Errors with exported defaulted class members

defaulted-exports.cpp

// Compile with: cl /std:c++17 /EHsc main.cpp

#include <list>
#include <string>
#include <memory>
#include <iostream>

#if defined(DLL_EXPORT)
#define EXPORT __declspec(dllexport)
#else
#define EXPORT
#endif

using std::string, std::list, std::unique_ptr, std::make_unique, std::move, std::cout;

class EXPORT Measure {
 public:
#if defined(FIXME)
   Measure() = default;
   Measure(const Measure&) = delete;
   Measure& operator=(const Measure&) = delete;
#endif

   struct Request {
     unique_ptr<string> a_string;
   };

   list<Request> request_list_;
};

int main() {
  Measure measure;
  Measure::Request req{make_unique<string>("test")};

  measure.request_list_.push_back(move(req));

  cout << *measure.request_list_.front().a_string;
}

/*
Compiling with /DDLL_EXPORT results in the below errors. Add /DFIXME to delete the default copy constructors/assignment to fix.
Note: Using the /Zc:dllexportInlines- flag with clang-cl.exe also fixes the problem.

main.cpp
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.24.28314\include\list(1264): error C2280: 'Measure::Request &Measure::Request::operator =(const Measure::Request &)': attempting to reference a deleted function
main.cpp(26): note: compiler has generated 'Measure::Request::operator =' here
main.cpp(26): note: 'Measure::Request &Measure::Request::operator =(const Measure::Request &)': function was implicitly deleted because a data member invokes a deleted or inaccessible function 'std::unique_ptr<std::string,std::default_delete<std::string>> &std::unique_ptr<std::string,std::default_delete<std::string>>::operator =(const std::unique_ptr<std::string,std::default_delete<std::string>> &)'
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.24.28314\include\memory(1913): note: 'std::unique_ptr<std::string,std::default_delete<std::string>> &std::unique_ptr<std::string,std::default_delete<std::string>>::operator =(const std::unique_ptr<std::string,std::default_delete<std::string>> &)': function was explicitly deleted
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.24.28314\include\list(1273): note: see reference to function template instantiation 'void std::list<Measure::Request,std::allocator<Measure::Request>>::_Assign_cast<Measure::Request&,_Iter>(_UIter,const _UIter)' being compiled
        with
        [
            _Iter=std::_List_unchecked_const_iterator<std::_List_val<std::_List_simple_types<Measure::Request>>,std::_Iterator_base0>,
            _UIter=std::_List_unchecked_const_iterator<std::_List_val<std::_List_simple_types<Measure::Request>>,std::_Iterator_base0>
        ]
*/