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@@ -1,550 +1,583 @@
 ## Header `<ranges>` synopsis <a id="ranges.syn">[[ranges.syn]]</a>
 ``` cpp
 #include <compare>              // see [compare.syn]
 #include <initializer_list>     // see [initializer.list.syn]
 #include <iterator>             // see [iterator.synopsis]
 namespace std::ranges {
   inline namespace unspecified {
     // [range.access], range access
-    inline constexpr unspecified begin = unspecified;                               // freestanding
-    inline constexpr unspecified end = unspecified;                                 // freestanding
-    inline constexpr unspecified cbegin = unspecified;                              // freestanding
-    inline constexpr unspecified cend = unspecified;                                // freestanding
-    inline constexpr unspecified rbegin = unspecified;                              // freestanding
-    inline constexpr unspecified rend = unspecified;                                // freestanding
-    inline constexpr unspecified crbegin = unspecified;                             // freestanding
-    inline constexpr unspecified crend = unspecified;                               // freestanding
-    inline constexpr unspecified size = unspecified;                                // freestanding
-    inline constexpr unspecified ssize = unspecified;                               // freestanding
-    inline constexpr unspecified empty = unspecified;                               // freestanding
-    inline constexpr unspecified data = unspecified;                                // freestanding
-    inline constexpr unspecified cdata = unspecified;                               // freestanding
   }
   // [range.range], ranges
   template<class T>
-    concept range = see below;                                                      // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range = false;                                   // freestanding
   template<class T>
-    concept borrowed_range = see below;                                             // freestanding
   template<class T>
-    using iterator_t = decltype(ranges::begin(declval<T&>()));                      // freestanding
   template<range R>
-    using sentinel_t = decltype(ranges::end(declval<R&>()));                        // freestanding
   template<range R>
-    using const_iterator_t = const_iterator<iterator_t<R>>;                         // freestanding
   template<range R>
-    using const_sentinel_t = const_sentinel<sentinel_t<R>>;                         // freestanding
   template<range R>
-    using range_difference_t = iter_difference_t<iterator_t<R>>;                    // freestanding
   template<sized_range R>
-    using range_size_t = decltype(ranges::size(declval<R&>()));                     // freestanding
   template<range R>
-    using range_value_t = iter_value_t<iterator_t<R>>;                              // freestanding
   template<range R>
-    using range_reference_t = iter_reference_t<iterator_t<R>>;                      // freestanding
   template<range R>
-    using range_const_reference_t = iter_const_reference_t<iterator_t<R>>;          // freestanding
   template<range R>
-    using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<R>>;        // freestanding
   template<range R>
-    using range_common_reference_t = iter_common_reference_t<iterator_t<R>>;        // freestanding
   // [range.sized], sized ranges
   template<class>
-    constexpr bool disable_sized_range = false;                                     // freestanding
   template<class T>
-    concept sized_range = see below;                                                // freestanding
   // [range.view], views
   template<class T>
-    constexpr bool enable_view = see below;                                         // freestanding
-  struct view_base {};                                                              // freestanding
   template<class T>
-    concept view = see below;                                                       // freestanding
   // [range.refinements], other range refinements
   template<class R, class T>
-    concept output_range = see below;                                               // freestanding
   template<class T>
-    concept input_range = see below;                                                // freestanding
   template<class T>
-    concept forward_range = see below;                                              // freestanding
   template<class T>
-    concept bidirectional_range = see below;                                        // freestanding
   template<class T>
-    concept random_access_range = see below;                                        // freestanding
   template<class T>
-    concept contiguous_range = see below;                                           // freestanding
   template<class T>
-    concept common_range = see below;                                               // freestanding
   template<class T>
-    concept viewable_range = see below;                                             // freestanding
   template<class T>
-    concept constant_range = see below;                                             // freestanding
   // [view.interface], class template view_interface
   template<class D>
     requires is_class_v<D> && same_as<D, remove_cv_t<D>>
-  class view_interface;                                                             // freestanding
