Type not shown

[mreininghaus]

In the following example, the type of x and y won't be shown in the output:

#include <ranges>
#include <print>

int main() {
  auto const i = std::views::iota(1, 21);
  auto const sq = i | std::views::transform([](auto x) { return x * x; });
  auto const trip =
      i | std::views::transform([](auto x) { return x * x * x; });

  auto const z = std::views::zip(i, sq, trip);

  auto x = std::size(i);
  auto y = std::size(sq);
  auto u = std::size(z);

  std::println("{} {} {}", x, y, u);

  return EXIT_SUCCESS;
}

The output reads:

#include <ranges>
#include <print>

int main()
{
  const std::ranges::iota_view<int, int> i = std::ranges::views::iota.operator()(1, 21);
      
  class __lambda_8_45
  {
    public: 
    template<class type_parameter_0_0>
    inline /*constexpr */ auto operator()(type_parameter_0_0 x) const
    {
      return x * x;
    }
    
    #ifdef INSIGHTS_USE_TEMPLATE
    template<>
    inline /*constexpr */ int operator()<int>(int x) const
    {
      return x * x;
    }
    #endif
    
    private: 
    template<class type_parameter_0_0>
    static inline /*constexpr */ auto __invoke(type_parameter_0_0 x)
    {
      return __lambda_8_45{}.operator()<type_parameter_0_0>(x);
    }
    public: 
    // inline /*constexpr */ __lambda_8_45() noexcept = default;
    // inline /*constexpr */ __lambda_8_45(const __lambda_8_45 &) noexcept = default;
    // inline /*constexpr */ __lambda_8_45(__lambda_8_45 &&) noexcept = default;
    // /*constexpr */ __lambda_8_45() = default;
    
  } __lambda_8_45{};
  
  const std::ranges::transform_view<std::ranges::iota_view<int, int>, __lambda_8_45> sq = std::ranges::views::__adaptor::operator|(i, static_cast<const std::ranges::views::__adaptor::_RangeAdaptor<std::ranges::views::_Transform>&>(std::ranges::views::transform).operator()(__lambda_8_45));
      
  class __lambda_10_33
  {
    public: 
    template<class type_parameter_0_0>
    inline /*constexpr */ auto operator()(type_parameter_0_0 x) const
    {
      return (x * x) * x;
    }
    
    #ifdef INSIGHTS_USE_TEMPLATE
    template<>
    inline /*constexpr */ int operator()<int>(int x) const
    {
      return (x * x) * x;
    }
    #endif
    
    private: 
    template<class type_parameter_0_0>
    static inline /*constexpr */ auto __invoke(type_parameter_0_0 x)
    {
      return __lambda_10_33{}.operator()<type_parameter_0_0>(x);
    }
    public: 
    // inline /*constexpr */ __lambda_10_33() noexcept = default;
    // inline /*constexpr */ __lambda_10_33(const __lambda_10_33 &) noexcept = default;
    // inline /*constexpr */ __lambda_10_33(__lambda_10_33 &&) noexcept = default;
    // /*constexpr */ __lambda_10_33() = default;
    
  } __lambda_10_33{};
  
  const std::ranges::transform_view<std::ranges::iota_view<int, int>, __lambda_10_33> trip = std::ranges::views::__adaptor::operator|(i, static_cast<const std::ranges::views::__adaptor::_RangeAdaptor<std::ranges::views::_Transform>&>(std::ranges::views::transform).operator()(__lambda_10_33));
  const std::ranges::zip_view<std::ranges::iota_view<int, int>, std::ranges::transform_view<std::ranges::iota_view<int, int>, __lambda_8_45>, std::ranges::transform_view<std::ranges::iota_view<int, int>, __lambda_10_33> > z = std::ranges::views::zip.operator()(i, sq, trip);
   x = std::size(i);
   y = std::size(sq);
  unsigned int u = std::size(z);
  std::println(std::basic_format_string<char, unsigned int &, unsigned int &, unsigned int &>("{} {} {}"), x, y, u);
  return 0;
}

Note that neither x nor y have a type in front of them, so the code is in fact invalid.