And you can easily do a macro check and define a custom thing that's either assert(0) or unreachable() depending on the build type. But you still need unreachab

And you can easily do a macro check and define a custom thing that's either assert(0) or unreachable() depending on the build type. But you still need unreachable() to exist to do that. (and under -fsanitize=undefined you get an error for unreachable() too)