code, 4.7.0 20120218 (experimental) with
-std=c++11 complains as follows;

main.cpp: In instantiation of 'D<X>::get() const [with X = B]::<lambda()>':
main.cpp:10:29:   required from 'struct D<X>::get() const [with X =
B]::<lambda()>'
main.cpp:10:65:   required from 'int D<X>::get() const [with X = B]'
main.cpp:16:9:   required from here
main.cpp:10:60: error: cannot call member function 'int B::get() const' without
object

`X::get' in the lambda expression should be implicitly transformed into
`(*this).X::get', and the test case should compile successfully.


             reply	other threads:[~2012-02-24 16:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-24 16:50 ai.azuma at gmail dot com [this message]
2012-02-24 17:20 ` [Bug c++/52374] " redi at gcc dot gnu.org
2013-03-13  2:53 ` jason at gcc dot gnu.org
2013-03-17  2:42 ` jason at gcc dot gnu.org
2013-03-23 19:24 ` jason at gcc dot gnu.org

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