Volumes: rearrange definition of classes (c++20, gcc13,ROOT 6.28/04)

[andresailer]

Parameterisation uses PlacedVolume, root cling dictionary complains about incomplete class needed for vector

BEGINRELEASENOTES

• Volumes.h: rearrange implementation of classes, fix needed for gcc13/root 6.28/04, c++20

ENDRELEASENOTES

This was the error message

[ 14%] Generating G__DD4hepGeo.cxx, ../lib/G__DD4hepGeo_rdict.pcm
In file included from input_line_4:2:
In file included from /build/jenkins/workspace/lcg_nightly_pipeline/install/dev3lhcb/ROOT/HEAD/x86_64-el9-gcc13-opt/include/Rtypes.h:193:
In file included from /build/jenkins/workspace/lcg_nightly_pipeline/install/dev3lhcb/ROOT/HEAD/x86_64-el9-gcc13-opt/include/TGenericClassInfo.h:22:
In file included from /cvmfs/sft.cern.ch/lcg/releases/gcc/13.1.0-b3d18/x86_64-el9/bin/../lib/gcc/x86_64-pc-linux-gnu/13.1.0/../../../../include/c++/13.1.0/vector:66:
/cvmfs/sft.cern.ch/lcg/releases/gcc/13.1.0-b3d18/x86_64-el9/bin/../lib/gcc/x86_64-pc-linux-gnu/13.1.0/../../../../include/c++/13.1.0/bits/stl_vector.h:367:35: error: arithmetic on a pointer to an incomplete type 'dd4hep::PlacedVolume'
                      _M_impl._M_end_of_storage - _M_impl._M_start);
                      ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
/cvmfs/sft.cern.ch/lcg/releases/gcc/13.1.0-b3d18/x86_64-el9/bin/../lib/gcc/x86_64-pc-linux-gnu/13.1.0/../../../../include/c++/13.1.0/bits/stl_vector.h:526:7: note: in instantiation of member function 'std::_Vector_base<dd4hep::PlacedVolume, std::allocator<dd4hep::PlacedVolume> >::~_Vector_base' requested here
      vector() = default;
      ^
/build/jenkins/workspace/lcg_nightly_pipeline/build/frameworks/DD4hep-master/src/DD4hep/master/DDCore/include/DD4hep/Volumes.h:142:44: note: in defaulted default constructor for 'std::vector<dd4hep::PlacedVolume, std::allocator<dd4hep::PlacedVolume> >' first required here
      std::vector<PlacedVolume> placements {  };
                                           ^
/build/jenkins/workspace/lcg_nightly_pipeline/build/frameworks/DD4hep-master/src/DD4hep/master/DDCore/include/DD4hep/Volumes.h:44:10: note: forward declaration of 'dd4hep::PlacedVolume'
  class  PlacedVolume;
         ^
In file included from input_line_4:2:
In file included from /build/jenkins/workspace/lcg_nightly_pipeline/install/dev3lhcb/ROOT/HEAD/x86_64-el9-gcc13-opt/include/Rtypes.h:193:
In file included from /build/jenkins/workspace/lcg_nightly_pipeline/install/dev3lhcb/ROOT/HEAD/x86_64-el9-gcc13-opt/include/TGenericClassInfo.h:22:
In file included from /cvmfs/sft.cern.ch/lcg/releases/gcc/13.1.0-b3d18/x86_64-el9/bin/../lib/gcc/x86_64-pc-linux-gnu/13.1.0/../../../../include/c++/13.1.0/vector:66:
/cvmfs/sft.cern.ch/lcg/releases/gcc/13.1.0-b3d18/x86_64-el9/bin/../lib/gcc/x86_64-pc-linux-gnu/13.1.0/../../../../include/c++/13.1.0/bits/stl_vector.h:367:35: error: arithmetic on a pointer to an incomplete type 'dd4hep::PlacedVolume'
                      _M_impl._M_end_of_storage - _M_impl._M_start);
                      ~~~~~~~~~~~~~~~~~~~~~~~~~ ^
/cvmfs/sft.cern.ch/lcg/releases/gcc/13.1.0-b3d18/x86_64-el9/bin/../lib/gcc/x86_64-pc-linux-gnu/13.1.0/../../../../include/c++/13.1.0/bits/stl_vector.h:526:7: note: in instantiation of member function 'std::_Vector_base<dd4hep::PlacedVolume, std::allocator<dd4hep::PlacedVolume> >::~_Vector_base' requested here
      vector() = default;
      ^
/build/jenkins/workspace/lcg_nightly_pipeline/build/frameworks/DD4hep-master/src/DD4hep/master/DDCore/include/DD4hep/Volumes.h:142:44: note: in defaulted default constructor for 'std::vector<dd4hep::PlacedVolume, std::allocator<dd4hep::PlacedVolume> >' first required here
      std::vector<PlacedVolume> placements {  };
                                           ^
/build/jenkins/workspace/lcg_nightly_pipeline/build/frameworks/DD4hep-master/src/DD4hep/master/DDCore/include/DD4hep/Volumes.h:44:10: note: forward declaration of 'dd4hep::PlacedVolume'
  class  PlacedVolume;
         ^
Error: /build/jenkins/workspace/lcg_nightly_pipeline/install/dev3lhcb/ROOT/HEAD/x86_64-el9-gcc13-opt/bin/rootcling: compilation failure (/build/jenkins/workspace/lcg_nightly_pipeline/build/frameworks/DD4hep-master/src/DD4hep-master-build/DDCore/../lib/G__DD4hepGeoac3244d7d3_dictUmbrella.h)