The bind and function functor constructors and assignment operators were overly general and getting confused with the copy constructor and copy assignment operators. Constrained them. This fixes http://llvm.org/bugs/show_bug.cgi?id=16385

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@185297 91177308-0d34-0410-b5e6-96231b3b80d8

test/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp

@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <functional>
+
+// template<CopyConstructible Fn, CopyConstructible... Types>
+//   unspecified bind(Fn, Types...);
+// template<Returnable R, CopyConstructible Fn, CopyConstructible... Types>
+//   unspecified bind(Fn, Types...);
+
+// http://llvm.org/bugs/show_bug.cgi?id=16385
+
+#include <functional>
+#include <cmath>
+#include <cassert>
+
+float _pow(float a, float b)
+{
+    return std::pow(a, b);
+}
+
+int main()
+{
+    std::function<float(float, float)> fnc = _pow;
+    auto task = std::bind(fnc, 2.f, 4.f);
+    auto task2(task);
+    assert(task() == 16);
+    assert(task2() == 16);
+}