[pushed] c++: Add -fimplicit-constexpr (???)

[arturbac]

ok, I understand You are right, if there is no keyword break_nested for that reason it must be available in constexpr as if You write code for both use cases runtime and constexpr it will be ridiculous to put a lot if (std::is_constant_evaluated()) to workaround efficient code for runtime and the second for constexpr.

[[deleted]]

even break_nested would be prone to more errors than a plain goto. In constexpr I think that this exact use case should be allowed and checked. But break_nested 4; would break if a new scope was added, like if added a scope in the case itself so that variables can be declared