Fix & Update <ranges>

README.md

@@ -358,37 +358,38 @@ Description
 
 * `<concepts>`
 
-  |                         | Introduced | Revision |
-  |-------------------------|------------|----------|
-  | `same_as`               | ![][c20ok] |          |
-  | `derived_from`          | ![][c20ok] |          |
-  | `convertible_to`        | ![][c20ok] |          |
-  | `common_reference_with` | ![][c20ok] |          |
-  | `common_with`           | ![][c20ok] |          |
-  | `integral`              | ![][c20ok] |          |
-  | `signed_integral`       | ![][c20ok] |          |
-  | `unsigned_integral`     | ![][c20ok] |          |
-  | `floating_point`        | ![][c20ok] |          |
-  | `assignable_from`       | ![][c20ok] |          |
-  | `swappable`             | ![][c20ok] |          |
-  | `destructible`          | ![][c20ok] |          |
-  | `constructible_from`    | ![][c20ok] |          |
-  | `default_initializable` | ![][c20ok] |          |
-  | `move_constructible`    | ![][c20ok] |          |
-  | `copy_constructible`    | ![][c20ok] |          |
-  | `equality_comparable`   | ![][c20ok] |          |
-  | `totally_ordered`       | ![][c20ok] |          |
-  | `movable`               | ![][c20ok] |          |
-  | `copyable`              | ![][c20ok] |          |
-  | `semiregular`           | ![][c20ok] |          |
-  | `regular`               | ![][c20ok] |          |
-  | `invocable`             | ![][c20ok] |          |
-  | `regular_invocable`     | ![][c20ok] |          |
-  | `predicate`             | ![][c20ok] |          |
-  | `relation`              | ![][c20ok] |          |
-  | `equivalence_relation`  | ![][c20ok] |          |
-  | `strict_weak_order`     | ![][c20ok] |          |
-  | `ranges::swap`          | ![][c20ok] |          |
+  |                            | Introduced | Revision   |
+  |----------------------------|------------|------------|
+  | `same_as`                  | ![][c20ok] |            |
+  | `derived_from`             | ![][c20ok] |            |
+  | `convertible_to`           | ![][c20ok] |            |
+  | `common_reference_with`    | ![][c20ok] |            |
+  | `common_with`              | ![][c20ok] |            |
+  | `integral`                 | ![][c20ok] |            |
+  | `signed_integral`          | ![][c20ok] |            |
+  | `unsigned_integral`        | ![][c20ok] |            |
+  | `floating_point`           | ![][c20ok] |            |
+  | `assignable_from`          | ![][c20ok] |            |
+  | `swappable`                | ![][c20ok] |            |
+  | `destructible`             | ![][c20ok] |            |
+  | `constructible_from`       | ![][c20ok] |            |
+  | `default_initializable`    | ![][c20ok] |            |
+  | `move_constructible`       | ![][c20ok] |            |
+  | `copy_constructible`       | ![][c20ok] |            |
+  | `equality_comparable`      | ![][c20ok] |            |
+  | `equality_comparable_with` | ![][c20ok] | ![][c23ok] |
+  | `totally_ordered`          | ![][c20ok] |            |
+  | `movable`                  | ![][c20ok] |            |
+  | `copyable`                 | ![][c20ok] |            |
+  | `semiregular`              | ![][c20ok] |            |
+  | `regular`                  | ![][c20ok] |            |
+  | `invocable`                | ![][c20ok] |            |
+  | `regular_invocable`        | ![][c20ok] |            |
+  | `predicate`                | ![][c20ok] |            |
+  | `relation`                 | ![][c20ok] |            |
+  | `equivalence_relation`     | ![][c20ok] |            |
+  | `strict_weak_order`        | ![][c20ok] |            |
+  | `ranges::swap`             | ![][c20ok] |            |
 
