diff --git a/CMakeLists.txt b/CMakeLists.txt
index f3ca85a8a..25fb514d9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,6 +15,9 @@
 #=============================================================================
 cmake_minimum_required(VERSION 3.23.1 FATAL_ERROR)
 
+set(rapids-cmake-repo bdice/rapids-cmake)
+set(rapids-cmake-branch cccl-update-2.1.0)
+
 if(NOT EXISTS ${CMAKE_CURRENT_BINARY_DIR}/CUCO_RAPIDS.cmake)
     file(DOWNLOAD https://raw.githubusercontent.com/rapidsai/rapids-cmake/branch-23.10/RAPIDS.cmake
          ${CMAKE_CURRENT_BINARY_DIR}/CUCO_RAPIDS.cmake)
diff --git a/examples/static_map/custom_type_example.cu b/examples/static_map/custom_type_example.cu
index e150a858e..7430fda84 100644
--- a/examples/static_map/custom_type_example.cu
+++ b/examples/static_map/custom_type_example.cu
@@ -22,6 +22,8 @@
 #include <thrust/logical.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 // User-defined key type
 #if !defined(CUCO_HAS_INDEPENDENT_THREADS)
 struct custom_key_type {
@@ -88,7 +90,8 @@ int main(void)
   // Create an iterator of input key/value pairs
   auto pairs_begin = thrust::make_transform_iterator(
     thrust::make_counting_iterator<int32_t>(0),
-    [] __device__(auto i) { return cuco::make_pair(custom_key_type{i}, custom_value_type{i}); });
+    cuda::proclaim_return_type<cuco::pair<custom_key_type, custom_value_type>>(
+      [] __device__(auto i) { return cuco::make_pair(custom_key_type{i}, custom_value_type{i}); }));
 
   // Construct a map with 100,000 slots using the given empty key/value sentinels. Note the
   // capacity is chosen knowing we will insert 80,000 keys, for an load factor of 80%.
@@ -101,7 +104,8 @@ int main(void)
   // Reproduce inserted keys
   auto insert_keys =
     thrust::make_transform_iterator(thrust::make_counting_iterator<int32_t>(0),
-                                    [] __device__(auto i) { return custom_key_type{i}; });
+                                    cuda::proclaim_return_type<custom_key_type>(
+                                      [] __device__(auto i) { return custom_key_type{i}; }));
 
   thrust::device_vector<bool> contained(num_pairs);
 
@@ -114,7 +118,9 @@ int main(void)
 
   // All inserted keys are contained
   assert(
-    thrust::all_of(contained.begin(), contained.end(), [] __device__(auto const& b) { return b; }));
+    thrust::all_of(contained.begin(),
+                   contained.end(),
+                   cuda::proclaim_return_type<bool>([] __device__(auto const& b) { return b; })));
 
   return 0;
 }
diff --git a/tests/dynamic_map/unique_sequence_test.cu b/tests/dynamic_map/unique_sequence_test.cu
index aa01ca51a..d9364f341 100644
--- a/tests/dynamic_map/unique_sequence_test.cu
+++ b/tests/dynamic_map/unique_sequence_test.cu
@@ -27,6 +27,8 @@
 #include <thrust/sequence.h>
 #include <thrust/tuple.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
@@ -48,9 +50,10 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
   thrust::sequence(thrust::device, d_keys.begin(), d_keys.end());
   thrust::sequence(thrust::device, d_values.begin(), d_values.end());
 
-  auto pairs_begin =
-    thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
-                                    [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); });
+  auto pairs_begin = thrust::make_transform_iterator(
+    thrust::make_counting_iterator<int>(0),
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); }));
 
   thrust::device_vector<Value> d_results(num_keys);
   thrust::device_vector<bool> d_contained(num_keys);
@@ -62,9 +65,10 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
     map.find(d_keys.begin(), d_keys.end(), d_results.begin());
     auto zip = thrust::make_zip_iterator(thrust::make_tuple(d_results.begin(), d_values.begin()));
 
-    REQUIRE(cuco::test::all_of(zip, zip + num_keys, [] __device__(auto const& p) {
-      return thrust::get<0>(p) == thrust::get<1>(p);
-    }));
+    REQUIRE(cuco::test::all_of(
+      zip, zip + num_keys, cuda::proclaim_return_type<bool>([] __device__(auto const& p) {
+        return thrust::get<0>(p) == thrust::get<1>(p);
+      })));
   }
 
   SECTION("All non-inserted keys-value pairs should have the empty sentinel value recovered")
@@ -72,7 +76,9 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
     map.find(d_keys.begin(), d_keys.end(), d_results.begin());
 
