Add QtPrivate::ArrowProxy

... use it in QKeyValueIterator.

This is somewhat simpler than the old QKeyValueIterator::pointer.

I don't think the pointer::operator*() could have ever worked, because
it returns value_type&, but is const.

That leaves the defaulted copy and move SMFs as a difference (ArrowProxy
is using aggregate initialization, so doesn't need any), and the fact
that operator->() is const.

Change-Id: I80b9c5f696de6ae30f3939166b205b9213eac57e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/corelib/tools/qcontainertools_impl.h b/src/corelib/tools/qcontainertools_impl.h
index d66705ef4d..ef73a2a69f 100644
--- a/src/corelib/tools/qcontainertools_impl.h
+++ b/src/corelib/tools/qcontainertools_impl.h
@@ -254,6 +254,13 @@ void q_relocate_overlap_n(T *first, N n, T *d_first)
     }
 }
 
+template <typename T>
+struct ArrowProxy
+{
+    T t;
+    T *operator->() noexcept { return &t; }
+};
+
 template <typename Iterator>
 using IfIsInputIterator = typename std::enable_if<
     std::is_convertible<typename std::iterator_traits<Iterator>::iterator_category, std::input_iterator_tag>::value,