pop_back on an empty container is a programmer error. A pop_back defined as noop would only leave the program in a slightly more defined state, but quite likel

pop_back on an empty container is a programmer error. A pop_back defined as noop would only leave the program in a slightly more defined state, but quite likely you can't really reason about the behavior of the program after. And implementations would not be allowed to diagnose the erroneous pop_back at runtime. IMO if pop_back had a defined behavior, it should be immediate termination of the program, with a diagnostic message. The standard does this for some erroneous behaviors, like failing to join or detach a thread before destruction, failing to catch an exception in various contexts or throwing an exception during stack unwinding. Undefined behavior already allows the behavior of terminating the program with a diagnostic message, and some implementation provide options to have this behavior. It might not be very discoverable though, which is a pity. It would be nice if some higher level build tools provided easier options for "fortifying" C and C++ code, but I doubt that there are options that uniformly apply across compilers and standard library implementations.