From b56cbdd23834a65682c0b46f367f8679e83bc894 Mon Sep 17 00:00:00 2001
From: Abseil Team <absl-team@google.com>
Date: Fri, 18 Sep 2020 15:55:15 -0700
Subject: Abseil LTS 20200923

What's New:
* `absl::StatusOr<T>` has been released. See our [blog
  post](https://abseil.io/blog/2020-091021-status) for more
  information.
* Abseil Flags reflection interfaces have been released.
* Abseil Flags memory usage has been significantly optimized.
* Abseil now supports a "hardened" build mode. This build mode enables
  runtime checks that guard against programming errors that may lead
  to security vulnerabilities.

Notable Fixes:
* Sanitizer dynamic annotations like `AnnotateRWLockCreate` that are
  also defined by the compiler sanitizer implementation are no longer
  also defined by Abseil.
* Sanitizer macros are now prefixed with `ABSL_` to avoid naming collisions.
* Sanitizer usage is now automatically detected and no longer requires
  macros like `ADDRESS_SANITIZER` to be defined on the command line.

Breaking Changes:
* Abseil no longer contains a `dynamic_annotations` library. Users
  using a supported build system (Bazel or CMake) are unaffected by
  this, but users manually specifying link libraries may get an error
  about a missing linker input.

Baseline: 7680a5f8efe32de4753baadbd63e74e59d95bac1
Cherry picks: None
---
 absl/container/internal/compressed_tuple.h | 41 ++++++++++++++++++++++++------
 1 file changed, 33 insertions(+), 8 deletions(-)

(limited to 'absl/container/internal/compressed_tuple.h')

diff --git a/absl/container/internal/compressed_tuple.h b/absl/container/internal/compressed_tuple.h
index 4bfe92fd..02bfd03f 100644
--- a/absl/container/internal/compressed_tuple.h
+++ b/absl/container/internal/compressed_tuple.h
@@ -169,9 +169,33 @@ constexpr bool ShouldAnyUseBase() {
 }
 
 template <typename T, typename V>
-using TupleMoveConstructible = typename std::conditional<
-      std::is_reference<T>::value, std::is_convertible<V, T>,
-      std::is_constructible<T, V&&>>::type;
+using TupleElementMoveConstructible =
+    typename std::conditional<std::is_reference<T>::value,
+                              std::is_convertible<V, T>,
+                              std::is_constructible<T, V&&>>::type;
+
+template <bool SizeMatches, class T, class... Vs>
+struct TupleMoveConstructible : std::false_type {};
+
+template <class... Ts, class... Vs>
+struct TupleMoveConstructible<true, CompressedTuple<Ts...>, Vs...>
+    : std::integral_constant<
+          bool, absl::conjunction<
+                    TupleElementMoveConstructible<Ts, Vs&&>...>::value> {};
+
+template <typename T>
+struct compressed_tuple_size;
+
+template <typename... Es>
+struct compressed_tuple_size<CompressedTuple<Es...>>
+    : public std::integral_constant<std::size_t, sizeof...(Es)> {};
+
+template <class T, class... Vs>
+struct TupleItemsMoveConstructible
+    : std::integral_constant<
+          bool, TupleMoveConstructible<compressed_tuple_size<T>::value ==
+                                           sizeof...(Vs),
+                                       T, Vs...>::value> {};
 
 }  // namespace internal_compressed_tuple
 
@@ -217,17 +241,18 @@ class ABSL_INTERNAL_COMPRESSED_TUPLE_DECLSPEC CompressedTuple
   explicit constexpr CompressedTuple(const Ts&... base)
       : CompressedTuple::CompressedTupleImpl(absl::in_place, base...) {}
 
-  template <typename... Vs,
+  template <typename First, typename... Vs,
             absl::enable_if_t<
                 absl::conjunction<
                     // Ensure we are not hiding default copy/move constructors.
                     absl::negation<std::is_same<void(CompressedTuple),
-                                                void(absl::decay_t<Vs>...)>>,
-                    internal_compressed_tuple::TupleMoveConstructible<
-                        Ts, Vs&&>...>::value,
+                                                void(absl::decay_t<First>)>>,
+                    internal_compressed_tuple::TupleItemsMoveConstructible<
+                        CompressedTuple<Ts...>, First, Vs...>>::value,
                 bool> = true>
-  explicit constexpr CompressedTuple(Vs&&... base)
+  explicit constexpr CompressedTuple(First&& first, Vs&&... base)
       : CompressedTuple::CompressedTupleImpl(absl::in_place,
+                                             absl::forward<First>(first),
                                              absl::forward<Vs>(base)...) {}
 
   template <int I>
-- 
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