Hi, it looks like using boost::multi_index::member<> crashes MSVC 2015 RTM when a const-qualified type is passed to it as the 2nd argument, but the member is actually non-const. #include <boost\multi_index_container.hpp> #include <boost\multi_index\member.hpp> #include <boost\multi_index\indexed_by.hpp> #include <boost\multi_index\ordered_index.hpp> struct X { int number; // non-const }; using namespace boost::multi_index; int main() { typedef multi_index_container<X, indexed_by<ordered_unique<member<X, const int, &X::number> > > > C; C c; c.find(1); // C1001 return 0; } ...\include\boost\multi_index\member.hpp(65): fatal error C1001: An internal error has occurred in the compiler. (compiler file 'f:\dd\vctools\compiler\utc\src\p2\main.c', line 246) I found the following on a related subject, but I'm not sure whether this is a separate issue or not. http://www.boost.org/development/tests/master/developer/output/teeks99-08l-w... https://connect.microsoft.com/VisualStudio/feedback/details/1577162/vc-inter... https://groups.google.com/forum/#!topic/boost-devel-archive/gi-xGnCkvPI Thanks, Filip