Re: [Boost-bugs] [Boost C++ Libraries] #11927: optional_test_swap.cpp: In C++11 mode, std::swap should have a noexcept specification

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #11927: optional_test_swap.cpp: In C++11 mode, std::swap should have a noexcept specification
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-02-15 09:04:09

#11927: optional_test_swap.cpp: In C++11 mode, std::swap should have a noexcept
specification
--------------------------------------------+-----------------------
  Reporter:  Aparna Kumta <aparna.kumta@…>  |      Owner:  fcacciola
      Type:  Bugs                           |     Status:  new
 Milestone:  To Be Determined               |  Component:  optional
   Version:  Boost Development Trunk        |   Severity:  Problem
Resolution:                                 |   Keywords:
--------------------------------------------+-----------------------

Comment (by anonymous):

 In C++11 std::swap has the following noexcept specification (20.2.2
 [utility.swap]):

 {{{
 noexcept(is_nothrow_move_constructible<T>::value &&
          is_nothrow_move_assignable<T>::value
 }}}

 Because {{{optional_swap_test::class_without_default_ctor}}} has a
 throwing move assignment, therefore the non-specialized instantiation of
 std::swap for {{{class_without_default_ctor}}} is {{{noexcept(false)}}}.
 The explicit specialization in file {{{optional_test_swap.cpp}}} is
 correct not to provide {{{noexcept}}} specification.

 My guess is that the compiler gets the {{{is_nothrow_move_assignable}}}
 wrong.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11927#comment:2>
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