From 3618ec4705e9c642384c683eb8d80ee3cd6b7f9e Mon Sep 17 00:00:00 2001
From: Eric Niebler <eniebler@boost.org>
Date: Thu, 6 Aug 2020 15:41:55 -0600
Subject: [PATCH] replace safe_subrange_t with borrowed_subrange_t

---
 include/range/v3/algorithm/equal_range.hpp |  2 +-
 include/range/v3/algorithm/find_end.hpp    |  2 +-
 include/range/v3/algorithm/rotate.hpp      |  2 +-
 include/range/v3/algorithm/search.hpp      |  2 +-
 include/range/v3/algorithm/search_n.hpp    |  2 +-
 include/range/v3/view/subrange.hpp         | 12 ++++++++++--
 test/view/subrange.cpp                     |  4 ++--
 7 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/include/range/v3/algorithm/equal_range.hpp b/include/range/v3/algorithm/equal_range.hpp
index 0a3f3c7fca..f8e0ea6427 100644
--- a/include/range/v3/algorithm/equal_range.hpp
+++ b/include/range/v3/algorithm/equal_range.hpp
@@ -105,7 +105,7 @@ namespace ranges
             /// \pre
             requires forward_range<Rng> AND
                 indirect_strict_weak_order<C, V const *, projected<iterator_t<Rng>, P>>)
-        safe_subrange_t<Rng> //
+        borrowed_subrange_t<Rng> //
         RANGES_FUNC(equal_range)(Rng && rng, V const & val, C pred = C{}, P proj = P{}) //
         {
             if(RANGES_CONSTEXPR_IF(sized_range<Rng>))
diff --git a/include/range/v3/algorithm/find_end.hpp b/include/range/v3/algorithm/find_end.hpp
index 340d92d419..89ef3139a2 100644
--- a/include/range/v3/algorithm/find_end.hpp
+++ b/include/range/v3/algorithm/find_end.hpp
@@ -217,7 +217,7 @@ namespace ranges
             /// \pre
             requires forward_range<Rng1> AND forward_range<Rng2> AND
                 indirect_relation<R, projected<iterator_t<Rng1>, P>, iterator_t<Rng2>>)
-        safe_subrange_t<Rng1> RANGES_FUNC(find_end)(
+        borrowed_subrange_t<Rng1> RANGES_FUNC(find_end)(
             Rng1 && rng1, Rng2 && rng2, R pred = R{}, P proj = P{}) //
         {
             return (*this)(begin(rng1),
diff --git a/include/range/v3/algorithm/rotate.hpp b/include/range/v3/algorithm/rotate.hpp
index 4e8713e24e..5a0b6976b2 100644
--- a/include/range/v3/algorithm/rotate.hpp
+++ b/include/range/v3/algorithm/rotate.hpp
@@ -217,7 +217,7 @@ namespace ranges
         template(typename Rng, typename I = iterator_t<Rng>)(
             /// \pre
             requires range<Rng> AND permutable<I>)
-        safe_subrange_t<Rng> RANGES_FUNC(rotate)(Rng && rng, I middle) //
+        borrowed_subrange_t<Rng> RANGES_FUNC(rotate)(Rng && rng, I middle) //
         {
             return (*this)(begin(rng), std::move(middle), end(rng));
         }
diff --git a/include/range/v3/algorithm/search.hpp b/include/range/v3/algorithm/search.hpp
index ecf1b54099..62fdcaa7fc 100644
--- a/include/range/v3/algorithm/search.hpp
+++ b/include/range/v3/algorithm/search.hpp
@@ -197,7 +197,7 @@ namespace ranges
             /// \pre
             requires forward_range<Rng1> AND forward_range<Rng2> AND
                 indirectly_comparable<iterator_t<Rng1>, iterator_t<Rng2>, C, P1, P2>)
-        safe_subrange_t<Rng1> RANGES_FUNC(search)(
+        borrowed_subrange_t<Rng1> RANGES_FUNC(search)(
             Rng1 && rng1, Rng2 && rng2, C pred = C{}, P1 proj1 = P1{}, P2 proj2 = P2{}) //
         {
             if(empty(rng2))
diff --git a/include/range/v3/algorithm/search_n.hpp b/include/range/v3/algorithm/search_n.hpp
index 9fa827448a..c87eaaea86 100644
--- a/include/range/v3/algorithm/search_n.hpp
+++ b/include/range/v3/algorithm/search_n.hpp
@@ -170,7 +170,7 @@ namespace ranges
             /// \pre
             requires forward_range<Rng> AND
                 indirectly_comparable<iterator_t<Rng>, V const *, C, P>)
-        safe_subrange_t<Rng> RANGES_FUNC(search_n)(Rng && rng,
+        borrowed_subrange_t<Rng> RANGES_FUNC(search_n)(Rng && rng,
                                                    iter_difference_t<iterator_t<Rng>> cnt,
                                                    V const & val,
                                                    C pred = C{},
diff --git a/include/range/v3/view/subrange.hpp b/include/range/v3/view/subrange.hpp
index 79f096a05d..73829cfa2d 100644
--- a/include/range/v3/view/subrange.hpp
+++ b/include/range/v3/view/subrange.hpp
@@ -431,7 +431,11 @@ namespace ranges
     RANGES_INLINE_VARIABLE(make_subrange_fn, make_subrange)
 
     template<typename R>
-    using safe_subrange_t = detail::maybe_dangling_<R, subrange<iterator_t<R>>>;
+    using borrowed_subrange_t = detail::maybe_dangling_<R, subrange<iterator_t<R>>>;
+
+    template<typename R>
+    using safe_subrange_t RANGES_DEPRECATED("Use borrowed_subrange_t instead.") =
+        borrowed_subrange_t<R>;
 
     namespace cpp20
     {
@@ -447,7 +451,11 @@ namespace ranges
                 (K == subrange_kind::sized || !sized_sentinel_for<S, I>))   //
         using subrange = ranges::subrange<I, S, K>;
 
-        using ranges::safe_subrange_t;
+        using ranges::borrowed_subrange_t;
+
+        template<typename R>
+        using safe_subrange_t RANGES_DEPRECATED("Use borrowed_subrange_t instead.") =
+            borrowed_subrange_t<R>;
     } // namespace cpp20
     /// @}
 } // namespace ranges
diff --git a/test/view/subrange.cpp b/test/view/subrange.cpp
index aced0f3464..26c157ae6b 100644
--- a/test/view/subrange.cpp
+++ b/test/view/subrange.cpp
@@ -21,7 +21,7 @@
 
 CPP_template(class Rng)(
     requires ranges::range<Rng>)
-ranges::safe_subrange_t<Rng> algorithm(Rng &&rng);
+ranges::borrowed_subrange_t<Rng> algorithm(Rng &&rng);
 
 struct Base {};
 struct Derived : Base {};
@@ -33,7 +33,7 @@ int main()
     std::vector<int> vi{1,2,3,4};
 
     ////////////////////////////////////////////////////////////////////////////
-    // safe_subrange_t tests:
+    // borrowed_subrange_t tests:
 
     // lvalues are ReferenceableRanges and do not dangle:
     CPP_assert(same_as<subrange<int*>,