Implement deduction guides for <array>; Reviewed as https://reviews.llvm.org/D46964

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@332768 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/containers/sequences/array/array.cons/deduct.fail.cpp

@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+// UNSUPPORTED: libcpp-no-deduction-guides
+
+
+// template <class T, class... U>
+//   array(T, U...) -> array<T, 1 + sizeof...(U)>;
+//
+//  Requires: (is_same_v<T, U> && ...) is true. Otherwise the program is ill-formed.
+
+
+#include <array>
+#include <cassert>
+#include <cstddef>
+
+#include "test_macros.h"
+
+int main()
+{
+    {
+    std::array arr{1,2,3L}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'array'}}
+    }
+}