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-rw-r--r--absl/utility/utility.h26
1 files changed, 24 insertions, 2 deletions
diff --git a/absl/utility/utility.h b/absl/utility/utility.h
index 853c1fb8..7686db12 100644
--- a/absl/utility/utility.h
+++ b/absl/utility/utility.h
@@ -113,6 +113,20 @@ struct Gen<T, 0> {
using type = integer_sequence<T>;
};
+template <typename T>
+struct InPlaceTypeTag {
+ explicit InPlaceTypeTag() = delete;
+ InPlaceTypeTag(const InPlaceTypeTag&) = delete;
+ InPlaceTypeTag& operator=(const InPlaceTypeTag&) = delete;
+};
+
+template <size_t I>
+struct InPlaceIndexTag {
+ explicit InPlaceIndexTag() = delete;
+ InPlaceIndexTag(const InPlaceIndexTag&) = delete;
+ InPlaceIndexTag& operator=(const InPlaceIndexTag&) = delete;
+};
+
} // namespace utility_internal
// Compile-time sequences of integers
@@ -162,6 +176,7 @@ ABSL_INTERNAL_INLINE_CONSTEXPR(in_place_t, in_place, {});
#endif // ABSL_HAVE_STD_OPTIONAL
#if defined(ABSL_HAVE_STD_ANY) || defined(ABSL_HAVE_STD_VARIANT)
+using std::in_place_type;
using std::in_place_type_t;
#else
@@ -171,10 +186,14 @@ using std::in_place_type_t;
// be specified, such as with `absl::any`, designed to be a drop-in replacement
// for C++17's `std::in_place_type_t`.
template <typename T>
-struct in_place_type_t {};
+using in_place_type_t = void (*)(utility_internal::InPlaceTypeTag<T>);
+
+template <typename T>
+void in_place_type(utility_internal::InPlaceTypeTag<T>) {}
#endif // ABSL_HAVE_STD_ANY || ABSL_HAVE_STD_VARIANT
#ifdef ABSL_HAVE_STD_VARIANT
+using std::in_place_index;
using std::in_place_index_t;
#else
@@ -184,7 +203,10 @@ using std::in_place_index_t;
// be specified, such as with `absl::any`, designed to be a drop-in replacement
// for C++17's `std::in_place_index_t`.
template <size_t I>
-struct in_place_index_t {};
+using in_place_index_t = void (*)(utility_internal::InPlaceIndexTag<I>);
+
+template <size_t I>
+void in_place_index(utility_internal::InPlaceIndexTag<I>) {}
#endif // ABSL_HAVE_STD_VARIANT
// Constexpr move and forward