diff --git a/libcxx/include/__algorithm/in_found_result.h b/libcxx/include/__algorithm/in_found_result.h
--- a/libcxx/include/__algorithm/in_found_result.h
+++ b/libcxx/include/__algorithm/in_found_result.h
@@ -23,20 +23,20 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 namespace ranges {
-template <class _I1>
+template <class _InIter1>
 struct in_found_result {
-  _LIBCPP_NO_UNIQUE_ADDRESS _I1 in;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in;
   bool found;
 
-  template <class _I2>
-    requires convertible_to<const _I1&, _I2>
-  _LIBCPP_HIDE_FROM_ABI constexpr operator in_found_result<_I2>() const & {
+  template <class _InIter2>
+    requires convertible_to<const _InIter1&, _InIter2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator in_found_result<_InIter2>() const & {
     return {in, found};
   }
 
-  template <class _I2>
-    requires convertible_to<_I1, _I2>
-  _LIBCPP_HIDE_FROM_ABI constexpr operator in_found_result<_I2>() && {
+  template <class _InIter2>
+    requires convertible_to<_InIter1, _InIter2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator in_found_result<_InIter2>() && {
     return {std::move(in), found};
   }
 };
diff --git a/libcxx/include/__algorithm/in_fun_result.h b/libcxx/include/__algorithm/in_fun_result.h
--- a/libcxx/include/__algorithm/in_fun_result.h
+++ b/libcxx/include/__algorithm/in_fun_result.h
@@ -23,20 +23,20 @@
 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
 
 namespace ranges {
-template <class _Ip, class _Fp>
+template <class _InIter1, class _Func1>
 struct in_fun_result {
-  _LIBCPP_NO_UNIQUE_ADDRESS _Ip in;
-  _LIBCPP_NO_UNIQUE_ADDRESS _Fp fun;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in;
+  _LIBCPP_NO_UNIQUE_ADDRESS _Func1 fun;
 
-  template <class _I2, class _F2>
-    requires convertible_to<const _Ip&, _I2> && convertible_to<const _Fp&, _F2>
-  _LIBCPP_HIDE_FROM_ABI constexpr operator in_fun_result<_I2, _F2>() const & {
+  template <class _InIter2, class _Func2>
+    requires convertible_to<const _InIter1&, _InIter2> && convertible_to<const _Func1&, _Func2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator in_fun_result<_InIter2, _Func2>() const & {
     return {in, fun};
   }
 
-  template <class _I2, class _F2>
-    requires convertible_to<_Ip, _I2> && convertible_to<_Fp, _F2>
-  _LIBCPP_HIDE_FROM_ABI constexpr operator in_fun_result<_I2, _F2>() && {
+  template <class _InIter2, class _Func2>
+    requires convertible_to<_InIter1, _InIter2> && convertible_to<_Func1, _Func2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator in_fun_result<_InIter2, _Func2>() && {
     return {std::move(in), std::move(fun)};
   }
 };
diff --git a/libcxx/include/__algorithm/in_in_out_result.h b/libcxx/include/__algorithm/in_in_out_result.h
--- a/libcxx/include/__algorithm/in_in_out_result.h
+++ b/libcxx/include/__algorithm/in_in_out_result.h
@@ -24,23 +24,25 @@
 
 namespace ranges {
 
-template <class _I1, class _I2, class _O1>
+template <class _InIter1, class _InIter2, class _OutIter1>
 struct in_in_out_result {
-  _LIBCPP_NO_UNIQUE_ADDRESS _I1 in1;
-  _LIBCPP_NO_UNIQUE_ADDRESS _I2 in2;
-  _LIBCPP_NO_UNIQUE_ADDRESS _O1 out;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in1;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter2 in2;
+  _LIBCPP_NO_UNIQUE_ADDRESS _OutIter1 out;
 
-  template <class _II1, class _II2, class _OO1>
-    requires convertible_to<const _I1&, _II1> && convertible_to<const _I2&, _II2> && convertible_to<const _O1&, _OO1>
+  template <class _InIter3, class _InIter4, class _OutIter2>
+    requires convertible_to<const _InIter1&, _InIter3>
+          && convertible_to<const _InIter2&, _InIter4> && convertible_to<const _OutIter1&, _OutIter2>
   _LIBCPP_HIDE_FROM_ABI constexpr
-  operator in_in_out_result<_II1, _II2, _OO1>() const& {
+  operator in_in_out_result<_InIter3, _InIter4, _OutIter2>() const& {
     return {in1, in2, out};
   }
 
-  template <class _II1, class _II2, class _OO1>
-    requires convertible_to<_I1, _II1> && convertible_to<_I2, _II2> && convertible_to<_O1, _OO1>
+  template <class _InIter3, class _InIter4, class _OutIter2>
+    requires convertible_to<_InIter1, _InIter3>
+          && convertible_to<_InIter2, _InIter4> && convertible_to<_OutIter1, _OutIter2>
   _LIBCPP_HIDE_FROM_ABI constexpr
-  operator in_in_out_result<_II1, _II2, _OO1>() && {
+  operator in_in_out_result<_InIter3, _InIter4, _OutIter2>() && {
     return {std::move(in1), std::move(in2), std::move(out)};
   }
 };
diff --git a/libcxx/include/__algorithm/in_in_result.h b/libcxx/include/__algorithm/in_in_result.h
--- a/libcxx/include/__algorithm/in_in_result.h
+++ b/libcxx/include/__algorithm/in_in_result.h
@@ -24,22 +24,22 @@
 
 namespace ranges {
 
-template <class _I1, class _I2>
+template <class _InIter1, class _InIter2>
 struct in_in_result {
-  _LIBCPP_NO_UNIQUE_ADDRESS _I1 in1;
-  _LIBCPP_NO_UNIQUE_ADDRESS _I2 in2;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in1;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter2 in2;
 
