From 082c006c04343a78d87b6c6ab3608c25d6213c3f Mon Sep 17 00:00:00 2001
From: Vincent Ambo <mail@tazj.in>
Date: Sat, 21 Nov 2020 14:43:54 +0100
Subject: merge(3p/absl): subtree merge of Abseil up to e19260f

... notably, this includes Abseil's own StatusOr type, which
conflicted with our implementation (that was taken from TensorFlow).

Change-Id: Ie7d6764b64055caaeb8dc7b6b9d066291e6b538f
---
 third_party/abseil_cpp/absl/meta/BUILD.bazel   |  2 +-
 third_party/abseil_cpp/absl/meta/type_traits.h | 28 +++++++++++++++++---------
 2 files changed, 19 insertions(+), 11 deletions(-)

(limited to 'third_party/abseil_cpp/absl/meta')

diff --git a/third_party/abseil_cpp/absl/meta/BUILD.bazel b/third_party/abseil_cpp/absl/meta/BUILD.bazel
index c06d2d9708c1..5585fcca794a 100644
--- a/third_party/abseil_cpp/absl/meta/BUILD.bazel
+++ b/third_party/abseil_cpp/absl/meta/BUILD.bazel
@@ -24,7 +24,7 @@ load(
 
 package(default_visibility = ["//visibility:public"])
 
-licenses(["notice"])  # Apache 2.0
+licenses(["notice"])
 
 cc_library(
     name = "type_traits",
diff --git a/third_party/abseil_cpp/absl/meta/type_traits.h b/third_party/abseil_cpp/absl/meta/type_traits.h
index ba87d2f0edfa..d5cb5f3be39d 100644
--- a/third_party/abseil_cpp/absl/meta/type_traits.h
+++ b/third_party/abseil_cpp/absl/meta/type_traits.h
@@ -219,7 +219,7 @@ using void_t = typename type_traits_internal::VoidTImpl<Ts...>::type;
 // This metafunction is designed to be a drop-in replacement for the C++17
 // `std::conjunction` metafunction.
 template <typename... Ts>
-struct conjunction;
+struct conjunction : std::true_type {};
 
 template <typename T, typename... Ts>
 struct conjunction<T, Ts...>
@@ -228,9 +228,6 @@ struct conjunction<T, Ts...>
 template <typename T>
 struct conjunction<T> : T {};
 
-template <>
-struct conjunction<> : std::true_type {};
-
 // disjunction
 //
 // Performs a compile-time logical OR operation on the passed types (which
@@ -241,7 +238,7 @@ struct conjunction<> : std::true_type {};
 // This metafunction is designed to be a drop-in replacement for the C++17
 // `std::disjunction` metafunction.
 template <typename... Ts>
-struct disjunction;
+struct disjunction : std::false_type {};
 
 template <typename T, typename... Ts>
 struct disjunction<T, Ts...> :
@@ -250,9 +247,6 @@ struct disjunction<T, Ts...> :
 template <typename T>
 struct disjunction<T> : T {};
 
-template <>
-struct disjunction<> : std::false_type {};
-
 // negation
 //
 // Performs a compile-time logical NOT operation on the passed type (which
@@ -616,8 +610,22 @@ using common_type_t = typename std::common_type<T...>::type;
 template <typename T>
 using underlying_type_t = typename std::underlying_type<T>::type;
 
-template <typename T>
-using result_of_t = typename std::result_of<T>::type;
+
+namespace type_traits_internal {
+
+#if __cplusplus >= 201703L
+// std::result_of is deprecated (C++17) or removed (C++20)
+template<typename> struct result_of;
+template<typename F, typename... Args>
+struct result_of<F(Args...)> : std::invoke_result<F, Args...> {};
+#else
+template<typename F> using result_of = std::result_of<F>;
+#endif
+
+}  // namespace type_traits_internal
+
+template<typename F>
+using result_of_t = typename type_traits_internal::result_of<F>::type;
 
 namespace type_traits_internal {
 // In MSVC we can't probe std::hash or stdext::hash because it triggers a
-- 
cgit 1.4.1