   // [range.subrange], sub-ranges
-  enum class subrange_kind : bool { unsized, sized };                               // freestanding
   template<input_or_output_iterator I, sentinel_for<I> S = I, subrange_kind K = see below>
     requires (K == subrange_kind::sized || !sized_sentinel_for<S, I>)
-  class subrange;                                                                   // freestanding
   template<class I, class S, subrange_kind K>
-    constexpr bool enable_borrowed_range<subrange<I, S, K>> = true;                 // freestanding
   template<size_t N, class I, class S, subrange_kind K>
     requires ((N == 0 && copyable<I>) || N == 1)
-    constexpr auto get(const subrange<I, S, K>& r);                                 // freestanding
   template<size_t N, class I, class S, subrange_kind K>
     requires (N < 2)
-    constexpr auto get(subrange<I, S, K>&& r);                                      // freestanding
 }
 namespace std {
-  using ranges::get;                                                                // freestanding
 }
 namespace std::ranges {
   // [range.dangling], dangling iterator handling
-  struct dangling;                                                                  // freestanding
   // [range.elementsof], class template elements_of
   template<range R, class Allocator = allocator<byte>>
-    struct elements_of;
   template<range R>
-    using borrowed_iterator_t = see below;                                          // freestanding
   template<range R>
-    using borrowed_subrange_t = see below;                                          // freestanding
   // [range.utility.conv], range conversions
   template<class C, input_range R, class... Args> requires (!view<C>)
-    constexpr C to(R&& r, Args&&... args);                                          // freestanding
   template<template<class...> class C, input_range R, class... Args>
-    constexpr auto to(R&& r, Args&&... args);                                       // freestanding
   template<class C, class... Args> requires (!view<C>)
-    constexpr auto to(Args&&... args);                                              // freestanding
   template<template<class...> class C, class... Args>
-    constexpr auto to(Args&&... args);                                              // freestanding
   // [range.empty], empty view
   template<class T>
     requires is_object_v<T>
-  class empty_view;                                                                 // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<empty_view<T>> = true;                     // freestanding
   namespace views {
     template<class T>
-      constexpr empty_view<T> empty{};                                              // freestanding
   }
   // [range.single], single view
   template<move_constructible T>
     requires is_object_v<T>
-  class single_view;                                                                // freestanding
-  namespace views { inline constexpr unspecified single = unspecified; }            // freestanding
   template<bool Const, class T>
     using maybe-const = conditional_t<Const, const T, T>;   // exposition only
   // [range.iota], iota view
   template<weakly_incrementable W, semiregular Bound = unreachable_sentinel_t>
     requires weakly-equality-comparable-with<W, Bound> && copyable<W>
-  class iota_view;                                                                  // freestanding
   template<class W, class Bound>
-    constexpr bool enable_borrowed_range<iota_view<W, Bound>> = true;               // freestanding
-  namespace views { inline constexpr unspecified iota = unspecified; }              // freestanding
   // [range.repeat], repeat view
   template<move_constructible T, semiregular Bound = unreachable_sentinel_t>
     requires see below
-  class repeat_view;                                                                // freestanding
-  namespace views { inline constexpr unspecified repeat = unspecified; }            // freestanding
   // [range.istream], istream view
   template<movable Val, class CharT, class Traits = char_traits<CharT>>
     requires see below
-  class basic_istream_view;
   template<class Val>
-    using istream_view = basic_istream_view<Val, char>;
   template<class Val>
-    using wistream_view = basic_istream_view<Val, wchar_t>;
-  namespace views { template<class T> constexpr unspecified istream = unspecified; }
   // [range.adaptor.object], range adaptor objects
   template<class D>
     requires is_class_v<D> && same_as<D, remove_cv_t<D>>
-  class range_adaptor_closure { };                                                  // freestanding
   // [range.all], all view
   namespace views {
-    inline constexpr unspecified all = unspecified;                                 // freestanding
     template<viewable_range R>
-      using all_t = decltype(all(declval<R>()));                                    // freestanding
   }
   // [range.ref.view], ref view
   template<range R>
     requires is_object_v<R>
-  class ref_view;                                                                   // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<ref_view<T>> = true;                       // freestanding
   // [range.owning.view], owning view
   template<range R>
     requires see below
-  class owning_view;                                                                // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<owning_view<T>> =                          // freestanding
