Runtime error: Undefined behavior due to unsigned integer overflow

[ztdwu]

EDIT: Nevermind, unsigned overflow is not undefined behaviour in the C++ standard. Not sure why ASAN is reporting it.

=== Original Comment: === The overflow error:

./docopt_util.h:96:46: runtime error: unsigned integer overflow: 15755298069831242297 + 3304135864781666520 cannot be represented in type 'unsigned long'
./docopt_util.h:96:34: runtime error: unsigned integer overflow: 13828916662110822956 + 17646836532054932864 cannot be represented in type 'unsigned long'

Compiled with clang 3.7 and ASAN:

clang++ docopt.cpp -c -o docopt.o -std=c++11 -Wall -Wextra -pedantic -Wcast-align -Wconversion -Wformat=2 -Wformat-nonliteral -Wlogical-op -Wmissing-format-attribute -Wnon-virtual-dtor -Wsign-conversion -fsanitize=undefined -fsanitize=integer
clang++ docopt-test.cpp docopt.o -std=c++11 -fsanitize=undefined -fsanitize=integer  

The driver program:

#include "docopt.h"

static auto USAGE = R"(
    Usage:
      prog --version

    Options:
      -h --help                 Show this screen.
)";

int main(const int argc, const char *const argv[]) {
    const auto args = docopt::docopt(USAGE,
                                     { argv + 1, argv + argc },
                                     true, "Bake 0.1");
}