David Abrahams wrote:
Yesterday someone on the user's list posted a message (http://article.gmane.org/gmane.comp.lib.boost.user/36884) about a "compilation error in the boost code:"
s-test.h:49: instantiated from here /usr/include/boost/archive/detail/oserializer.hpp:567: error: invalid application of 'sizeof' to incomplete type 'boost::STATIC_ASSERTION_FAILURE<false>' make: *** [stest] Error 1
and proceeded to try to analyze the BOOST_STATIC_ASSERT implementation to see what was wrong with it. Granted, most people figure out what a static assertion is supposed to be, but still, the error message gave no clue about what might have gone wrong... no clue to the user, and no clue to anyone reading his posting, unless they were going to look up the line in the source file... oops, I take it back. My copy of oserializer.hpp doesn't even have a line 567, and the posting doesn't indicate which version the user has.
For several releases now we've had a suite of static assertion tools that give far superior error messages to what BOOST_STATIC_ASSERT can provide (http://www.boost.org/doc/libs/1_35_0/libs/mpl/doc/refmanual/asserts.html). I think <radical-idea>it's time to deprecate BOOST_STATIC_ASSERT</radical-idea> or at *least* put a prominent note in its documentation directing people at the BOOST_MPL_ASSERT macros.
Thoughts?
I'm in two minds over this: yes we should direct people to the best that we have. However, once compilers start supporting a native static_assert we can redirect BOOST_STATIC_ASSERT to that and get *much* better messages (of course the MPL macros may do the same thing). The other issue is with MPL's messages: sorry Dave, but the first time I saw an MPL assertion failure, my immediate reaction was "what the heck is that?" :-( I've certainly no objection to updating the docs to refer to the MPL asserts as well though. What do others think? John.