Is there a good reason for the following #ifdef in "concept_check.hpp": template <class Concept> inline void function_requires(mpl::identity<Concept>* = 0) { #if !defined(NDEBUG) void (Concept::*x)() = BOOST_FPTR Concept::constraints; ignore_unused_variable_warning(x); #endif } ? It causes "concept_check_fail_expected" test to fail if compiled in "release mode"; see http://tinyurl.com/6u286. Any objections to removing it? -- Aleksey Gurtovoy MetaCommunications Engineering