Correct unused parameter warnings in dictonary algorithms (#8239)

Starting in CUDA 11.3, nvcc will start to unconditionally warn about unused parameters on functions/methods that are in anonymous namespaces.

Authors:
  - Robert Maynard (https://github.com/robertmaynard)

Approvers:
  - David Wendt (https://github.com/davidwendt)
  - Karthikeyan (https://github.com/karthikeyann)

URL: #8239

cpp/src/dictionary/detail/concatenate.cu

@@ -169,18 +169,12 @@ struct dispatch_compute_indices {
     return result;
   }
 
-  template <typename Element>
+  template <typename Element, typename... Args>
   typename std::enable_if_t<!cudf::is_relationally_comparable<Element, Element>(),
                             std::unique_ptr<column>>
-  operator()(column_view const&,
-             column_view const&,
-             column_view const&,
-             offsets_pair const*,
-             size_type const*,
-             rmm::cuda_stream_view stream,
-             rmm::mr::device_memory_resource*)
+  operator()(Args&&...)
   {
-    CUDF_FAIL("list_view as keys for dictionary not supported");
+    CUDF_FAIL("dictionary concatenate not supported for this column type");
   }
 };
 

cpp/src/dictionary/search.cu

@@ -45,7 +45,7 @@ struct dispatch_scalar_index {
   template <typename IndexType,
             typename... Args,
             std::enable_if_t<not is_index_type<IndexType>()>* = nullptr>
-  std::unique_ptr<scalar> operator()(Args&&... args)
+  std::unique_ptr<scalar> operator()(Args&&...)
   {
     CUDF_FAIL("indices must be an integral type");
   }
@@ -89,33 +89,18 @@ struct find_index_fn {
                            stream,
                            mr);
   }
-  template <typename Element,
-            std::enable_if_t<std::is_same<Element, dictionary32>::value>* = nullptr>
-  std::unique_ptr<scalar> operator()(dictionary_column_view const& input,
-                                     scalar const& key,
-                                     rmm::cuda_stream_view stream,
-                                     rmm::mr::device_memory_resource* mr) const
-  {
-    CUDF_FAIL("dictionary column cannot be the keys column of another dictionary");
-  }
-
-  template <typename Element, std::enable_if_t<std::is_same<Element, list_view>::value>* = nullptr>
-  std::unique_ptr<scalar> operator()(dictionary_column_view const& input,
-                                     scalar const& key,
-                                     rmm::cuda_stream_view stream,
-                                     rmm::mr::device_memory_resource* mr) const
-  {
-    CUDF_FAIL("list_view column cannot be the keys column of a dictionary");
-  }
 
   template <typename Element,
-            std::enable_if_t<std::is_same<Element, struct_view>::value>* = nullptr>
-  std::unique_ptr<scalar> operator()(dictionary_column_view const& input,
-                                     scalar const& key,
-                                     rmm::cuda_stream_view stream,
-                                     rmm::mr::device_memory_resource* mr) const
+            std::enable_if_t<std::is_same<Element, dictionary32>::value or
+                             std::is_same<Element, list_view>::value or
+                             std::is_same<Element, struct_view>::value>* = nullptr>
+  std::unique_ptr<scalar> operator()(dictionary_column_view const&,
+                                     scalar const&,
+                                     rmm::cuda_stream_view,
+                                     rmm::mr::device_memory_resource*) const
   {
-    CUDF_FAIL("struct_view column cannot be the keys column of a dictionary");
+    CUDF_FAIL(
+      "dictionary, list_view, and struct_view columns cannot be the keys column of a dictionary");
   }
 };
 
@@ -151,12 +136,12 @@ struct find_insert_index_fn {
             std::enable_if_t<std::is_same<Element, dictionary32>::value or
                              std::is_same<Element, list_view>::value or
                              std::is_same<Element, struct_view>::value>* = nullptr>
-  std::unique_ptr<scalar> operator()(dictionary_column_view const& input,
-                                     scalar const& key,
-                                     rmm::cuda_stream_view stream,
-                                     rmm::mr::device_memory_resource* mr) const
+  std::unique_ptr<scalar> operator()(dictionary_column_view const&,
+                                     scalar const&,
+                                     rmm::cuda_stream_view,
+                                     rmm::mr::device_memory_resource*) const
   {
-    CUDF_FAIL("column cannot be the keys for dictionary");
+    CUDF_FAIL("dictionary, list_view, and struct_view columns cannot be the keys for a dictionary");
   }
 };
 

cpp/src/dictionary/set_keys.cu

@@ -85,15 +85,12 @@ struct dispatch_compute_indices {
     return result;
   }
 
-  template <typename Element>
+  template <typename Element, typename... Args>
   typename std::enable_if_t<!cudf::is_relationally_comparable<Element, Element>(),
                             std::unique_ptr<column>>
-  operator()(dictionary_column_view const& input,
-             column_view const& new_keys,
-             rmm::cuda_stream_view stream,
-             rmm::mr::device_memory_resource* mr)
+  operator()(Args&&...)
   {
-    CUDF_FAIL("list_view dictionary set_keys not supported yet");
+    CUDF_FAIL("dictionary set_keys not supported for this column type");
   }
 };