[Boost-bugs] [Boost C++ Libraries] #12621: property_tree::read_json does not work with BOOST_BIND_NO_PLACEHOLDERS

Subject: [Boost-bugs] [Boost C++ Libraries] #12621: property_tree::read_json does not work with BOOST_BIND_NO_PLACEHOLDERS
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-11-24 14:35:16

#12621: property_tree::read_json does not work with BOOST_BIND_NO_PLACEHOLDERS
------------------------------+---------------------------
 Reporter:  ja2222ja@…        |      Owner:  cornedbee
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  property_tree
  Version:  Boost 1.61.0      |   Severity:  Regression
 Keywords:                    |
------------------------------+---------------------------
 Minimal code example:
 {{{
 #define BOOST_BIND_NO_PLACEHOLDERS
 #include <boost/property_tree/json_parser.hpp>
 #include <functional>
 using namespace std::placeholders;

 int main () {
     boost::property_tree::ptree pt;
     boost::property_tree::read_json("lol", pt);
 }
 }}}

 Visual Studio 2015 Update 3 with v120 toolkit generates:
 {{{
 \lib\native\include\boost\bind\bind.hpp(319): error C2664: 'void
 boost::_mfi::mf1<void,boost::property_tree::json_parser::detail::standard_callbacks<Ptree>,char>::operator
 ()(T *,A1) const' : cannot convert argument 2 from 'std::_Ph<1>' to 'char'
 1>          with
 1>          [
 1>              Ptree=boost::property_tree::ptree
 1>  ,
 T=boost::property_tree::json_parser::detail::standard_callbacks<boost::property_tree::ptree>
 1>  ,            A1=char
 1>          ]
 1>          No user-defined-conversion operator available that can perform
 this conversion, or the operator cannot be called
 }}}

 First affected version: 1.59 [which introduces the new json parser]

 My investigation shows that
 {{{property_tree::json_parser::detail::standard_callbacks::operator()}}}
 uses unqualified  {{{_1}}} symbol. Since {{{#define
 BOOST_BIND_NO_PLACEHOLDERS}}} is used, compiler don't know nothing about
 {{{_1}}}.

 Error msg generated in msvc shows that {{{boost::bind}}} is messed up with
 {{{std::placeholders::_1}}}. The problem might be causes by no two-phase-
 lookup in {{{cl}}}. {{{using namespace std::placeholders}}} affects
 mentioned {{{_1}}} usage in {{{operator()}}} since lookup for non
 dependent {{{_1}}} is done later. Fixing issue in boost should workaround
 the msvc issue.

 Please note that without {{{#define BOOST_BIND_NO_PLACEHOLDERS}}}
 everything works ok.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12621>
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