src/MonitoredSharedMemory.cc:46:32: error: possibly dangling reference to a temporary

Followup to

• https://github.com/rr-debugger/rr/issues/3483

/home/jdanek/repos/rr/src/MonitoredSharedMemory.cc: In static member function ‘static void rr::MonitoredSharedMemory::maybe_monitor(rr::RecordTask*, const std::string&, const rr::AddressSpace::Mapping&, int, uint64_t)’:
/home/jdanek/repos/rr/src/MonitoredSharedMemory.cc:46:32: error: possibly dangling reference to a temporary [-Werror=dangling-reference]
   46 |   const AddressSpace::Mapping& shared =
      |                                ^~~~~~
/home/jdanek/repos/rr/src/MonitoredSharedMemory.cc:47:29: note: the temporary was destroyed at the end of the full expression ‘rr::Session::steal_mapping(remote, (* & m), std::shared_ptr<rr::MonitoredSharedMemory>((* & std::move<shared_ptr<rr::MonitoredSharedMemory>&>(result))))’
   47 |       Session::steal_mapping(remote, m, std::move(result));
      |       ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors

/home/jdanek/repos/rr/src/Session.cc: In static member function ‘static void rr::Session::make_private_shared(rr::AutoRemoteSyscalls&, rr::AddressSpace::Mapping)’:
/home/jdanek/repos/rr/src/Session.cc:618:32: error: possibly dangling reference to a temporary [-Werror=dangling-reference]
  618 |   const AddressSpace::Mapping& new_m = steal_mapping(remote2, m);
      |                                ^~~~~
/home/jdanek/repos/rr/src/Session.cc:618:53: note: the temporary was destroyed at the end of the full expression ‘rr::Session::steal_mapping(remote2, m, std::shared_ptr<rr::MonitoredSharedMemory>(nullptr))’
  618 |   const AddressSpace::Mapping& new_m = steal_mapping(remote2, m);
      |                                        ~~~~~~~~~~~~~^~~~~~~~~~~~
cc1plus: all warnings being treated as errors

Read src/MonitoredSharedMemory.cc around lines 46-47 and src/Session.cc around line 618, then inspect the return value and lifetime behavior of Session::steal_mapping. Reproduce the compiler diagnostics with warnings treated as errors and verify that both dangling-reference warnings are resolved without introducing new build failures.