[libc++][NFC] Remove __remove_uncvref

[philnik777]

The use-case for __is_same_uncvref seems rather dubious, since not a single use-cases needed the remove_cvref_t to be applied to both of the arguments. Removing the alias makes it clearer what actually happens, since we're not using an internal name anymore and it's clear what the remove_cvref_t should apply to.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

Changes

The use-case for __is_same_uncvref seems rather dubious, since not a single use-cases needed the remove_cvref_t to be applied to both of the arguments. Removing the alias makes it clearer what actually happens, since we're not using an internal name anymore and it's clear what the remove_cvref_t should apply to.

---

Full diff: https://github.com/llvm/llvm-project/pull/140531.diff

6 Files Affected:

• (modified) libcxx/include/__functional/boyer_moore_searcher.h (+4-4)
• (modified) libcxx/include/__functional/reference_wrapper.h (+2-1)
• (modified) libcxx/include/__hash_table (+3-3)
• (modified) libcxx/include/__type_traits/remove_cvref.h (-4)
• (modified) libcxx/include/string (+11-11)
• (modified) libcxx/test/libcxx/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp (+3-2)

diff --git a/libcxx/include/__functional/boyer_moore_searcher.h b/libcxx/include/__functional/boyer_moore_searcher.h
index 7889232f4b919..019d470487081 100644
--- a/libcxx/include/__functional/boyer_moore_searcher.h
+++ b/libcxx/include/__functional/boyer_moore_searcher.h
@@ -125,8 +125,8 @@ class boyer_moore_searcher {
   template <class _RandomAccessIterator2>
   _LIBCPP_HIDE_FROM_ABI pair<_RandomAccessIterator2, _RandomAccessIterator2>
   operator()(_RandomAccessIterator2 __first, _RandomAccessIterator2 __last) const {
-    static_assert(__is_same_uncvref<typename iterator_traits<_RandomAccessIterator1>::value_type,
-                                    typename iterator_traits<_RandomAccessIterator2>::value_type>::value,
+    static_assert(is_same_v<typename iterator_traits<_RandomAccessIterator1>::value_type,
+                            typename iterator_traits<_RandomAccessIterator2>::value_type>,
                   "Corpus and Pattern iterators must point to the same type");
     if (__first == __last)
       return std::make_pair(__last, __last);
@@ -256,8 +256,8 @@ class boyer_moore_horspool_searcher {
   template <class _RandomAccessIterator2>
   _LIBCPP_HIDE_FROM_ABI pair<_RandomAccessIterator2, _RandomAccessIterator2>
   operator()(_RandomAccessIterator2 __first, _RandomAccessIterator2 __last) const {
-    static_assert(__is_same_uncvref<typename std::iterator_traits<_RandomAccessIterator1>::value_type,
-                                    typename std::iterator_traits<_RandomAccessIterator2>::value_type>::value,
+    static_assert(is_same_v<typename std::iterator_traits<_RandomAccessIterator1>::value_type,
+                            typename std::iterator_traits<_RandomAccessIterator2>::value_type>,
                   "Corpus and Pattern iterators must point to the same type");
     if (__first == __last)
       return std::make_pair(__last, __last);
diff --git a/libcxx/include/__functional/reference_wrapper.h b/libcxx/include/__functional/reference_wrapper.h
index c46203a4ca9a4..11ba364369428 100644
--- a/libcxx/include/__functional/reference_wrapper.h
+++ b/libcxx/include/__functional/reference_wrapper.h
@@ -19,6 +19,7 @@
 #include <__type_traits/invoke.h>
 #include <__type_traits/is_const.h>
 #include <__type_traits/is_core_convertible.h>
+#include <__type_traits/is_same.h>
 #include <__type_traits/remove_cvref.h>
 #include <__type_traits/void_t.h>
 #include <__utility/declval.h>
@@ -45,7 +46,7 @@ class reference_wrapper : public __weak_result_type<_Tp> {
 public:
   template <class _Up,
             class = __void_t<decltype(__fun(std::declval<_Up>()))>,
-            __enable_if_t<!__is_same_uncvref<_Up, reference_wrapper>::value, int> = 0>
+            __enable_if_t<!is_same<__remove_cvref_t<_Up>, reference_wrapper>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference_wrapper(_Up&& __u)
       _NOEXCEPT_(noexcept(__fun(std::declval<_Up>()))) {
     type& __f = static_cast<_Up&&>(__u);
diff --git a/libcxx/include/__hash_table b/libcxx/include/__hash_table
index cc5f6d1348e41..4ab67a20dacc3 100644
--- a/libcxx/include/__hash_table
+++ b/libcxx/include/__hash_table
@@ -207,12 +207,12 @@ struct __hash_key_value_types<__hash_value_type<_Key, _Tp> > {
 
   _LIBCPP_HIDE_FROM_ABI static key_type const& __get_key(__container_value_type const& __v) { return __v.first; }
 