     REQUIRE(cuco::test::all_of(
-      d_results.begin(), d_results.end(), [] __device__(auto const& p) { return p == -1; }));
+      d_results.begin(),
+      d_results.end(),
+      cuda::proclaim_return_type<bool>([] __device__(auto const& p) { return p == -1; })));
   }
 
   SECTION("All inserted keys-value pairs should be contained")
diff --git a/tests/static_map/custom_type_test.cu b/tests/static_map/custom_type_test.cu
index e23216ca3..fbba8ec3b 100644
--- a/tests/static_map/custom_type_test.cu
+++ b/tests/static_map/custom_type_test.cu
@@ -25,6 +25,8 @@
 #include <thrust/iterator/transform_iterator.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 #include <tuple>
@@ -123,17 +125,18 @@ TEMPLATE_TEST_CASE_SIG("User defined key and value type",
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num),
                     insert_keys.begin(),
-                    [] __device__(auto i) { return Key{i}; });
+                    cuda::proclaim_return_type<Key>([] __device__(auto i) { return Key{i}; }));
 
   thrust::transform(thrust::device,
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num),
                     insert_values.begin(),
-                    [] __device__(auto i) { return Value{i}; });
+                    cuda::proclaim_return_type<Value>([] __device__(auto i) { return Value{i}; }));
 
-  auto insert_pairs =
-    thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
-                                    [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); });
+  auto insert_pairs = thrust::make_transform_iterator(
+    thrust::make_counting_iterator<int>(0),
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); }));
 
   SECTION("All inserted keys-value pairs should be correctly recovered during find")
   {
@@ -151,9 +154,9 @@ TEMPLATE_TEST_CASE_SIG("User defined key and value type",
     REQUIRE(cuco::test::equal(insert_values.begin(),
                               insert_values.end(),
                               found_values.begin(),
-                              [] __device__(Value lhs, Value rhs) {
+                              cuda::proclaim_return_type<bool>([] __device__(Value lhs, Value rhs) {
                                 return std::tie(lhs.f, lhs.s) == std::tie(rhs.f, rhs.s);
-                              }));
+                              })));
   }
 
   SECTION("All inserted keys-value pairs should be contained")
@@ -175,7 +178,7 @@ TEMPLATE_TEST_CASE_SIG("User defined key and value type",
       insert_pairs,
       insert_pairs + num,
       thrust::counting_iterator<int>(0),
-      [] __device__(auto const& key) { return (key % 2) == 0; },
+      cuda::proclaim_return_type<bool>([] __device__(auto const& key) { return (key % 2) == 0; }),
       hash_custom_key{},
       custom_key_equals{});
 
@@ -187,12 +190,13 @@ TEMPLATE_TEST_CASE_SIG("User defined key and value type",
                  hash_custom_key{},
                  custom_key_equals{});
 
-    REQUIRE(cuco::test::equal(contained.begin(),
-                              contained.end(),
-                              thrust::counting_iterator<int>(0),
-                              [] __device__(auto const& idx_contained, auto const& idx) {
-                                return ((idx % 2) == 0) == idx_contained;
-                              }));
+    REQUIRE(cuco::test::equal(
+      contained.begin(),
+      contained.end(),
+      thrust::counting_iterator<int>(0),
+      cuda::proclaim_return_type<bool>([] __device__(auto const& idx_contained, auto const& idx) {
+        return ((idx % 2) == 0) == idx_contained;
+      })));
   }
 
   SECTION("Non-inserted keys-value pairs should not be contained")
@@ -212,9 +216,11 @@ TEMPLATE_TEST_CASE_SIG("User defined key and value type",
     map.insert(insert_pairs, insert_pairs + num, hash_custom_key{}, custom_key_equals{});
     auto view = map.get_device_view();
     REQUIRE(cuco::test::all_of(
-      insert_pairs, insert_pairs + num, [view] __device__(cuco::pair<Key, Value> const& pair) {
+      insert_pairs,
+      insert_pairs + num,
+      cuda::proclaim_return_type<bool>([view] __device__(cuco::pair<Key, Value> const& pair) {
         return view.contains(pair.first, hash_custom_key{}, custom_key_equals{});
-      }));
+      })));
   }
 