       enable_borrowed_range<T>;
   // [range.as.rvalue], as rvalue view
   template<view V>
     requires input_range<V>
-  class as_rvalue_view;                                                             // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<as_rvalue_view<T>> =                       // freestanding
       enable_borrowed_range<T>;
-  namespace views { inline constexpr unspecified as_rvalue = unspecified; }         // freestanding
   // [range.filter], filter view
   template<input_range V, indirect_unary_predicate<iterator_t<V>> Pred>
     requires view<V> && is_object_v<Pred>
-  class filter_view;                                                                // freestanding
-  namespace views { inline constexpr unspecified filter = unspecified; }            // freestanding
   // [range.transform], transform view
   template<input_range V, move_constructible F>
     requires view<V> && is_object_v<F> &&
              regular_invocable<F&, range_reference_t<V>> &&
              can-reference<invoke_result_t<F&, range_reference_t<V>>>
-  class transform_view;                                                             // freestanding
-  namespace views { inline constexpr unspecified transform = unspecified; }         // freestanding
   // [range.take], take view
-  template<view> class take_view;                                                   // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<take_view<T>> =                            // freestanding
       enable_borrowed_range<T>;
-  namespace views { inline constexpr unspecified take = unspecified; }              // freestanding
   // [range.take.while], take while view
   template<view V, class Pred>
     requires input_range<V> && is_object_v<Pred> &&
              indirect_unary_predicate<const Pred, iterator_t<V>>
-    class take_while_view;                                                          // freestanding
-  namespace views { inline constexpr unspecified take_while = unspecified; }        // freestanding
   // [range.drop], drop view
   template<view V>
-    class drop_view;                                                                // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<drop_view<T>> =                            // freestanding
       enable_borrowed_range<T>;
-  namespace views { inline constexpr unspecified drop = unspecified; }              // freestanding
   // [range.drop.while], drop while view
   template<view V, class Pred>
     requires input_range<V> && is_object_v<Pred> &&
              indirect_unary_predicate<const Pred, iterator_t<V>>
-    class drop_while_view;                                                          // freestanding
   template<class T, class Pred>
-    constexpr bool enable_borrowed_range<drop_while_view<T, Pred>> =                // freestanding
       enable_borrowed_range<T>;
-  namespace views { inline constexpr unspecified drop_while = unspecified; }        // freestanding
   // [range.join], join view
   template<input_range V>
     requires view<V> && input_range<range_reference_t<V>>
-  class join_view;                                                                  // freestanding
-  namespace views { inline constexpr unspecified join = unspecified; }              // freestanding
   // [range.join.with], join with view
-  template<class R, class P>
-    concept compatible-joinable-ranges = see below; // exposition only
   template<input_range V, forward_range Pattern>
-    requires view<V> && input_range<range_reference_t<V>>
-          && view<Pattern>
-          && compatible-joinable-ranges<range_reference_t<V>, Pattern>
-  class join_with_view;                                                             // freestanding
-  namespace views { inline constexpr unspecified join_with = unspecified; }         // freestanding
   // [range.lazy.split], lazy split view
   template<class R>
     concept tiny-range = see below;   // exposition only
   template<input_range V, forward_range Pattern>
     requires view<V> && view<Pattern> &&
              indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to> &&
              (forward_range<V> || tiny-range<Pattern>)
-  class lazy_split_view;                                                            // freestanding
   // [range.split], split view
   template<forward_range V, forward_range Pattern>
     requires view<V> && view<Pattern> &&
              indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to>
-  class split_view;                                                                 // freestanding
   namespace views {
-    inline constexpr unspecified lazy_split = unspecified;                          // freestanding
-    inline constexpr unspecified split = unspecified;                               // freestanding
   }
   // [range.counted], counted view
-  namespace views { inline constexpr unspecified counted = unspecified; }           // freestanding
   // [range.common], common view
   template<view V>
     requires (!common_range<V> && copyable<iterator_t<V>>)
-  class common_view;                                                                // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<common_view<T>> =                          // freestanding
       enable_borrowed_range<T>;
-  namespace views { inline constexpr unspecified common = unspecified; }            // freestanding
