I recently looked into some proto failures on msvc-10 and traced them back to the use of decltype in the implementation of boost::result_of. The program below demonstrates the problem: // Uncomment the next line to make the problem go away //#define BOOST_NO_DECLTYPE #include <boost/utility/result_of.hpp> template<class X, class Y> struct pair {}; template<class Base> struct S; struct wrapper { template<class T> struct result; template<class This, typename That> struct result<This(That)> { typedef S<That> type; }; template<typename That> typename result<wrapper(That)>::type operator()(That) const { return 0; } }; template<class T> struct S { S(int = 0) {} typename boost::result_of<wrapper(pair<T, T>)>::type foo() { return 0; } }; int main() { S<int> s; } The use of decltype in result_of causes the compiler to recursively instantiate templates until it blows its stack. To make the problem go away, you must #define BOOST_NO_DECLTYPE. I suspect the real problem is in a buggy implementation of decltype on msvc-10. For the upcoming boost release, I suggest that we stick with the non-decltype implementation of result_of on msvc-10, or risk massively breaking users' code, not to mention proto, spirit and xpressive on that compiler. -- Eric Niebler BoostPro Computing http://www.boostpro.com