ust before the review of Outcome 2.0, I had mooted a number of semantic and compile time performance
improvements to <code>&lt;system_error&gt;</code> with the proposal that we mildly break Boost.System with
improvements and see how badly real world code broke in response. This was not widely
accepted at that time (though they have been since incorporated into Boost.System, and proposed
defect remedies for <code>&lt;system_error&gt;</code> for C++ 23). I therefore wrote <a href="https://ned14.github.io/stat