   // [range.reverse], reverse view
   template<view V>
     requires bidirectional_range<V>
-  class reverse_view;                                                               // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<reverse_view<T>> =                         // freestanding
       enable_borrowed_range<T>;
-  namespace views { inline constexpr unspecified reverse = unspecified; }           // freestanding
   // [range.as.const], as const view
   template<input_range R>
-    constexpr auto& possibly-const-range(R& r) { // exposition only
-      if constexpr (constant_range<const R> && !constant_range<R>) {
         return const_cast<const R&>(r);
       } else {
         return r;
       }
     }
   template<view V>
     requires input_range<V>
-  class as_const_view;                                                              // freestanding
   template<class T>
-    constexpr bool enable_borrowed_range<as_const_view<T>> =                        // freestanding
       enable_borrowed_range<T>;
-  namespace views { inline constexpr unspecified as_const = unspecified; }          // freestanding
   // [range.elements], elements view
   template<input_range V, size_t N>
     requires see below
-  class elements_view;                                                              // freestanding
   template<class T, size_t N>
-    constexpr bool enable_borrowed_range<elements_view<T, N>> =                     // freestanding
       enable_borrowed_range<T>;
   template<class R>
-    using keys_view = elements_view<R, 0>;                                          // freestanding
   template<class R>
-    using values_view = elements_view<R, 1>;                                        // freestanding
   namespace views {
     template<size_t N>
-      constexpr unspecified elements = unspecified;                                 // freestanding
-    inline constexpr auto keys = elements<0>;                                       // freestanding
-    inline constexpr auto values = elements<1>;                                     // freestanding
   }
   // [range.enumerate], enumerate view
-  template<input_range View>
-    requires view<View>
-  class enumerate_view;                                                             // freestanding
   template<class View>
-    constexpr bool enable_borrowed_range<enumerate_view<View>> =                    // freestanding
       enable_borrowed_range<View>;
-  namespace views { inline constexpr unspecified enumerate = unspecified; }         // freestanding
   // [range.zip], zip view
   template<input_range... Views>
     requires (view<Views> && ...) && (sizeof...(Views) > 0)
-  class zip_view;                                                                   // freestanding
   template<class... Views>
-    constexpr bool enable_borrowed_range<zip_view<Views...>> =                      // freestanding
       (enable_borrowed_range<Views> && ...);
-  namespace views { inline constexpr unspecified zip = unspecified; }               // freestanding
   // [range.zip.transform], zip transform view
   template<move_constructible F, input_range... Views>
     requires (view<Views> && ...) && (sizeof...(Views) > 0) && is_object_v<F> &&
              regular_invocable<F&, range_reference_t<Views>...> &&
              can-reference<invoke_result_t<F&, range_reference_t<Views>...>>
-  class zip_transform_view;                                                         // freestanding
-  namespace views { inline constexpr unspecified zip_transform = unspecified; }     // freestanding
   // [range.adjacent], adjacent view
   template<forward_range V, size_t N>
     requires view<V> && (N > 0)
-  class adjacent_view;                                                              // freestanding
   template<class V, size_t N>
-    constexpr bool enable_borrowed_range<adjacent_view<V, N>> =                     // freestanding
       enable_borrowed_range<V>;
   namespace views {
     template<size_t N>
-      constexpr unspecified adjacent = unspecified;                                 // freestanding
-    inline constexpr auto pairwise = adjacent<2>;                                   // freestanding
   }
   // [range.adjacent.transform], adjacent transform view
   template<forward_range V, move_constructible F, size_t N>
     requires see below
-  class adjacent_transform_view;                                                    // freestanding
   namespace views {
     template<size_t N>
-      constexpr unspecified adjacent_transform = unspecified;                       // freestanding
-    inline constexpr auto pairwise_transform = adjacent_transform<2>;               // freestanding
   }
   // [range.chunk], chunk view
   template<view V>
     requires input_range<V>
-  class chunk_view;                                                                 // freestanding
   template<view V>
     requires forward_range<V>
-  class chunk_view<V>;                                                              // freestanding
   template<class V>
-    constexpr bool enable_borrowed_range<chunk_view<V>> =                           // freestanding
       forward_range<V> && enable_borrowed_range<V>;
-  namespace views { inline constexpr unspecified chunk = unspecified; }             // freestanding
   // [range.slide], slide view
   template<forward_range V>
     requires view<V>
-  class slide_view;                                                                 // freestanding