   SECTION("Inserting unique keys should return insert success.")
@@ -222,9 +228,11 @@ TEMPLATE_TEST_CASE_SIG("User defined key and value type",
     auto m_view = map.get_device_mutable_view();
     REQUIRE(cuco::test::all_of(insert_pairs,
                                insert_pairs + num,
-                               [m_view] __device__(cuco::pair<Key, Value> const& pair) mutable {
-                                 return m_view.insert(pair, hash_custom_key{}, custom_key_equals{});
-                               }));
+                               cuda::proclaim_return_type<bool>(
+                                 [m_view] __device__(cuco::pair<Key, Value> const& pair) mutable {
+                                   return m_view.insert(
+                                     pair, hash_custom_key{}, custom_key_equals{});
+                                 })));
   }
 
   SECTION("Cannot find any key in an empty hash map")
@@ -235,18 +243,21 @@ TEMPLATE_TEST_CASE_SIG("User defined key and value type",
       REQUIRE(cuco::test::all_of(
         insert_pairs,
         insert_pairs + num,
-        [view] __device__(cuco::pair<Key, Value> const& pair) mutable {
-          return view.find(pair.first, hash_custom_key{}, custom_key_equals{}) == view.end();
-        }));
+        cuda::proclaim_return_type<bool>(
+          [view] __device__(cuco::pair<Key, Value> const& pair) mutable {
+            return view.find(pair.first, hash_custom_key{}, custom_key_equals{}) == view.end();
+          })));
     }
 
     SECTION("const view")
     {
       auto const view = map.get_device_view();
       REQUIRE(cuco::test::all_of(
-        insert_pairs, insert_pairs + num, [view] __device__(cuco::pair<Key, Value> const& pair) {
+        insert_pairs,
+        insert_pairs + num,
+        cuda::proclaim_return_type<bool>([view] __device__(cuco::pair<Key, Value> const& pair) {
           return view.find(pair.first, hash_custom_key{}, custom_key_equals{}) == view.end();
-        }));
+        })));
     }
   }
 }
diff --git a/tests/static_map/duplicate_keys_test.cu b/tests/static_map/duplicate_keys_test.cu
index 5620fa4e9..64f9d35cf 100644
--- a/tests/static_map/duplicate_keys_test.cu
+++ b/tests/static_map/duplicate_keys_test.cu
@@ -27,6 +27,8 @@
 #include <thrust/sequence.h>
 #include <thrust/sort.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 TEMPLATE_TEST_CASE_SIG("Duplicate keys",
@@ -49,7 +51,8 @@ TEMPLATE_TEST_CASE_SIG("Duplicate keys",
 
   auto pairs_begin = thrust::make_transform_iterator(
     thrust::make_counting_iterator<int>(0),
-    [] __device__(auto i) { return cuco::pair<Key, Value>(i / 2, i / 2); });
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i / 2, i / 2); }));
 
   thrust::device_vector<Value> d_results(num_keys);
   thrust::device_vector<bool> d_contained(num_keys);
diff --git a/tests/static_map/heterogeneous_lookup_test.cu b/tests/static_map/heterogeneous_lookup_test.cu
index e842612b1..260dc34cb 100644
--- a/tests/static_map/heterogeneous_lookup_test.cu
+++ b/tests/static_map/heterogeneous_lookup_test.cu
@@ -25,6 +25,8 @@
 #include <thrust/iterator/transform_iterator.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 #include <tuple>
@@ -99,11 +101,13 @@ TEMPLATE_TEST_CASE("Heterogeneous lookup",
   cuco::static_map<Key, Value> map{
     capacity, cuco::empty_key<Key>{sentinel_key}, cuco::empty_value<Value>{sentinel_value}};
 
-  auto insert_pairs =
-    thrust::make_transform_iterator(thrust::counting_iterator<int>(0),
-                                    [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); });
-  auto probe_keys = thrust::make_transform_iterator(thrust::counting_iterator<int>(0),
-                                                    [] __device__(auto i) { return ProbeKey(i); });
+  auto insert_pairs = thrust::make_transform_iterator(
+    thrust::counting_iterator<int>(0),
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); }));
+  auto probe_keys = thrust::make_transform_iterator(
+    thrust::counting_iterator<int>(0),
+    cuda::proclaim_return_type<ProbeKey>([] __device__(auto i) { return ProbeKey(i); }));
 
   SECTION("All inserted keys-value pairs should be contained")
   {
diff --git a/tests/static_map/key_sentinel_test.cu b/tests/static_map/key_sentinel_test.cu
index 74a1badd1..349df62dd 100644
--- a/tests/static_map/key_sentinel_test.cu
+++ b/tests/static_map/key_sentinel_test.cu
@@ -22,6 +22,8 @@
 #include <thrust/iterator/counting_iterator.h>
 #include <thrust/iterator/transform_iterator.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 #define SIZE 10
@@ -51,19 +53,21 @@ TEMPLATE_TEST_CASE_SIG(
   }
   CUCO_CUDA_TRY(cudaMemcpyToSymbol(A, h_A, SIZE * sizeof(int)));
 
