Avoid instantiating discard_iterator while parsing

Author: bernhardmgruber

cub/cub/util_type.cuh

@@ -46,12 +46,12 @@
 #include <cub/detail/type_traits.cuh>
 #include <cub/detail/uninitialized_copy.cuh>
 
-#include <thrust/iterator/discard_iterator.h>
+#include <thrust/iterator/detail/any_assign.h>
 
 #include <cuda/std/cstdint>
 #include <cuda/std/iterator>
 #include <cuda/std/limits>
-#include <cuda/std/type_traits>
+#include <cuda/type_traits>
 
 #if _CCCL_HAS_NVFP16()
 #  include <cuda_fp16.h>
@@ -113,11 +113,11 @@ struct non_void_value_impl
 template <typename It, typename FallbackT>
 struct non_void_value_impl<It, FallbackT, false>
 {
-  // we consider thrust::discard_iterator's value_type as `void` as well, so users can switch from
+  // we consider thrust::discard_iterator's value_type (`any_assign`) as `void` as well, so users can switch from
   // cub::DiscardInputIterator to thrust::discard_iterator.
   using type =
     ::cuda::std::_If<::cuda::std::is_void_v<it_value_t<It>>
-                       || ::cuda::std::is_same_v<it_value_t<It>, THRUST_NS_QUALIFIER::discard_iterator<>::value_type>,
+                       || ::cuda::std::is_same_v<it_value_t<It>, THRUST_NS_QUALIFIER::detail::any_assign>,
                      FallbackT,
                      it_value_t<It>>;
 };

thrust/thrust/iterator/discard_iterator.h

@@ -164,10 +164,11 @@ class discard_iterator : public detail::make_discard_iterator_base<System>::type
 //! parameter is \c 0.
 //! \return A new \p discard_iterator with index as given by \p i.
 //! \see constant_iterator
+template <typename System = use_default>
 inline _CCCL_HOST_DEVICE discard_iterator<>
-make_discard_iterator(discard_iterator<>::difference_type i = discard_iterator<>::difference_type(0))
+make_discard_iterator(typename discard_iterator<System>::difference_type i = {})
 {
-  return discard_iterator<>(i);
+  return discard_iterator<System>(i);
 }
 
 //! \} // end fancyiterators