[libc++][ranges] remove __workaround_52970 (#85683)

## Abstract

This pull request removes the `__workaround_52970` concept. This concept
is a workaround for a bug described in #52970, which causes the compiler
to trigger ADL on a pointer to an incomplete type in an SFINAE context.
This bug is fixed in Clang 14.

## Reference

- [[clang] Don't typo-fix an expression in a SFINAE
context](https://reviews.llvm.org/D117603)
- [[libc++] [ranges] ADL-proof the [range.access]
CPOs.](https://reviews.llvm.org/D116239)

Author: Xiaoyang Liu

libcxx/include/__concepts/class_or_enum.h

@@ -28,11 +28,6 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 template <class _Tp>
 concept __class_or_enum = is_class_v<_Tp> || is_union_v<_Tp> || is_enum_v<_Tp>;
 
-// Work around Clang bug https://llvm.org/PR52970
-// TODO: remove this workaround once libc++ no longer has to support Clang 13 (it was fixed in Clang 14).
-template <class _Tp>
-concept __workaround_52970 = is_class_v<__remove_cvref_t<_Tp>> || is_union_v<__remove_cvref_t<_Tp>>;
-
 #endif // _LIBCPP_STD_VER >= 20
 
 _LIBCPP_END_NAMESPACE_STD

libcxx/include/__ranges/access.h

@@ -41,7 +41,7 @@ concept __can_borrow = is_lvalue_reference_v<_Tp> || enable_borrowed_range<remov
 namespace ranges {
 namespace __begin {
 template <class _Tp>
-concept __member_begin = __can_borrow<_Tp> && __workaround_52970<_Tp> && requires(_Tp&& __t) {
+concept __member_begin = __can_borrow<_Tp> && requires(_Tp&& __t) {
   { _LIBCPP_AUTO_CAST(__t.begin()) } -> input_or_output_iterator;
 };
 
@@ -103,7 +103,7 @@ using iterator_t = decltype(ranges::begin(std::declval<_Tp&>()));
 namespace ranges {
 namespace __end {
 template <class _Tp>
-concept __member_end = __can_borrow<_Tp> && __workaround_52970<_Tp> && requires(_Tp&& __t) {
+concept __member_end = __can_borrow<_Tp> && requires(_Tp&& __t) {
   typename iterator_t<_Tp>;
   { _LIBCPP_AUTO_CAST(__t.end()) } -> sentinel_for<iterator_t<_Tp>>;
 };

libcxx/include/__ranges/data.h

@@ -40,7 +40,7 @@ template <class _Tp>
 concept __ptr_to_object = is_pointer_v<_Tp> && is_object_v<remove_pointer_t<_Tp>>;
 
 template <class _Tp>
-concept __member_data = __can_borrow<_Tp> && __workaround_52970<_Tp> && requires(_Tp&& __t) {
+concept __member_data = __can_borrow<_Tp> && requires(_Tp&& __t) {
   { _LIBCPP_AUTO_CAST(__t.data()) } -> __ptr_to_object;
 };
 

libcxx/include/__ranges/empty.h

@@ -29,7 +29,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 namespace ranges {
 namespace __empty {
 template <class _Tp>
-concept __member_empty = __workaround_52970<_Tp> && requires(_Tp&& __t) { bool(__t.empty()); };
+concept __member_empty = requires(_Tp&& __t) { bool(__t.empty()); };
 
 template <class _Tp>
 concept __can_invoke_size = !__member_empty<_Tp> && requires(_Tp&& __t) { ranges::size(__t); };

libcxx/include/__ranges/rbegin.h

@@ -36,7 +36,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 namespace ranges {
 namespace __rbegin {
 template <class _Tp>
-concept __member_rbegin = __can_borrow<_Tp> && __workaround_52970<_Tp> && requires(_Tp&& __t) {
+concept __member_rbegin = __can_borrow<_Tp> && requires(_Tp&& __t) {
   { _LIBCPP_AUTO_CAST(__t.rbegin()) } -> input_or_output_iterator;
 };
 

libcxx/include/__ranges/rend.h

@@ -37,7 +37,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 namespace ranges {
 namespace __rend {
 template <class _Tp>
-concept __member_rend = __can_borrow<_Tp> && __workaround_52970<_Tp> && requires(_Tp&& __t) {
+concept __member_rend = __can_borrow<_Tp> && requires(_Tp&& __t) {
   ranges::rbegin(__t);
   { _LIBCPP_AUTO_CAST(__t.rend()) } -> sentinel_for<decltype(ranges::rbegin(__t))>;
 };

libcxx/include/__ranges/size.h

@@ -47,7 +47,7 @@ template <class _Tp>
 concept __size_enabled = !disable_sized_range<remove_cvref_t<_Tp>>;
 
 template <class _Tp>
-concept __member_size = __size_enabled<_Tp> && __workaround_52970<_Tp> && requires(_Tp&& __t) {
+concept __member_size = __size_enabled<_Tp> && requires(_Tp&& __t) {
   { _LIBCPP_AUTO_CAST(__t.size()) } -> __integer_like;
 };