 * `<coroutine>` N/A
 
@@ -660,7 +661,7 @@ Description
   | `ranges::contiguous_range`                                        | ![][c20ok]           |            |
   | `ranges::common_range`                                            | ![][c20ok]           |            |
   | `ranges::viewable_range`                                          | ![][c20ok]           |            |
-  | `ranges::constant_range`                                          | ![][c20ok]           |            |
+  | `ranges::constant_range`                                          | ![][c23ok]           |            |
   | `ranges::to`                                                      | ![][c23ok] (Partial) |            |
   | `ranges::iterator_t`                                              | ![][c20ok]           |            |
   | `ranges::const_iterator_t`                                        | ![][c23ok]           |            |
@@ -670,11 +671,11 @@ Description
   | `ranges::range_size_t`                                            | ![][c20ok]           |            |
   | `ranges::range_value_t`                                           | ![][c20ok]           |            |
   | `ranges::range_refernce_t`                                        | ![][c20ok]           |            |
-  | `ranges::range_const_reference_t`                                 | ![][c20ok]           |            |
+  | `ranges::range_const_reference_t`                                 | ![][c23ok]           |            |
   | `ranges::range_rvalue_reference_t`                                | ![][c20ok]           |            |
   | `ranges::range_common_reference_t`                                | ![][c20ok]           |            |
-  | `ranges::view_interface`                                          | ![][c20ok]           |            |
-  | `ranges::subrange`                                                | ![][c20ok]           |            |
+  | `ranges::view_interface`                                          | ![][c20ok]           | ![][c23ok] |
+  | `ranges::subrange`                                                | ![][c20ok]           | ![][c23ok] |
   | `ranges::dangling`                                                | ![][c20ok]           |            |
   | `ranges::borrowed_iterator_t`                                     | ![][c20ok]           |            |
   | `ranges::borrowed_subrange_t`                                     | ![][c20ok]           |            |
@@ -690,13 +691,13 @@ Description
   | `ranges::ref_view`                                                | ![][c20ok]           |            |
   | `ranges::owning_view`                                             | ![][c20ok]           |            |
   | `ranges::filter_view`<br/>`views::filter`                         | ![][c20ok]           |            |
-  | `ranges::transform_view`<br/>`views::transform`                   | ![][c20ok]           |            |
+  | `ranges::transform_view`<br/>`views::transform`                   | ![][c20ok]           | ![][c23ok] |
   | `ranges::take_view`<br/>`views::take`                             | ![][c20ok]           |            |
   | `ranges::take_while_view`<br/>`views::take_while`                 | ![][c20ok]           |            |
-  | `ranges::drop_view`<br/>`views::drop`                             | ![][c20ok]           |            |
+  | `ranges::drop_view`<br/>`views::drop`                             | ![][c20ok]           | ![][c23ok] |
   | `ranges::drop_while_view`<br/>`views::drop_while`                 | ![][c20ok]           |            |
   | `ranges::join_view`<br/>`views::join`                             | ![][c20ok]           |            |
-  | `ranges::lazy_split_view`<br/>`views::lazy_split`                 | ![][c20ok]           |            |
+  | `ranges::lazy_split_view`<br/>`views::lazy_split`                 | ![][c20no]           |            |
   | `ranges::split_view`<br/>`views::split`                           | ![][c20ok]           |            |
   | `views::counted`                                                  | ![][c20ok]           |            |
   | `ranges::common_view`<br/>`views::common`                         | ![][c20ok]           |            |

include/preview/__functional/bind_back.h

@@ -51,7 +51,7 @@ template<typename F, typename... Args, std::enable_if_t<conjunction<
     std::is_move_constructible<std::decay_t<Args>>...
 >::value, int> = 0>
 constexpr auto bind_back(F&& f, Args&&... args) {
-  return detail::bind_back_object<std::decay_t<F>, std::decay_t<Args>...>{
+  return detail::bind_back_object<std::decay_t<F>, Args&&...>{
       detail::bind_object_ctor_tag{},
       std::forward<F>(f),
       std::forward<Args>(args)...

include/preview/__functional/bind_front.h

@@ -49,7 +49,7 @@ template<typename F, typename... Args, std::enable_if_t<conjunction<
     std::is_move_constructible<std::decay_t<Args>>...
 >::value, int> = 0>
 constexpr auto bind_front(F&& f, Args&&... args) {
-  return detail::bind_front_object<std::decay_t<F>, std::decay_t<Args>...>{
+  return detail::bind_front_object<std::decay_t<F>, Args&&...>{
     detail::bind_object_ctor_tag{},
     std::forward<F>(f),
     std::forward<Args>(args)...

include/preview/__functional/detail/bind_base.h

@@ -32,7 +32,6 @@ class bind_object_base {
   constexpr typename bind_invoke_result<Derived&, U&&...>::type
   operator()(U&&... args) & noexcept(bind_nothrow_invocable<Derived&, U&&...>::value) {
     return call(*this, std::forward<U>(args)...);
-    return Derived::call(derived(), index_sequence{}, std::forward<U>(args)...);
   }
 
   template<typename... U>

include/preview/__iterator/contiguous_iterator.h

@@ -10,6 +10,7 @@
 #include "preview/__concepts/derived_from.h"
 #include "preview/__concepts/same_as.h"
 #include "preview/__concepts/requires_expression.h"
+#include "preview/__iterator/detail/have_cxx20_iterator.h"
 #include "preview/__iterator/detail/iter_concept.h"
 #include "preview/__iterator/iterator_traits/legacy_random_access_iterator.h"
 #include "preview/__iterator/iter_reference_t.h"
@@ -48,11 +49,11 @@ struct contiguous_iterator_impl : std::false_type {};
 template<typename I>
 struct contiguous_iterator_impl<I, true>
     : conjunction<
-#if __cplusplus < 202002L
+#if !PREVIEW_STD_HAVE_CXX20_ITERATOR
         disjunction<
 #endif
             derived_from<ITER_CONCEPT<I>, contiguous_iterator_tag>,
-#if __cplusplus < 202002L
+#if !PREVIEW_STD_HAVE_CXX20_ITERATOR
             conjunction<
               derived_from<ITER_CONCEPT<I>, random_access_iterator_tag>,
               LegacyRandomAccessIterator<I>

include/preview/__ranges/owning_view.h

@@ -105,13 +105,6 @@ class owning_view : public view_interface<owning_view<R>> {
   R r_;
 };
 
