libstdc++: Add a move-only testsuite iterator type

This adds a move-only testsuite iterator wrapper to <testsuite_iterators.h>
which will be used in the tests for LWG 3355.  The tests for LWG 3389 and 3390
are adjusted to use this new iterator wrapper.

libstdc++-v3/ChangeLog:

	* testsuite/util/testsuite_iterators.h (input_iterator_wrapper_nocopy):
	New testsuite iterator.
	* testsuite/24_iterators/counted_iterator/lwg3389.cc: Use it.
	* testsuite/24_iterators/move_iterator/lwg3390.cc: Likewise.

libstdc++-v3/ChangeLog

 2020-03-04  Patrick Palka  <ppalka@redhat.com>
 
+	* testsuite/util/testsuite_iterators.h (input_iterator_wrapper_nocopy):
+	New testsuite iterator.
+	* testsuite/24_iterators/counted_iterator/lwg3389.cc: use it.
+	* testsuite/24_iterators/move_iterator/lwg3390.cc: Likewise.
+
 	* include/bits/ranges_uninitialized.h
 	(uninitialized_copy_fn::operator()): Pass a reference type as the first
 	argument to is_nothrow_assignable_v.

libstdc++-v3/testsuite/24_iterators/counted_iterator/lwg3389.cc

@@ -23,44 +23,13 @@
 #include <testsuite_iterators.h>
 
 using __gnu_test::test_range;
-using __gnu_test::input_iterator_wrapper;
-
-template<typename T>
-struct move_only_wrapper : input_iterator_wrapper<T>
-{
-  using input_iterator_wrapper<T>::input_iterator_wrapper;
-
-  move_only_wrapper()
-    : input_iterator_wrapper<T>(nullptr, nullptr)
-  { }
-
-  move_only_wrapper(const move_only_wrapper&) = delete;
-  move_only_wrapper&
-  operator=(const move_only_wrapper&) = delete;
-
-  move_only_wrapper(move_only_wrapper&&) = default;
-  move_only_wrapper&
-  operator=(move_only_wrapper&&) = default;
-
-  using input_iterator_wrapper<T>::operator++;
-
-  move_only_wrapper&
-  operator++()
-  {
-    input_iterator_wrapper<T>::operator++();
-    return *this;
-  }
-};
-
-static_assert(std::input_iterator<move_only_wrapper<int>>);
-static_assert(!std::forward_iterator<move_only_wrapper<int>>);
-static_assert(!std::copyable<move_only_wrapper<int>>);
+using __gnu_test::input_iterator_wrapper_nocopy;
 
 // LWG 3389
 void
 test01()
 {
   int x[] = {1,2,3,4};
-  test_range<int, move_only_wrapper> rx(x);
+  test_range<int, input_iterator_wrapper_nocopy> rx(x);
   auto it = std::counted_iterator(rx.begin(), 2);
 }

libstdc++-v3/testsuite/24_iterators/move_iterator/lwg3390.cc

@@ -23,44 +23,13 @@
 #include <testsuite_iterators.h>
 
 using __gnu_test::test_range;
-using __gnu_test::input_iterator_wrapper;
-
-template<typename T>
-struct move_only_wrapper : input_iterator_wrapper<T>
-{
-  using input_iterator_wrapper<T>::input_iterator_wrapper;
-
-  move_only_wrapper()
-    : input_iterator_wrapper<T>(nullptr, nullptr)
-  { }
-
-  move_only_wrapper(const move_only_wrapper&) = delete;
-  move_only_wrapper&
-  operator=(const move_only_wrapper&) = delete;
-
-  move_only_wrapper(move_only_wrapper&&) = default;
-  move_only_wrapper&
-  operator=(move_only_wrapper&&) = default;
-
-  using input_iterator_wrapper<T>::operator++;
-
-  move_only_wrapper&
-  operator++()
-  {
-    input_iterator_wrapper<T>::operator++();
-    return *this;
-  }
-};
-
-static_assert(std::input_iterator<move_only_wrapper<int>>);
-static_assert(!std::forward_iterator<move_only_wrapper<int>>);
-static_assert(!std::copyable<move_only_wrapper<int>>);
+using __gnu_test::input_iterator_wrapper_nocopy;
 
 // LWG 3390
 void
 test01()
 {
   int x[] = {1,2,3,4};
-  test_range<int, move_only_wrapper> rx(x);
+  test_range<int, input_iterator_wrapper_nocopy> rx(x);
   auto it = std::make_move_iterator(rx.begin());
 }

libstdc++-v3/testsuite/util/testsuite_iterators.h

@@ -674,6 +674,34 @@ namespace __gnu_test
       { return iter -= n; }
     };
 
+  // A move-only input iterator type.
+  template<typename T>
+    struct input_iterator_wrapper_nocopy : input_iterator_wrapper<T>
+    {
+      using input_iterator_wrapper<T>::input_iterator_wrapper;
+
+      input_iterator_wrapper_nocopy()
+	: input_iterator_wrapper<T>(nullptr, nullptr)
+      { }
+
+      input_iterator_wrapper_nocopy(const input_iterator_wrapper_nocopy&) = delete;
+      input_iterator_wrapper_nocopy&
+      operator=(const input_iterator_wrapper_nocopy&) = delete;
+
+      input_iterator_wrapper_nocopy(input_iterator_wrapper_nocopy&&) = default;
+      input_iterator_wrapper_nocopy&
+      operator=(input_iterator_wrapper_nocopy&&) = default;
+
+      using input_iterator_wrapper<T>::operator++;
+
+      input_iterator_wrapper_nocopy&
+      operator++()
+      {
+	input_iterator_wrapper<T>::operator++();
+	return *this;
+      }
+    };
+
   // A type meeting the minimum std::range requirements
   template<typename T, template<typename> class Iter>
     class test_range