   template<class V>
-    constexpr bool enable_borrowed_range<slide_view<V>> =
-      enable_borrowed_range<V>;                                                     // freestanding
-  namespace views { inline constexpr unspecified slide = unspecified; }             // freestanding
   // [range.chunk.by], chunk by view
   template<forward_range V, indirect_binary_predicate<iterator_t<V>, iterator_t<V>> Pred>
     requires view<V> && is_object_v<Pred>
-  class chunk_by_view;                                                              // freestanding
-  namespace views { inline constexpr unspecified chunk_by = unspecified; }          // freestanding
   // [range.stride], stride view
   template<input_range V>
     requires view<V>
-  class stride_view;                                                                // freestanding
   template<class V>
-    constexpr bool enable_borrowed_range<stride_view<V>> =                          // freestanding
       enable_borrowed_range<V>;
-  namespace views { inline constexpr unspecified stride = unspecified; }            // freestanding
   // [range.cartesian], cartesian product view
   template<input_range First, forward_range... Vs>
     requires (view<First> && ... && view<Vs>)
-  class cartesian_product_view;                                                     // freestanding
-  namespace views { inline constexpr unspecified cartesian_product = unspecified; } // freestanding
 }
 namespace std {
-  namespace views = ranges::views;                                                  // freestanding
-  template<class T> struct tuple_size;                                              // freestanding
-  template<size_t I, class T> struct tuple_element;                                 // freestanding
   template<class I, class S, ranges::subrange_kind K>
-  struct tuple_size<ranges::subrange<I, S, K>>                                      // freestanding
     : integral_constant<size_t, 2> {};
   template<class I, class S, ranges::subrange_kind K>
-  struct tuple_element<0, ranges::subrange<I, S, K>> {                              // freestanding
-    using type = I;                                                                 // freestanding
   };
   template<class I, class S, ranges::subrange_kind K>
-  struct tuple_element<1, ranges::subrange<I, S, K>> {                              // freestanding
-    using type = S;                                                                 // freestanding
   };
   template<class I, class S, ranges::subrange_kind K>
-  struct tuple_element<0, const ranges::subrange<I, S, K>> {                        // freestanding
-    using type = I;                                                                 // freestanding
   };
   template<class I, class S, ranges::subrange_kind K>
-  struct tuple_element<1, const ranges::subrange<I, S, K>> {                        // freestanding
-    using type = S;                                                                 // freestanding
   };
-  struct from_range_t { explicit from_range_t() = default; };                       // freestanding
-  inline constexpr from_range_t from_range{};                                       // freestanding
 }
 ```
 Within this Clause, for an integer-like type `X`
 [[iterator.concept.winc]], `make-unsigned-like-t<X>` denotes

 ## Header `<ranges>` synopsis <a id="ranges.syn">[[ranges.syn]]</a>
 ``` cpp
+// mostly freestanding
 #include <compare>              // see [compare.syn]
 #include <initializer_list>     // see [initializer.list.syn]
 #include <iterator>             // see [iterator.synopsis]
 namespace std::ranges {
   inline namespace unspecified {
     // [range.access], range access
+    inline constexpr unspecified begin = unspecified;
+    inline constexpr unspecified end = unspecified;
+    inline constexpr unspecified cbegin = unspecified;
+    inline constexpr unspecified cend = unspecified;
+    inline constexpr unspecified rbegin = unspecified;
+    inline constexpr unspecified rend = unspecified;
+    inline constexpr unspecified crbegin = unspecified;
+    inline constexpr unspecified crend = unspecified;
+    inline constexpr unspecified size = unspecified;
+    inline constexpr unspecified reserve_hint = unspecified;
+    inline constexpr unspecified ssize = unspecified;
+    inline constexpr unspecified empty = unspecified;
+    inline constexpr unspecified data = unspecified;
+    inline constexpr unspecified cdata = unspecified;
   }
   // [range.range], ranges
   template<class T>
+    concept range = see below;
   template<class T>
+    constexpr bool enable_borrowed_range = false;
   template<class T>
+    concept borrowed_range = see below;
   template<class T>
+    using iterator_t = decltype(ranges::begin(declval<T&>()));
   template<range R>
+    using sentinel_t = decltype(ranges::end(declval<R&>()));
   template<range R>
+    using const_iterator_t = decltype(ranges::cbegin(declval<R&>()));
   template<range R>
+    using const_sentinel_t = decltype(ranges::cend(declval<R&>()));
   template<range R>
+    using range_difference_t = iter_difference_t<iterator_t<R>>;
   template<sized_range R>
+    using range_size_t = decltype(ranges::size(declval<R&>()));
   template<range R>
+    using range_value_t = iter_value_t<iterator_t<R>>;
   template<range R>
+    using range_reference_t = iter_reference_t<iterator_t<R>>;
   template<range R>
