> But I think you nailed it -- the compiler doesn't have to signal optimization "failures" back to the developer, but it has to for the constexpr case.
Is this true? Where do you see Clang emit a diagnostic in the example in the given article? (https://godbolt.org/g/HKcPFT)
You seem to be right -- at least "no diagnostics required" is mentioned a few times in $10.1.5 of N4700. To be honest, my comment is not from the article in the example, but from my own experience, and that is mostly with GCC 7.2.
Is this true? Where do you see Clang emit a diagnostic in the example in the given article? (https://godbolt.org/g/HKcPFT)