2 files changed, 22 insertions, 29 deletions
diff --git a/absl/types/internal/variant.h b/absl/types/internal/variant.h
index 94c2ddab6fcb..3414c9142daf 100644
--- a/absl/types/internal/variant.h
+++ b/absl/types/internal/variant.h
@@ -1100,49 +1100,40 @@ using EqualResult = decltype(std::declval<T>() == std::declval<T>());
 template <class T>
 using NotEqualResult = decltype(std::declval<T>() != std::declval<T>());
 
-template <class T>
-using HasLessThan = is_detected_convertible<bool, LessThanResult, T>;
-
-template <class T>
-using HasGreaterThan = is_detected_convertible<bool, GreaterThanResult, T>;
-
-template <class T>
-using HasLessThanOrEqual =
-    is_detected_convertible<bool, LessThanOrEqualResult, T>;
-
-template <class T>
-using HasGreaterThanOrEqual =
-    is_detected_convertible<bool, GreaterThanOrEqualResult, T>;
-
-template <class T>
-using HasEqual = is_detected_convertible<bool, EqualResult, T>;
-
-template <class T>
-using HasNotEqual = is_detected_convertible<bool, NotEqualResult, T>;
-
 template <class... T>
-using RequireAllHaveEqualT =
-    absl::enable_if_t<absl::conjunction<HasEqual<T>...>::value, bool>;
+using RequireAllHaveEqualT = absl::enable_if_t<
+    absl::conjunction<is_detected_convertible<bool, EqualResult, T>...>::value,
+    bool>;
 
 template <class... T>
 using RequireAllHaveNotEqualT =
-    absl::enable_if_t<absl::conjunction<HasEqual<T>...>::value, bool>;
+    absl::enable_if_t<absl::conjunction<is_detected_convertible<
+                          bool, NotEqualResult, T>...>::value,
+                      bool>;
 
 template <class... T>
 using RequireAllHaveLessThanT =
-    absl::enable_if_t<absl::conjunction<HasLessThan<T>...>::value, bool>;
+    absl::enable_if_t<absl::conjunction<is_detected_convertible<
+                          bool, LessThanResult, T>...>::value,
+                      bool>;
 
 template <class... T>
 using RequireAllHaveLessThanOrEqualT =
-    absl::enable_if_t<absl::conjunction<HasLessThan<T>...>::value, bool>;
+    absl::enable_if_t<absl::conjunction<is_detected_convertible<
+                          bool, LessThanOrEqualResult, T>...>::value,
+                      bool>;
 
 template <class... T>
 using RequireAllHaveGreaterThanOrEqualT =
-    absl::enable_if_t<absl::conjunction<HasLessThan<T>...>::value, bool>;
+    absl::enable_if_t<absl::conjunction<is_detected_convertible<
+                          bool, GreaterThanOrEqualResult, T>...>::value,
+                      bool>;
 
 template <class... T>
 using RequireAllHaveGreaterThanT =
-    absl::enable_if_t<absl::conjunction<HasLessThan<T>...>::value, bool>;
+    absl::enable_if_t<absl::conjunction<is_detected_convertible<
+                          bool, GreaterThanResult, T>...>::value,
+                      bool>;
 
 // Helper template containing implementations details of variant that can't go
 // in the private section. For convenience, this takes the variant type as a
diff --git a/absl/types/variant.h b/absl/types/variant.h
index 5837a1be2105..55017ae194b0 100644
--- a/absl/types/variant.h
+++ b/absl/types/variant.h
@@ -445,9 +445,11 @@ constexpr bool operator!=(monostate, monostate) noexcept { return false; }
 //------------------------------------------------------------------------------
 template <typename T0, typename... Tn>
 class variant<T0, Tn...> : private variant_internal::VariantBase<T0, Tn...> {
+  // Intentionally not qualifing `negation` with `absl::` to work around a bug
+  // in MSVC 2015 with inline namespace and variadic template.
   static_assert(absl::conjunction<std::is_object<T0>, std::is_object<Tn>...,
-                                  absl::negation<std::is_array<T0>>,
-                                  absl::negation<std::is_array<Tn>>...,
+                                  negation<std::is_array<T0> >,
+                                  negation<std::is_array<Tn> >...,
                                   std::is_nothrow_destructible<T0>,
                                   std::is_nothrow_destructible<Tn>...>::value,
                 "Attempted to instantiate a variant with an unsupported type.");