+    using range_const_reference_t = iter_const_reference_t<iterator_t<R>>;
   template<range R>
+    using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<R>>;
   template<range R>
+    using range_common_reference_t = iter_common_reference_t<iterator_t<R>>;
   // [range.sized], sized ranges
   template<class>
+    constexpr bool disable_sized_range = false;
   template<class T>
+    concept approximately_sized_range = see below;
+  template<class T>
+    concept sized_range = see below;
   // [range.view], views
   template<class T>
+    constexpr bool enable_view = see below;
+  struct view_base {};
   template<class T>
+    concept view = see below;
   // [range.refinements], other range refinements
   template<class R, class T>
+    concept output_range = see below;
   template<class T>
+    concept input_range = see below;
   template<class T>
+    concept forward_range = see below;
   template<class T>
+    concept bidirectional_range = see below;
   template<class T>
+    concept random_access_range = see below;
   template<class T>
+    concept contiguous_range = see below;
   template<class T>
+    concept common_range = see below;
   template<class T>
+    concept viewable_range = see below;
   template<class T>
+    concept constant_range = see below;
+  template<class T>
+    concept sized-random-access-range = see belownc;              // exposition only
   // [view.interface], class template view_interface
   template<class D>
     requires is_class_v<D> && same_as<D, remove_cv_t<D>>
+  class view_interface;
   // [range.subrange], sub-ranges
+  enum class subrange_kind : bool { unsized, sized };
   template<input_or_output_iterator I, sentinel_for<I> S = I, subrange_kind K = see below>
     requires (K == subrange_kind::sized || !sized_sentinel_for<S, I>)
+  class subrange;
   template<class I, class S, subrange_kind K>
+    constexpr bool \libspec{enable_borrowed_range}{subrange}<subrange<I, S, K>> = true;
   template<size_t N, class I, class S, subrange_kind K>
     requires ((N == 0 && copyable<I>) || N == 1)
+    constexpr auto get(const subrange<I, S, K>& r);
   template<size_t N, class I, class S, subrange_kind K>
     requires (N < 2)
+    constexpr auto get(subrange<I, S, K>&& r);
 }
 namespace std {
+  using ranges::get;
 }
 namespace std::ranges {
   // [range.dangling], dangling iterator handling
+  struct dangling;
   // [range.elementsof], class template elements_of
   template<range R, class Allocator = allocator<byte>>
+    struct elements_of;                                                             // hosted
   template<range R>
+    using borrowed_iterator_t = see below;
   template<range R>
+    using borrowed_subrange_t = see below;
   // [range.utility.conv], range conversions
   template<class C, input_range R, class... Args> requires (!view<C>)
+    constexpr C to(R&& r, Args&&... args);
   template<template<class...> class C, input_range R, class... Args>
+    constexpr auto to(R&& r, Args&&... args);
   template<class C, class... Args> requires (!view<C>)
+    constexpr auto to(Args&&... args);
   template<template<class...> class C, class... Args>
+    constexpr auto to(Args&&... args);
   // [range.empty], empty view
   template<class T>
     requires is_object_v<T>
+  class empty_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{empty_view}<empty_view<T>> = true;
   namespace views {
     template<class T>
+      constexpr empty_view<T> empty{};
   }
   // [range.single], single view
   template<move_constructible T>
     requires is_object_v<T>
+  class single_view;
+  namespace views { inline constexpr unspecified single = unspecified; }
   template<bool Const, class T>
     using maybe-const = conditional_t<Const, const T, T>;   // exposition only
   // [range.iota], iota view
   template<weakly_incrementable W, semiregular Bound = unreachable_sentinel_t>
     requires weakly-equality-comparable-with<W, Bound> && copyable<W>
+  class iota_view;
   template<class W, class Bound>
+    constexpr bool \libspec{enable_borrowed_range}{iota_view}<iota_view<W, Bound>> = true;
+  namespace views {
+    inline constexpr unspecified iota = unspecified;
+    inline constexpr unspecified indices = unspecified;
+  }
   // [range.repeat], repeat view
   template<move_constructible T, semiregular Bound = unreachable_sentinel_t>
     requires see below
+  class repeat_view;
+  namespace views { inline constexpr unspecified repeat = unspecified; }
   // [range.istream], istream view
   template<movable Val, class CharT, class Traits = char_traits<CharT>>
     requires see below
+  class basic_istream_view;                                                         // hosted
   template<class Val>
+    using istream_view = basic_istream_view<Val, char>;                             // hosted
   template<class Val>
+    using wistream_view = basic_istream_view<Val, wchar_t>;                         // hosted
+  namespace views {
+    template<class T> constexpr unspecified istream = unspecified;                  // hosted
+  }
   // [range.adaptor.object], range adaptor objects
   template<class D>
     requires is_class_v<D> && same_as<D, remove_cv_t<D>>
+  class range_adaptor_closure { };
   // [range.all], all view
   namespace views {
+    inline constexpr unspecified all = unspecified;
     template<viewable_range R>
+      using all_t = decltype(all(declval<R>()));
   }
   // [range.ref.view], ref view
   template<range R>
