Boost C++ Libraries: Ticket #9647: BOOST_MPL_ASSERT_RELATION fails to properly handle unsigned types

summary changed

viboes — Sun, 25 Jan 2015 15:22:07 GMT

summary boost_MPL_ASSERT_RELATION fails to properly handle unsigned types → BOOST_MPL_ASSERT_RELATION fails to properly handle unsigned types

Is this a problem with Clang, Boost.Mpl or Boost.Integer library?

owner, status changed

viboes — Sun, 25 Jan 2015 15:47:26 GMT

owner changed from Daryle Walker to viboes
status new → assigned

Robert Ramey — Sun, 22 Mar 2015 22:41:09 GMT

I'm thinking that this is libc++ version of limits.h

perhaps this is not the correct place to report this.

Robert Ramey

Robert Ramey — Mon, 23 Mar 2015 18:23:55 GMT

I looked into this a little bit more.

First of all, my original guess about problematic type promotions was wrong - I don't think there is any issue with libc++ or anything else in the standard library.

The following test program illustrates my

#include <boost/integer_traits.hpp>
#include <boost/mpl/assert.hpp>
BOOST_MPL_ASSERT_RELATION(
    (boost::integer_traits<unsigned long>::const_max),
    >,
    (boost::integer_traits<unsigned char>::const_max)
); // compile error under clang
enum { x  = (
    (boost::integer_traits<unsigned long>::const_max)
    >
    (boost::integer_traits<unsigned char>::const_max)
    )
}; // compiles OK - can't figure out why
constexpr bool result = (
    (boost::integer_traits<unsigned long>::const_max)
    >
    (boost::integer_traits<unsigned char>::const_max)
    ); // compiles fine
static_assert(result, "compilation error");
int main(int argc, char * argv[]){
    return ! (boost::integer_traits<unsigned long>::const_max > boost::integer_traits<unsigned char>::const_max);
}

So I believe this is an issue with MPL_ASSERT_RELATION. I've believe the problem is found in boost/mpl/assert.hpp at the line #329: It's probably deeper than this but I didn't trace it further

Robert Ramey

component changed

viboes — Sat, 04 Apr 2015 21:29:22 GMT

component integer → mpl

owner, status changed

viboes — Sat, 04 Apr 2015 21:29:55 GMT

owner changed from viboes to Aleksey Gurtovoy
status assigned → new