id summary reporter owner description type status milestone component version severity resolution keywords cc 797 doc of placeholer expression requirements incomplete cppljevans david_abrahams "{{{ he 3 expression requirements on: http://www.boost.org/libs/mpl/doc/refmanual/placeholder-expression.html make no mention that X should have a nested type typedef. IOW, X must be a metafunction as defined here: http://www.boost.org/libs/mpl/doc/refmanual/metafunction.html However, I believe it should since I'm getting compile-time error messages without the nested typedef. }}}" Bugs closed None None Invalid