-  template <class _Up, __enable_if_t<__is_same_uncvref<_Up, __node_value_type>::value, int> = 0>
+  template <class _Up, __enable_if_t<is_same<__remove_cvref_t<_Up>, __node_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI static __container_value_type const& __get_value(_Up& __t) {
     return __t.__get_value();
   }
 
-  template <class _Up, __enable_if_t<__is_same_uncvref<_Up, __container_value_type>::value, int> = 0>
+  template <class _Up, __enable_if_t<is_same<__remove_cvref_t<_Up>, __container_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI static __container_value_type const& __get_value(_Up& __t) {
     return __t;
   }
@@ -856,7 +856,7 @@ public:
     return __emplace_unique_key_args(_NodeTypes::__get_key(__x), std::move(__x));
   }
 
-  template <class _Pp, __enable_if_t<!__is_same_uncvref<_Pp, __container_value_type>::value, int> = 0>
+  template <class _Pp, __enable_if_t<!is_same<__remove_cvref_t<_Pp>, __container_value_type>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __insert_unique(_Pp&& __x) {
     return __emplace_unique(std::forward<_Pp>(__x));
   }
diff --git a/libcxx/include/__type_traits/remove_cvref.h b/libcxx/include/__type_traits/remove_cvref.h
index 760deddca946d..c568e8df3099d 100644
--- a/libcxx/include/__type_traits/remove_cvref.h
+++ b/libcxx/include/__type_traits/remove_cvref.h
@@ -10,7 +10,6 @@
 #define _LIBCPP___TYPE_TRAITS_REMOVE_CVREF_H
 
 #include <__config>
-#include <__type_traits/is_same.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -31,9 +30,6 @@ template <class _Tp>
 using __remove_cvref_t _LIBCPP_NODEBUG = __remove_cvref(_Tp);
 #endif // __has_builtin(__remove_cvref)
 
-template <class _Tp, class _Up>
-using __is_same_uncvref _LIBCPP_NODEBUG = _IsSame<__remove_cvref_t<_Tp>, __remove_cvref_t<_Up> >;
-
 #if _LIBCPP_STD_VER >= 20
 template <class _Tp>
 struct _LIBCPP_NO_SPECIALIZATIONS remove_cvref {
diff --git a/libcxx/include/string b/libcxx/include/string
index c450ddcb41914..514dd91c7c172 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -1126,7 +1126,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
   basic_string(const _Tp& __t, size_type __pos, size_type __n, const allocator_type& __a = allocator_type())
@@ -1138,7 +1138,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(const _Tp& __t) {
     __self_view __sv = __t;
@@ -1147,7 +1147,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit basic_string(const _Tp& __t, const allocator_type& __a)
       : __alloc_(__a) {
@@ -1206,7 +1206,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(const _Tp& __t) {
     __self_view __sv = __t;
@@ -1343,7 +1343,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string >::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string >::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator+=(const _Tp& __t) {
     __self_view __sv = __t;
@@ -1372,7 +1372,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& append(const _Tp& __t) {
     __self_view __sv = __t;
@@ -1383,7 +1383,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
   append(const _Tp& __t, size_type __pos, size_type __n = npos) {
@@ -1510,7 +1510,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
   assign(const _Tp& __t, size_type __pos, size_type __n = npos) {
@@ -1580,7 +1580,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
   insert(size_type __pos1, const _Tp& __t, size_type __pos2, size_type __n = npos) {
@@ -1661,7 +1661,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string&
   replace(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2 = npos) {
@@ -2006,7 +2006,7 @@ public:
 
   template <class _Tp,
             __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
-                              !__is_same_uncvref<_Tp, basic_string>::value,
+                              !is_same<__remove_cvref_t<_Tp>, basic_string>::value,
                           int> = 0>
   inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
   compare(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2 = npos) const {
diff --git a/libcxx/test/libcxx/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp b/libcxx/test/libcxx/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp
index 48460d1488fd7..32f8d45fbbc95 100644
--- a/libcxx/test/libcxx/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp
+++ b/libcxx/test/libcxx/utilities/function.objects/func.require/bullet_1_2_3.pass.cpp
@@ -254,8 +254,9 @@ struct ReferenceWrapper {
     static void fun(Type&) noexcept;
     static void fun(Type&&) = delete;
 
-    template <class Type2,
-              class = typename std::enable_if<!std::__is_same_uncvref<Type2, ReferenceWrapper>::value>::type>
+    template <
+        class Type2,
+        class = typename std::enable_if<!std::is_same<std::__remove_cvref_t<Type2>, ReferenceWrapper>::value>::type>
     constexpr ReferenceWrapper(Type2&& t) noexcept : ptr(&t) {}
 
     constexpr Type& get() const noexcept { return *ptr; }

[ldionne]

LGTM with minor comment.