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      font-size: 12px;" lang="x-unicode">Dear developers,
      <br>
      <br>
      unfortunately I cannot use Dune anymore. (The last successful run
      is weeks ago, so I do not know when the error started to appear).
      <br>
      <br>
      1) When I download the stable version Dune 2.4.1 I cannot use
      dune-pdelab,
      <br>
      <br>
      ERROR: version mismatch.
      <br>
             dune-pdelab requires dune-common >= 3.0,
      <br>
      <br>
      2) When I use the git version of the following modules
      <br>
      <br>
      dune-alugrid   dune-grid        dune-localfunctions  dune-typetree
      <br>
      dune-common    dune-grid-howto  dune-pdelab
      <br>
      dune-geometry  dune-istl        dune-pdelab-howto
      <br>
      <br>
      and run "dune-common/bin/dunecontrol all" I also get an error:
      <br>
      <br>
      -----------------------
      <br>
      Scanning dependencies of target dunecommon
      <br>
      [  7%] Building CXX object
      dune/common/CMakeFiles/dunecommon.dir/debugallocator.cc.o
      <br>
      [ 14%] Building CXX object
      dune/common/CMakeFiles/dunecommon.dir/dynmatrixev.cc.o
      <br>
      [ 21%] Building CXX object
      dune/common/CMakeFiles/dunecommon.dir/exceptions.cc.o
      <br>
      [ 28%] Building CXX object
      dune/common/CMakeFiles/dunecommon.dir/fmatrixev.cc.o
      <br>
      [ 35%] Building CXX object
      dune/common/CMakeFiles/dunecommon.dir/ios_state.cc.o
      <br>
      [ 42%] Building CXX object
      dune/common/CMakeFiles/dunecommon.dir/parametertree.cc.o
      <br>
      In file included from
      /home/diening/dune/dune-common/dune/common/fvector.hh:16:0,
      <br>
                       from
      /home/diening/dune/dune-common/dune/common/parametertree.hh:26,
      <br>
                       from
      /home/diening/dune/dune-common/dune/common/parametertree.cc:18:
      <br>
      /home/diening/dune/dune-common/dune/common/typetraits.hh:521:62:
      error: ‘decay_t’ is not a member of ‘std’
      <br>
         struct IsIntegralConstant : public
      Imp::IsIntegralConstant<std::decay_t<T>>
      <br>
                                                                    ^
      <br>
      /home/diening/dune/dune-common/dune/common/typetraits.hh:521:62:
      error: ‘decay_t’ is not a member of ‘std’
      <br>
      /home/diening/dune/dune-common/dune/common/typetraits.hh:521:75:
      error: template argument 1 is invalid
      <br>
         struct IsIntegralConstant : public
      Imp::IsIntegralConstant<std::decay_t<T>>
      <br>
      ^
      <br>
      /home/diening/dune/dune-common/dune/common/typetraits.hh:521:76:
      error: expected ‘{’ before ‘>’ token
      <br>
         struct IsIntegralConstant : public
      Imp::IsIntegralConstant<std::decay_t<T>>
      <br>
      ^
      <br>
      /home/diening/dune/dune-common/dune/common/typetraits.hh:521:76:
      error: expected unqualified-id before ‘>’ token
      <br>
      make[2]: ***
      [dune/common/CMakeFiles/dunecommon.dir/parametertree.cc.o] Error 1
      <br>
      make[1]: *** [dune/common/CMakeFiles/dunecommon.dir/all] Error 2
      <br>
      make: *** [all] Error 2
      <br>
      --- Failed to build dune-common ---
      <br>
      Terminating dunecontrol due to previous errors!
      <br>
      -----------------------------
      <br>
      <br>
      How can I resolve this problem?
      <br>
      <br>
      Best wishes,
      <br>
      <br>
      Lars
      <br>
      <br>
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