boost::system::errc enum is accepted as a value into result<int>

[ytimenkov]

Boost version 1.78.0

The shortest reproduction is:

#include <boost/system/result.hpp>

static_assert(boost::system::result<int>{boost::system::errc::invalid_argument}.has_error());

<source>:511:90: error: static assertion failed
  511 | static_assert(boost::system::result<int>{boost::system::errc::invalid_argument}.has_error());
      |               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
Compiler returned: 1

I use similar pattern extensively in the code with outcome and std::error_code , something like:

result<int> do_something(int count)
{
    if (count < 0)
        return std::errc::invalid_argument;
}

The fact that errc enum converts to value implicitly is really surprising (won't be surprised if it just didn't convert).

[pdimov]

A better fix for this would be making errc_t a scoped enum (#75), but for now, I'll disable the conversions to int on the result side.