[clang-tidy] Modernize function parameters using `std::span<T>` where applicable

[SunBlack]

We often use std::vector instead of std::array in our code so that we don't have to template the methods. With C++20 and std::span, there is an elegant alternative for this. Therefore, it would be useful to have a check that recognizes when the container itself is irrelevant and code can be written more generically. Here is a code example that shows how using std::span eliminates the need for the template:

#include <iostream>
#include <span>
#include <vector>

constexpr int sum(const std::span<const int>& values)
{
    int sum = 0;
    for(auto value : values)
    {
        sum += value;
    }
    return sum;
}

int main()
{
    constexpr auto values1 = std::to_array({0, 2, 1, 3});
    const std::vector<int> values2{4, 7, 8, 9};

    std::cout << sum(values1) << '\n';
    std::cout << sum(values2) << '\n';
    return 0;
}

This check would be interesting in combination with #146607. In other words, with this suggestion, Clang-Tidy would recognize where generic containers can be passed, and with #146607, it would then recognize that, for example, a std::vector can be converted to a std::array because a method expects a std::span.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: SunBlack (SunBlack)

We often use `std::vector` instead of `std::array` in our code so that we don't have to template the methods. With C++20 and `std::span`, there is an elegant alternative for this. Therefore, it would be useful to have a check that recognizes when the container itself is irrelevant and code can be written more generically. Here is a code example that shows how using `std::span` eliminates the need for the template:

#include <iostream>
#include <span>
#include <vector>

int sum(const std::span<const int>& values)
{
    int sum = 0;
    for(auto value : values)
    {
        sum += value;
    }
    return sum;
}

int main()
{
    const auto values1 = std::to_array({0, 2, 1, 3});
    const std::vector<int> values2{4, 7, 8, 9};

    std::cout << sum(values1) << '\n';
    std::cout << sum(values2) << '\n';
    return 0;
}

[zwuis]

Someone tried: #140001.