id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
10493,"Since 1.56, any_range with non-reference references can cause UB",nofitserov@…,Neil Groves,"This must be related to #10360. This is a regression since 1.55.

When using any_range<T, category, T, ptrdiff_t>, mutable dereference() method returns mutable_reference_type_generator<T>::type, which becomes T&. So dereference() returns a dangling reference to an on-the-fly computed value.

See attached test case, which works with 1.55, and fails with -fsanitize=address on Clang 3.5 with 1.56.

{{{
#include <boost/range/any_range.hpp>
#include <boost/range/adaptor/transformed.hpp>
#include <cmath>
#include <iostream>

typedef boost::any_range<
    std::string,
    boost::forward_traversal_tag,
    std::string,
    std::ptrdiff_t
> range_t;

std::string f(std::string a)
{
    return a + ""!"";
}

int main()
{
    std::vector<std::string> v = {""a"", ""b""};
    range_t r = v | boost::adaptors::transformed(f);
    for (auto&& a : r)
        std::cout << a << std::endl;
    return 0;
}

}}}
",Bugs,assigned,Boost 1.64.0,range,Boost 1.62.0,Regression,,,p.omta@…