1 files changed, 36 insertions, 26 deletions
diff --git a/libcxx/include/__algorithm/ranges_remove_copy_if.h b/libcxx/include/__algorithm/ranges_remove_copy_if.h
index 4eafe425b8e3..4fc67454b926 100644
--- a/libcxx/include/__algorithm/ranges_remove_copy_if.h
+++ b/libcxx/include/__algorithm/ranges_remove_copy_if.h
@@ -29,7 +29,7 @@
 #  pragma GCC system_header
 #endif
 
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+#if _LIBCPP_STD_VER > 17
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
@@ -38,33 +38,43 @@ namespace ranges {
 template <class _InIter, class _OutIter>
 using remove_copy_if_result = in_out_result<_InIter, _OutIter>;
 
-namespace __remove_copy_if {
-
-struct __fn {
-
-  template <input_iterator _InIter, sentinel_for<_InIter> _Sent, weakly_incrementable _OutIter,
-            class _Proj = identity, indirect_unary_predicate<projected<_InIter, _Proj>> _Pred>
-  requires indirectly_copyable<_InIter, _OutIter>
-  _LIBCPP_HIDE_FROM_ABI constexpr
-  remove_copy_if_result<_InIter, _OutIter>
-  operator()(_InIter __first, _Sent __last, _OutIter __result, _Pred __pred, _Proj __proj = {}) const {
-    // TODO: implement
-    (void)__first; (void)__last; (void)__result; (void)__pred; (void)__proj;
-    return {};
+template <class _InIter, class _Sent, class _OutIter, class _Proj, class _Pred>
+_LIBCPP_HIDE_FROM_ABI constexpr in_out_result<_InIter, _OutIter>
+__remove_copy_if_impl(_InIter __first, _Sent __last, _OutIter __result, _Pred& __pred, _Proj& __proj) {
+  for (; __first != __last; ++__first) {
+    if (!std::invoke(__pred, std::invoke(__proj, *__first))) {
+      *__result = *__first;
+      ++__result;
+    }
   }
+  return {std::move(__first), std::move(__result)};
+}
 
-  template <input_range _Range, weakly_incrementable _OutIter, class _Proj = identity,
-            indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
-  requires indirectly_copyable<iterator_t<_Range>, _OutIter>
-  _LIBCPP_HIDE_FROM_ABI constexpr
-  remove_copy_if_result<borrowed_iterator_t<_Range>, _OutIter>
-  operator()(_Range&& __range, _OutIter __result, _Pred __pred, _Proj __proj = {}) const {
-    // TODO: implement
-    (void)__range; (void)__result; (void)__pred; (void)__proj;
-    return {};
-  }
+namespace __remove_copy_if {
 
-};
+  struct __fn {
+    template <input_iterator _InIter,
+              sentinel_for<_InIter> _Sent,
+              weakly_incrementable _OutIter,
+              class _Proj = identity,
+              indirect_unary_predicate<projected<_InIter, _Proj>> _Pred>
+      requires indirectly_copyable<_InIter, _OutIter>
+    _LIBCPP_HIDE_FROM_ABI constexpr remove_copy_if_result<_InIter, _OutIter>
+    operator()(_InIter __first, _Sent __last, _OutIter __result, _Pred __pred, _Proj __proj = {}) const {
+      return ranges::__remove_copy_if_impl(std::move(__first), std::move(__last), std::move(__result), __pred, __proj);
+    }
+
+    template <input_range _Range,
+              weakly_incrementable _OutIter,
+              class _Proj = identity,
+              indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
+      requires indirectly_copyable<iterator_t<_Range>, _OutIter>
+    _LIBCPP_HIDE_FROM_ABI constexpr remove_copy_if_result<borrowed_iterator_t<_Range>, _OutIter>
+    operator()(_Range&& __range, _OutIter __result, _Pred __pred, _Proj __proj = {}) const {
+      return ranges::__remove_copy_if_impl(
+          ranges::begin(__range), ranges::end(__range), std::move(__result), __pred, __proj);
+    }
+  };
 
 } // namespace __remove_copy_if
 
@@ -75,6 +85,6 @@ inline namespace __cpo {
 
 _LIBCPP_END_NAMESPACE_STD
 
-#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+#endif // _LIBCPP_STD_VER > 17
 
 #endif // _LIBCPP___ALGORITHM_RANGES_REMOVE_COPY_IF_H