Add deduction guides for optional
llvm-svn: 333251
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: f35b4bc3954f3b01051fc0848535ff784809e9e2
diff --git a/include/optional b/include/optional
index 1f8e491..a76f8d1 100644
--- a/include/optional
+++ b/include/optional
@@ -139,6 +139,10 @@
private:
T *val; // exposition only
};
+
+template<class T>
+ optional(T) -> optional<T>;
+
} // namespace std
*/
@@ -1003,6 +1007,11 @@
}
};
+#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
+template<class T>
+ optional(T) -> optional<T>;
+#endif
+
// Comparisons between optionals
template <class _Tp, class _Up>
_LIBCPP_INLINE_VISIBILITY constexpr
diff --git a/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp b/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp
new file mode 100644
index 0000000..4ebafad
--- /dev/null
+++ b/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <optional>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// UNSUPPORTED: libcpp-no-deduction-guides
+
+
+// template<class T>
+// optional(T) -> optional<T>;
+
+
+#include <optional>
+#include <cassert>
+
+struct A {};
+
+int main()
+{
+// Test the explicit deduction guides
+
+// Test the implicit deduction guides
+ {
+// optional()
+ std::optional opt; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'optional'}}
+ }
+
+ {
+// optional(nullopt_t)
+ std::optional opt(std::nullopt); // expected-error-re@optional:* {{static_assert failed{{.*}} "instantiation of optional with nullopt_t is ill-formed"}}
+ }
+}
diff --git a/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp b/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp
new file mode 100644
index 0000000..1ef7a3a
--- /dev/null
+++ b/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp
@@ -0,0 +1,44 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <optional>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// UNSUPPORTED: libcpp-no-deduction-guides
+
+
+// template<class T>
+// optional(T) -> optional<T>;
+
+
+#include <optional>
+#include <cassert>
+
+struct A {};
+
+int main()
+{
+// Test the explicit deduction guides
+ {
+// optional(T)
+ std::optional opt(5);
+ static_assert(std::is_same_v<decltype(opt), std::optional<int>>, "");
+ assert(static_cast<bool>(opt));
+ assert(*opt == 5);
+ }
+
+ {
+// optional(T)
+ std::optional opt(A{});
+ static_assert(std::is_same_v<decltype(opt), std::optional<A>>, "");
+ assert(static_cast<bool>(opt));
+ }
+
+// Test the implicit deduction guides
+
+}