-#if __cplusplus >= 201703L
-
-template<typename R>
-owning_view(R&&) -> owning_view<R>;
-
-#endif
-
 } // namespace ranges
 } // namespace namespace preview
 

include/preview/__ranges/range_adaptor_closure.h

@@ -38,6 +38,13 @@ struct basic_range {
   unsigned char data_;
 };
 
+struct ubiq_range {
+  ubiq_range() = default;
+
+  template<typename T, std::enable_if_t<range<remove_cvref_t<T>>::value, int> = 0>
+  operator T() const noexcept;
+};
+
 template<typename C, typename D>
 class range_adaptor_closure_object
     : protected compressed_pair<C, D>
@@ -75,7 +82,10 @@ template<typename T>
 struct is_range_adaptor_closure
     : conjunction<
           derived_from_single_crtp<T, range_adaptor_closure>,
-          is_invocable<T, detail::basic_range>,
+          disjunction<
+              is_invocable<T, detail::basic_range>,
+              is_invocable<T, detail::ubiq_range>
+          >,
           negation< range<T> >
       > {};
 
@@ -84,6 +94,8 @@ struct range_adaptor_closure {
   static_assert(std::is_object<Derived>::value, "Constraints not satisfied");
   static_assert(same_as<Derived, std::remove_cv_t<Derived>>::value, "Constraints not satisfied");
 
+  using _$preview_derived = Derived;
+
   template<typename Range, typename This, std::enable_if_t<conjunction<
       same_as<Derived, remove_cvref_t<This>>,
       range<remove_cvref_t<Range>>

include/preview/__ranges/subrange.h

@@ -70,42 +70,19 @@ struct make_unsigned_like<T, true> {
 template<typename T>
 using make_unsigned_like_t = typename make_unsigned_like<T>::type;
 
-template<typename T, typename U, typename V, bool = pair_like<T>::value /* true */>
+template<typename T, typename U, typename V, bool = pair_like<T>::value /* false */>
 struct pair_like_convertible_from
-    : conjunction<
-          negation< range<T> >,
-          negation< std::is_reference<T> >,
-          constructible_from<T, U, V>,
-          convertible_to_non_slicing<U, std::tuple_element_t<0, T>>,
-          convertible_to<V, std::tuple_element_t<1, T>>
-      > {};
+    : std::false_type {};
 
 template<typename T, typename U, typename V>
-struct pair_like_convertible_from<T, U, V, false> : std::false_type {};
-
-template<typename R, bool = borrowed_range<R>::value /* true */>
-struct borrowed_range_difference {
-  using type = range_difference_t<R>;
-};
-template<typename R>
-struct borrowed_range_difference<R, false> {};
-template<typename R>
-using borrowed_range_difference_t = typename borrowed_range_difference<R>::type;
-
-template<
-    typename I,
-    typename S = I,
-    subrange_kind K = sized_sentinel_for<S, I>::value ? subrange_kind::sized : subrange_kind::unsized
->
-struct is_subrange_constructible
+struct pair_like_convertible_from<T, U, V, true>
     : conjunction<
-          input_or_output_iterator<I>,
-          sentinel_for<S, I>,
-          disjunction<
-            bool_constant<(K == subrange_kind::sized)>,
-            negation< sized_sentinel_for<S, I> >
-          >
-      > {};
+        negation< range<T> >,
+        negation< std::is_reference<T> >,
+        constructible_from<T, U, V>,
+        convertible_to_non_slicing<U, std::tuple_element_t<0, T>>,
+        convertible_to<V, std::tuple_element_t<1, T>>
+    > {};
 
 template<typename I, typename S, bool Store /* false */>
 struct subrange_size {
@@ -123,18 +100,7 @@ struct subrange_size<I, S, true> {
   std::make_unsigned_t<iter_difference_t<I>> size_ = 0;
 };
 
