[Boost-bugs] [Boost C++ Libraries] #13137: boost::optional::operator*() doesn't have "const &&" overload, allowing incorrect usage

Subject: [Boost-bugs] [Boost C++ Libraries] #13137: boost::optional::operator*() doesn't have "const &&" overload, allowing incorrect usage
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2017-07-26 06:00:30

#13137: boost::optional::operator*() doesn't have "const &&" overload, allowing
incorrect usage
--------------------------------+-------------------------------
 Reporter:  for.gcc.bugzilla@…  |      Owner:  Fernando Cacciola
     Type:  Bugs                |     Status:  new
Milestone:  To Be Determined    |  Component:  optional
  Version:  Boost 1.65.0        |   Severity:  Problem
 Keywords:                      |
--------------------------------+-------------------------------
 {{{
 #include <boost/optional.hpp>

 const boost::optional<int> f()
 {
     return {1};
 }

 int main()
 {
     const int& ref = *f();
     // creates a boost::optional temporary
     // "*tmp" binds to "optional::operator*() const&"
     // "ref" starts pointing to internals of the returned temporary
     // temporary gets destroyed
     // we have a dangling reference
 }
 }}}

 at the same time, std::optional in C++17 does have
 {{{
 constexpr const T&& operator*() const &&;
 }}}
 [http://en.cppreference.com/w/cpp/utility/optional/operator* overload],
 which lets the code above work correctly.

-- 
Ticket URL: <https://svn.boost.org/trac10/boost/ticket/13137>
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