boost::span cannot be constructed with iterators

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
cpp
Domain
backend

Research direction

Start with boost/core/span.hpp and reproduce the iterator construction example from the issue using the linked Godbolt case. Compare the supported boost::span constructors with the std::span behavior described in the cppreference link; done means the reported iterator form is supported without the pointer workaround.

Written by the indexing model from the issue text.

Description

std::span constructors 2 and 3 of cppreference.com documentation support generic iterators, while boost::span accepts only pointers. A possible workaround is to apply the operators &* to the iterators.

https://godbolt.org/z/sjEozr6M5

#include <span>
#include <boost/core/span.hpp>

#include <vector>

void foo(const std::vector<int>& v) {
    const auto std_span = std::span<const int>(v.begin(), v.end()); // fine
    // const auto boost_span = boost::span<const int>(v.begin(), v.end()); // broken
    const auto boost_span = boost::span<const int>(&*v.begin(), &*v.end()); // fine with hack
}
Dominant language
C++
Stars
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Forks
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