-  template <class _II1, class _II2>
-    requires convertible_to<const _I1&, _II1> && convertible_to<const _I2&, _II2>
+  template <class _InIter3, class _InIter4>
+    requires convertible_to<const _InIter1&, _InIter3> && convertible_to<const _InIter2&, _InIter4>
    _LIBCPP_HIDE_FROM_ABI constexpr
-   operator in_in_result<_II1, _II2>() const & {
+   operator in_in_result<_InIter3, _InIter4>() const & {
     return {in1, in2};
   }
 
-  template <class _II1, class _II2>
-    requires convertible_to<_I1, _II1> && convertible_to<_I2, _II2>
+  template <class _InIter3, class _InIter4>
+    requires convertible_to<_InIter1, _InIter3> && convertible_to<_InIter2, _InIter4>
   _LIBCPP_HIDE_FROM_ABI constexpr
-  operator in_in_result<_II1, _II2>() && {
+  operator in_in_result<_InIter3, _InIter4>() && {
     return {std::move(in1), std::move(in2)};
   }
 };
diff --git a/libcxx/include/__algorithm/in_out_out_result.h b/libcxx/include/__algorithm/in_out_out_result.h
--- a/libcxx/include/__algorithm/in_out_out_result.h
+++ b/libcxx/include/__algorithm/in_out_out_result.h
@@ -23,23 +23,25 @@
 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
 
 namespace ranges {
-template <class _I1, class _O1, class _O2>
+template <class _InIter1, class _OutIter1, class _OutIter2>
 struct in_out_out_result {
-  _LIBCPP_NO_UNIQUE_ADDRESS _I1 in;
-  _LIBCPP_NO_UNIQUE_ADDRESS _O1 out1;
-  _LIBCPP_NO_UNIQUE_ADDRESS _O2 out2;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in;
+  _LIBCPP_NO_UNIQUE_ADDRESS _OutIter1 out1;
+  _LIBCPP_NO_UNIQUE_ADDRESS _OutIter2 out2;
 
-  template <class _II1, class _OO1, class _OO2>
-    requires convertible_to<const _I1&, _II1> && convertible_to<const _O1&, _OO1> && convertible_to<const _O2&, _OO2>
+  template <class _InIter2, class _OutIter3, class _OutIter4>
+    requires convertible_to<const _InIter1&, _InIter2>
+          && convertible_to<const _OutIter1&, _OutIter3> && convertible_to<const _OutIter2&, _OutIter4>
   _LIBCPP_HIDE_FROM_ABI constexpr
-  operator in_out_out_result<_II1, _OO1, _OO2>() const& {
+  operator in_out_out_result<_InIter2, _OutIter3, _OutIter4>() const& {
     return {in, out1, out2};
   }
 
-  template <class _II1, class _OO1, class _OO2>
-    requires convertible_to<_I1, _II1> && convertible_to<_O1, _OO1> && convertible_to<_O2, _OO2>
+  template <class _InIter2, class _OutIter3, class _OutIter4>
+    requires convertible_to<_InIter1, _InIter2>
+          && convertible_to<_OutIter1, _OutIter3> && convertible_to<_OutIter2, _OutIter4>
   _LIBCPP_HIDE_FROM_ABI constexpr
-  operator in_out_out_result<_II1, _OO1, _OO2>() && {
+  operator in_out_out_result<_InIter2, _OutIter3, _OutIter4>() && {
     return {std::move(in), std::move(out1), std::move(out2)};
   }
 };
diff --git a/libcxx/include/__algorithm/in_out_result.h b/libcxx/include/__algorithm/in_out_result.h
--- a/libcxx/include/__algorithm/in_out_result.h
+++ b/libcxx/include/__algorithm/in_out_result.h
@@ -24,22 +24,22 @@
 
 namespace ranges {
 
-template<class _I1, class _O1>
+template<class _InIter1, class _OutIter1>
 struct in_out_result {
-  _LIBCPP_NO_UNIQUE_ADDRESS _I1 in;
-  _LIBCPP_NO_UNIQUE_ADDRESS _O1 out;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in;
+  _LIBCPP_NO_UNIQUE_ADDRESS _OutIter1 out;
 
-  template <class _I2, class _O2>
-    requires convertible_to<const _I1&, _I2> && convertible_to<const _O1&, _O2>
+  template <class _InIter2, class _OutIter2>
+    requires convertible_to<const _InIter1&, _InIter2> && convertible_to<const _OutIter1&, _OutIter2>
   _LIBCPP_HIDE_FROM_ABI
-  constexpr operator in_out_result<_I2, _O2>() const & {
+  constexpr operator in_out_result<_InIter2, _OutIter2>() const & {
     return {in, out};
   }
 
-  template <class _I2, class _O2>
-    requires convertible_to<_I1, _I2> && convertible_to<_O1, _O2>
+  template <class _InIter2, class _OutIter2>
+    requires convertible_to<_InIter1, _InIter2> && convertible_to<_OutIter1, _OutIter2>
   _LIBCPP_HIDE_FROM_ABI
-  constexpr operator in_out_result<_I2, _O2>() && {
+  constexpr operator in_out_result<_InIter2, _OutIter2>() && {
     return {std::move(in), std::move(out)};
   }
 };