-template<typename I, typename S, typename R, bool = borrowed_range<R>::value /* true */>
-struct subrange_ctor_range
-    : conjunction<
-          convertible_to_non_slicing<iterator_t<R>, I>,
-          convertible_to<sentinel_t<R>, S>
-      > {};
-
-template<typename I, typename S, typename R>
-struct subrange_ctor_range<I, S, R, false> : std::false_type {};
-
-
-}
+} // namespace detail
 
 template<
     typename I,
@@ -170,7 +136,9 @@ class subrange
 
   template<typename R, std::enable_if_t<conjunction<
       different_from<subrange, R>,
-      detail::subrange_ctor_range<I, S, R>,
+      borrowed_range<R>,
+      detail::convertible_to_non_slicing<iterator_t<R>, I>,
+      convertible_to<sentinel_t<R>, S>,
       disjunction<
           negation<store_size>,
           sized_range<R>
@@ -180,7 +148,9 @@ class subrange
       : subrange(r, static_cast<detail::make_unsigned_like_t<iter_difference_t<I>>>(ranges::size(r))) {}
 
   template<typename R, std::enable_if_t<conjunction<
-      detail::subrange_ctor_range<I, S, R>,
+      borrowed_range<R>,
+      detail::convertible_to_non_slicing<iterator_t<R>, I>,
+      convertible_to<sentinel_t<R>, S>,
       bool_constant< K == subrange_kind::sized >
   >::value, int> = 0>
   constexpr subrange(R&& r, detail::make_unsigned_like_t<iter_difference_t<I>> n)
@@ -297,16 +267,29 @@ make_subrange(R&& r, detail::make_unsigned_like_t<range_difference_t<R>> n) {
 }
 
 
-#if __cplusplus >= 201703L
-
-// template<typename R>
-// subrange(R&&, detail::make_unsigned_like_t<range_difference_t<R>>) ->
-//     subrange<ranges::iterator_t<R>, ranges::sentinel_t<R>, ranges::subrange_kind::sized>;
-//
-// template<typename I, typename S> subrange(I, S) -> subrange<I, S>;
-//
-// ^^^^^^^^^^ These two are ambiguous without constraints
+#if PREVIEW_CXX_VERSION >= 17
+// These two are ambiguous without constraints
+// vvvvvvvvvvvvvvvvvvvv
+template<typename R>
+subrange(R&&, detail::make_unsigned_like_t<range_difference_t<R>>) ->
+    subrange<
+            std::enable_if_t<borrowed_range<R>::value,
+        ranges::iterator_t<R>>,
+        ranges::sentinel_t<R>,
+        ranges::subrange_kind::sized
+    >;
 
+template<typename I, typename S>
+subrange(I, S)
+    -> subrange<
+            std::enable_if_t<conjunction<
+                input_or_output_iterator<I>,
+                sentinel_for<S, I>
+            >::value,
+        I>,
+        S
+    >;
+// ^^^^^^^^^^^^^^^^^^^^
 
 template<typename I, typename S>
 subrange(I, S, detail::make_unsigned_like_t<iter_difference_t<I>>) ->

include/preview/__ranges/views/all.h

@@ -15,6 +15,7 @@
 #include "preview/__ranges/ref_view.h"
 #include "preview/__ranges/view.h"
 #include "preview/__ranges/viewable_range.h"
+#include "preview/__type_traits/conditional.h"
 #include "preview/__type_traits/detail/return_category.h"
 #include "preview/__type_traits/conjunction.h"
 
@@ -28,17 +29,17 @@ using preview::detail::return_category;
 class all_adaptor_closure : public range_adaptor_closure<all_adaptor_closure> {
   template<typename T>
   using return_category_type =
-      std::conditional_t<
-          view<std::decay_t<T>>::value, return_category<1, std::decay_t<T>>,
-      std::conditional_t<
-          conjunction<
+      conditional_t<
+          view<std::decay_t<T>>, return_category<1, std::decay_t<T>>,
+          conjunction< // ref_view{T}
+              std::is_lvalue_reference<T>,
+              std::is_convertible<T, std::add_lvalue_reference_t<std::remove_reference_t<T>>>,
               range<std::remove_reference_t<T>>,
-              std::is_object<std::remove_reference_t<T>>,
-              std::is_lvalue_reference<T>
-          >::value,
-              return_category<2, ref_view<std::remove_reference_t<T>>>,
-              return_category<3, owning_view<std::remove_reference_t<T>>>
-      >>;
+              std::is_object<std::remove_reference_t<T>>
+          >,
+          return_category<2, ref_view<std::remove_reference_t<T>>>,
+          return_category<3, owning_view<std::remove_reference_t<T>>>
+      >;
 
   template<typename R, typename T>
   constexpr T operator()(R&& r, return_category<1, T>) const {
@@ -56,8 +57,6 @@ class all_adaptor_closure : public range_adaptor_closure<all_adaptor_closure> {
   }
 
  public:
-  all_adaptor_closure() = default;
-
   template<typename R>
   constexpr typename return_category_type<R&&>::return_type
   operator()(R&& r) const {