     requires is_object_v<R>
+  class ref_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{ref_view}<ref_view<T>> = true;
   // [range.owning.view], owning view
   template<range R>
     requires see below
+  class owning_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{owning_view}<owning_view<T>> =
       enable_borrowed_range<T>;
   // [range.as.rvalue], as rvalue view
   template<view V>
     requires input_range<V>
+  class as_rvalue_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{as_rvalue_view}<as_rvalue_view<T>> =
       enable_borrowed_range<T>;
+  namespace views { inline constexpr unspecified as_rvalue = unspecified; }
   // [range.filter], filter view
   template<input_range V, indirect_unary_predicate<iterator_t<V>> Pred>
     requires view<V> && is_object_v<Pred>
+  class filter_view;
+  namespace views { inline constexpr unspecified filter = unspecified; }
   // [range.transform], transform view
   template<input_range V, move_constructible F>
     requires view<V> && is_object_v<F> &&
              regular_invocable<F&, range_reference_t<V>> &&
              can-reference<invoke_result_t<F&, range_reference_t<V>>>
+  class transform_view;
+  namespace views { inline constexpr unspecified transform = unspecified; }
   // [range.take], take view
+  template<view> class take_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{take_view}<take_view<T>> =
       enable_borrowed_range<T>;
+  namespace views { inline constexpr unspecified take = unspecified; }
   // [range.take.while], take while view
   template<view V, class Pred>
     requires input_range<V> && is_object_v<Pred> &&
              indirect_unary_predicate<const Pred, iterator_t<V>>
+    class take_while_view;
+  namespace views { inline constexpr unspecified take_while = unspecified; }
   // [range.drop], drop view
   template<view V>
+    class drop_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{drop_view}<drop_view<T>> =
       enable_borrowed_range<T>;
+  namespace views { inline constexpr unspecified drop = unspecified; }
   // [range.drop.while], drop while view
   template<view V, class Pred>
     requires input_range<V> && is_object_v<Pred> &&
              indirect_unary_predicate<const Pred, iterator_t<V>>
+    class drop_while_view;
   template<class T, class Pred>
+    constexpr bool \libspec{enable_borrowed_range}{drop_while_view}<drop_while_view<T, Pred>> =
       enable_borrowed_range<T>;
+  namespace views { inline constexpr unspecified drop_while = unspecified; }
   // [range.join], join view
   template<input_range V>
     requires view<V> && input_range<range_reference_t<V>>
+  class join_view;
+  namespace views { inline constexpr unspecified join = unspecified; }
   // [range.join.with], join with view
   template<input_range V, forward_range Pattern>
+    requires see below
+  class join_with_view;
+  namespace views { inline constexpr unspecified join_with = unspecified; }
   // [range.lazy.split], lazy split view
   template<class R>
     concept tiny-range = see below;   // exposition only
   template<input_range V, forward_range Pattern>
     requires view<V> && view<Pattern> &&
              indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to> &&
              (forward_range<V> || tiny-range<Pattern>)
+  class lazy_split_view;
   // [range.split], split view
   template<forward_range V, forward_range Pattern>
     requires view<V> && view<Pattern> &&
              indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to>
+  class split_view;
   namespace views {
+    inline constexpr unspecified lazy_split = unspecified;
+    inline constexpr unspecified split = unspecified;
   }
+  // [range.concat], concat view
+  template<input_range... Views>
+    requires see below
+  class concat_view;
+  namespace views { inline constexpr unspecified concat = unspecified; }
   // [range.counted], counted view
+  namespace views { inline constexpr unspecified counted = unspecified; }
   // [range.common], common view
   template<view V>
     requires (!common_range<V> && copyable<iterator_t<V>>)
+  class common_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{common_view}<common_view<T>> =
       enable_borrowed_range<T>;
+  namespace views { inline constexpr unspecified common = unspecified; }
   // [range.reverse], reverse view
   template<view V>
     requires bidirectional_range<V>
+  class reverse_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{reverse_view}<reverse_view<T>> =
       enable_borrowed_range<T>;
+  namespace views { inline constexpr unspecified reverse = unspecified; }
   // [range.as.const], as const view
   template<input_range R>
+    constexpr auto& possibly-const-range(R& r) noexcept { // exposition only
+      if constexpr (input_range<const R>) {
         return const_cast<const R&>(r);
       } else {
         return r;
       }
     }
   template<view V>
     requires input_range<V>
+  class as_const_view;
   template<class T>
+    constexpr bool \libspec{enable_borrowed_range}{as_const_view}<as_const_view<T>> =
       enable_borrowed_range<T>;
+  namespace views { inline constexpr unspecified as_const = unspecified; }
   // [range.elements], elements view
   template<input_range V, size_t N>
     requires see below
+  class elements_view;
   template<class T, size_t N>
+    constexpr bool \libspec{enable_borrowed_range}{elements_view}<elements_view<T, N>> =
       enable_borrowed_range<T>;
   template<class R>
