Goal 1: Every UB (yes, all ~200 of them, we’ll give the list towards the end of this post) must either be documented as having some defined behavior, be diagnosed with a fatal compiler error, or else — as a last resort — have a sanitizer that detects that UB at runtime.

Goal 2: Every UB must either be documented as having some defined behavior, be diagnosed with a fatal compiler error, or else have an optional mitigation mechanism that meets the requirements above.