Fix the polymorphic adaptor to actually use its template parameter.

Github NVIDIA#968

Author: griwes

.gitignore

@@ -3,3 +3,4 @@ thrust/system/cuda/detail/.gitignore
 run
 build
 doc/html
+discrete_voronoi.pgm

examples/mr_basic.cu

@@ -2,6 +2,8 @@
 #include <thrust/mr/new.h>
 #include <thrust/mr/pool.h>
 #include <thrust/mr/disjoint_pool.h>
+#include <thrust/device_vector.h>
+#include <thrust/device_ptr.h>
 
 #include <cassert>
 
@@ -43,6 +45,18 @@ int main()
         do_stuff_with_vector<thrust::host_vector<int, Alloc> >(alloc);
     }
 
+    {
+        // use the global device_ptr-flavored device memory resource
+        typedef thrust::device_ptr_memory_resource<thrust::device_memory_resource> Resource;
+        thrust::mr::polymorphic_adaptor_resource<thrust::device_ptr<void> > adaptor(
+            thrust::mr::get_global_resource<Resource>()
+        );
+        typedef thrust::mr::polymorphic_allocator<int, thrust::device_ptr<void> > Alloc;
+        Alloc alloc(&adaptor);
+
+        do_stuff_with_vector<thrust::device_vector<int, Alloc> >(alloc);
+    }
+
     typedef thrust::mr::unsynchronized_pool_resource<
         thrust::mr::new_delete_resource
     > Pool;

thrust/mr/polymorphic_adaptor.h

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2018 NVIDIA Corporation
+ *  Copyright 2018-2019 NVIDIA Corporation
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -31,12 +31,12 @@ class polymorphic_adaptor_resource THRUST_FINAL : public memory_resource<Pointer
     {
     }
 
-    virtual void * do_allocate(std::size_t bytes, std::size_t alignment = THRUST_MR_DEFAULT_ALIGNMENT) THRUST_OVERRIDE
+    virtual Pointer do_allocate(std::size_t bytes, std::size_t alignment = THRUST_MR_DEFAULT_ALIGNMENT) THRUST_OVERRIDE
     {
         return upstream_resource->allocate(bytes, alignment);
     }
 
-    virtual void do_deallocate(void * p, std::size_t bytes, std::size_t alignment) THRUST_OVERRIDE
+    virtual void do_deallocate(Pointer p, std::size_t bytes, std::size_t alignment) THRUST_OVERRIDE
     {
         return upstream_resource->deallocate(p, bytes, alignment);
     }