+    using keys_view = elements_view<R, 0>;
   template<class R>
+    using values_view = elements_view<R, 1>;
   namespace views {
     template<size_t N>
+      constexpr unspecified elements = unspecified;
+    inline constexpr auto keys = elements<0>;
+    inline constexpr auto values = elements<1>;
   }
   // [range.enumerate], enumerate view
+  template<view V>
+    requires see below
+  class enumerate_view;
   template<class View>
+    constexpr bool \libspec{enable_borrowed_range}{enumerate_view}<enumerate_view<View>> =
       enable_borrowed_range<View>;
+  namespace views { inline constexpr unspecified enumerate = unspecified; }
   // [range.zip], zip view
   template<input_range... Views>
     requires (view<Views> && ...) && (sizeof...(Views) > 0)
+  class zip_view;
   template<class... Views>
+    constexpr bool \libspec{enable_borrowed_range}{zip_view}<zip_view<Views...>> =
       (enable_borrowed_range<Views> && ...);
+  namespace views { inline constexpr unspecified zip = unspecified; }
   // [range.zip.transform], zip transform view
   template<move_constructible F, input_range... Views>
     requires (view<Views> && ...) && (sizeof...(Views) > 0) && is_object_v<F> &&
              regular_invocable<F&, range_reference_t<Views>...> &&
              can-reference<invoke_result_t<F&, range_reference_t<Views>...>>
+  class zip_transform_view;
+  namespace views { inline constexpr unspecified zip_transform = unspecified; }
   // [range.adjacent], adjacent view
   template<forward_range V, size_t N>
     requires view<V> && (N > 0)
+  class adjacent_view;
   template<class V, size_t N>
+    constexpr bool \libspec{enable_borrowed_range}{adjacent_view}<adjacent_view<V, N>> =
       enable_borrowed_range<V>;
   namespace views {
     template<size_t N>
+      constexpr unspecified adjacent = unspecified;
+    inline constexpr auto pairwise = adjacent<2>;
   }
   // [range.adjacent.transform], adjacent transform view
   template<forward_range V, move_constructible F, size_t N>
     requires see below
+  class adjacent_transform_view;
   namespace views {
     template<size_t N>
+      constexpr unspecified adjacent_transform = unspecified;
+    inline constexpr auto pairwise_transform = adjacent_transform<2>;
   }
   // [range.chunk], chunk view
   template<view V>
     requires input_range<V>
+  class chunk_view;
   template<view V>
     requires forward_range<V>
+  class chunk_view<V>;
   template<class V>
+    constexpr bool \libspec{enable_borrowed_range}{chunk_view}<chunk_view<V>> =
       forward_range<V> && enable_borrowed_range<V>;
+  namespace views { inline constexpr unspecified chunk = unspecified; }
   // [range.slide], slide view
   template<forward_range V>
     requires view<V>
+  class slide_view;
   template<class V>
+    constexpr bool \libspec{enable_borrowed_range}{slide_view}<slide_view<V>> =
+      enable_borrowed_range<V>;
+  namespace views { inline constexpr unspecified slide = unspecified; }
   // [range.chunk.by], chunk by view
   template<forward_range V, indirect_binary_predicate<iterator_t<V>, iterator_t<V>> Pred>
     requires view<V> && is_object_v<Pred>
+  class chunk_by_view;
+  namespace views { inline constexpr unspecified chunk_by = unspecified; }
   // [range.stride], stride view
   template<input_range V>
     requires view<V>
+  class stride_view;
   template<class V>
+    constexpr bool \libspec{enable_borrowed_range}{stride_view}<stride_view<V>> =
       enable_borrowed_range<V>;
+  namespace views { inline constexpr unspecified stride = unspecified; }
   // [range.cartesian], cartesian product view
   template<input_range First, forward_range... Vs>
     requires (view<First> && ... && view<Vs>)
+  class cartesian_product_view;
+  namespace views { inline constexpr unspecified cartesian_product = unspecified; }
+  // [range.cache.latest], cache latest view
+  template<input_range V>
+    requires view<V>
+  class cache_latest_view;
+  namespace views { inline constexpr unspecified cache_latest = unspecified; }
+  // [range.to.input], to input view
+  template<input_range V>
+    requires view<V>
+  class to_input_view;
+  template<class V>
+    constexpr bool enable_borrowed_range<to_input_view<V>> =
+      enable_borrowed_range<V>;
+  namespace views { inline constexpr unspecified to_input = unspecified; }
 }
 namespace std {
+  namespace views = ranges::views;
+  template<class T> struct tuple_size;
+  template<size_t I, class T> struct tuple_element;
   template<class I, class S, ranges::subrange_kind K>
+  struct tuple_size<ranges::subrange<I, S, K>>
     : integral_constant<size_t, 2> {};
   template<class I, class S, ranges::subrange_kind K>
+  struct tuple_element<0, ranges::subrange<I, S, K>> {
+    using type = I;
   };
   template<class I, class S, ranges::subrange_kind K>
+  struct tuple_element<1, ranges::subrange<I, S, K>> {
+    using type = S;
   };
   template<class I, class S, ranges::subrange_kind K>
+  struct tuple_element<0, const ranges::subrange<I, S, K>> {
+    using type = I;
   };
   template<class I, class S, ranges::subrange_kind K>
+  struct tuple_element<1, const ranges::subrange<I, S, K>> {
+    using type = S;
   };
+  struct from_range_t { explicit from_range_t() = default; };
+  inline constexpr from_range_t from_range{};
 }
 ```
 Within this Clause, for an integer-like type `X`
 [[iterator.concept.winc]], `make-unsigned-like-t<X>` denotes

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