> I think WG21 has been violently against adding additional UB to the language, because of some hacker news articles a decade ago about people being alarmed at null pointer checks being elided or things happening that didn’t match their expectation in signed int overflow or whatever.

Huh, didn't expect the no-UB sentiment to have extended that far back!

> Regarding “not pan out”: I think the overhead of noexcept for the single function call case is fine, and inlining is and has always been the issue.

Do you know if the other major compilers also face similar issues?