memmove(args->begin_argv + extend, args->begin_argv + consume, args->endp - args->begin_argv + consume); // ← bug C code like this is why we can't have

memmove(args->begin_argv + extend, args->begin_argv + consume, args->endp - args->begin_argv + consume); // ← bug C code like this is why we can't have nice things. Arithmetic operation in the arguments of a dangerous function call with no explicit bounds check.