[Boost-bugs] [Boost C++ Libraries] #12249: Wrong operator|() overload being found on multiple platforms & causing compilation failure

Subject: [Boost-bugs] [Boost C++ Libraries] #12249: Wrong operator|() overload being found on multiple platforms & causing compilation failure
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-06-02 15:47:39

#12249: Wrong operator|() overload being found on multiple platforms & causing
compilation failure
------------------------------+------------------------
 Reporter:  rob.desbois@…     |      Owner:  neilgroves
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  range
  Version:  Boost 1.61.0      |   Severity:  Problem
 Keywords:                    |
------------------------------+------------------------
 When using the pipe syntax (operator| overloads) for range adaptors I'm
 finding that the overloads taking replace_holder are being incorrectly
 selected when using other adaptors over a range exposing abstract base
 class references.

 I can reproduce this with filtered, transformed and indexed adaptors; on
 Clang, gcc & MSVC; and with Boost 1.57 and 1.61.

 The minimal failing testcase is attached, and compiles fine when the
 replaced.hpp include is commented out.

 The error I get with clang for the attached file is:
 {{{
 In file included from invoke-boost-failure.cpp:1:
 In file included from /usr/include/boost/range/adaptor/indexed.hpp:23:
 /usr/include/boost/range/adaptor/argument_fwd.hpp:36:15: error: field type
 'Base' is an abstract class
             T val1, val2;
               ^
 /usr/include/boost/range/adaptor/replaced.hpp:93:39: note: in
 instantiation of template class 'boost::range_detail::holder2<Base>'
 requested here
         class replace_holder : public holder2<T>
                                       ^
 invoke-boost-failure.cpp:17:33: note: in instantiation of template class
 'boost::range_detail::replace_holder<Base>' requested here
     for (const auto& b : refs | boost::adaptors::indexed())
                                 ^
 invoke-boost-failure.cpp:8:13: note: unimplemented pure virtual method
 '~Base' in 'Base'
     virtual ~Base() = 0;
             ^
 In file included from invoke-boost-failure.cpp:1:
 In file included from /usr/include/boost/range/adaptor/indexed.hpp:23:
 /usr/include/boost/range/adaptor/argument_fwd.hpp:36:21: error: field type
 'Base' is an abstract class
             T val1, val2;
                     ^
 2 errors generated.
 }}}


 I can work around this by using the function call syntax for adaptors, but
 I can't suggest a fix as I don't understand why that overload is being
 selected at all.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12249>
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