[Boost-bugs] [Boost C++ Libraries] #7675: BOOST_NO_DECLTYPE doesn't imply BOOST_NO_DECLTYPE_N3276 anymore

Subject: [Boost-bugs] [Boost C++ Libraries] #7675: BOOST_NO_DECLTYPE doesn't imply BOOST_NO_DECLTYPE_N3276 anymore
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-11-09 17:38:03

#7675: BOOST_NO_DECLTYPE doesn't imply BOOST_NO_DECLTYPE_N3276 anymore
-------------------------------+--------------------------------------------
 Reporter:  gromer@…           |       Owner:  johnmaddock
     Type:  Bugs               |      Status:  new        
Milestone:  To Be Determined   |   Component:  config     
  Version:  Boost 1.52.0       |    Severity:  Regression 
 Keywords:                     |  
-------------------------------+--------------------------------------------
 Here's a simple repro:

 {{{
 #define BOOST_NO_DECLTYPE

 #include <boost/suffix.hpp>

 #ifndef BOOST_NO_DECLTYPE_N3276
 #error "BOOST_NO_DECLTYPE should imply BOOST_NO_DECLTYPE_N3276"
 #endif
 }}}
 (I include only suffix.hpp so that the bug reproduces on any compiler; you
 can include boost/config.hpp instead, if you use a compiler that Boost
 detects as supporting N3276)

 This fails with Boost 1.52.0, but builds with 1.50.0 (I don't have 1.51.0
 handy to test, but from context I suspect it fails there too). This is a
 problem because utility/result_of.hpp, and possibly other Boost code,
 assumes decltype is permitted if BOOST_NO_DECLTYPE_N3276 is not defined;
 due to this bug, that code will continue to use decltype even when the
 user specifies BOOST_NO_DECLTYPE.

 I've attached a patch that fixes this specific issue, but note that it may
 reflect a more general problem with the handling of deprecated config
 macros.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7675>
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