-  auto pairs_begin =
-    thrust::make_transform_iterator(thrust::make_counting_iterator<T>(0),
-                                    [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); });
+  auto pairs_begin = thrust::make_transform_iterator(
+    thrust::make_counting_iterator<T>(0),
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); }));
 
   SECTION(
     "Tests of non-CG insert: The custom `key_equal` can never be used to compare against sentinel")
   {
-    REQUIRE(cuco::test::all_of(pairs_begin,
-                               pairs_begin + num_keys,
-                               [m_view] __device__(cuco::pair<Key, Value> const& pair) mutable {
-                                 return m_view.insert(
-                                   pair, cuco::default_hash_function<Key>{}, custom_equals<Key>{});
-                               }));
+    REQUIRE(cuco::test::all_of(
+      pairs_begin,
+      pairs_begin + num_keys,
+      cuda::proclaim_return_type<bool>(
+        [m_view] __device__(cuco::pair<Key, Value> const& pair) mutable {
+          return m_view.insert(pair, cuco::default_hash_function<Key>{}, custom_equals<Key>{});
+        })));
   }
 
   SECTION(
@@ -75,10 +79,12 @@ TEMPLATE_TEST_CASE_SIG(
                custom_equals<Key>{});
     // All keys inserted via custom `key_equal` should be found
     REQUIRE(cuco::test::all_of(
-      pairs_begin, pairs_begin + num_keys, [view] __device__(cuco::pair<Key, Value> const& pair) {
+      pairs_begin,
+      pairs_begin + num_keys,
+      cuda::proclaim_return_type<bool>([view] __device__(cuco::pair<Key, Value> const& pair) {
         auto const found = view.find(pair.first);
         return (found != view.end()) and
                (found->first.load() == pair.first and found->second.load() == pair.second);
-      }));
+      })));
   }
 }
diff --git a/tests/static_map/shared_memory_test.cu b/tests/static_map/shared_memory_test.cu
index 444f1c7e7..351ef9f6a 100644
--- a/tests/static_map/shared_memory_test.cu
+++ b/tests/static_map/shared_memory_test.cu
@@ -25,6 +25,8 @@
 #include <thrust/sequence.h>
 #include <thrust/tuple.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 #include <limits>
@@ -127,9 +129,11 @@ TEMPLATE_TEST_CASE_SIG("Shared memory static map",
     auto zip = thrust::make_zip_iterator(
       thrust::make_tuple(d_keys_exist.begin(), d_keys_and_values_correct.begin()));
 
-    REQUIRE(cuco::test::all_of(zip, zip + d_keys_exist.size(), [] __device__(auto const& z) {
-      return thrust::get<0>(z) and thrust::get<1>(z);
-    }));
+    REQUIRE(cuco::test::all_of(zip,
+                               zip + d_keys_exist.size(),
+                               cuda::proclaim_return_type<bool>([] __device__(auto const& z) {
+                                 return thrust::get<0>(z) and thrust::get<1>(z);
+                               })));
   }
 
   SECTION("No key is found before insertion.")
diff --git a/tests/static_map/stream_test.cu b/tests/static_map/stream_test.cu
index 6121cbd62..7344ab785 100644
--- a/tests/static_map/stream_test.cu
+++ b/tests/static_map/stream_test.cu
@@ -27,6 +27,8 @@
 #include <thrust/sequence.h>
 #include <thrust/tuple.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 TEMPLATE_TEST_CASE_SIG("Unique sequence of keys on given stream",
@@ -53,9 +55,10 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys on given stream",
   thrust::sequence(thrust::device, d_keys.begin(), d_keys.end());
   thrust::sequence(thrust::device, d_values.begin(), d_values.end());
 
-  auto pairs_begin =
-    thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
-                                    [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); });
+  auto pairs_begin = thrust::make_transform_iterator(
+    thrust::make_counting_iterator<int>(0),
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); }));
 
   auto hash_fn  = cuco::default_hash_function<Key>{};
   auto equal_fn = thrust::equal_to<Value>{};
@@ -69,11 +72,12 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys on given stream",
     map.find(d_keys.begin(), d_keys.end(), d_results.begin(), hash_fn, equal_fn, stream);
     auto zip = thrust::make_zip_iterator(thrust::make_tuple(d_results.begin(), d_values.begin()));
 
-    REQUIRE(cuco::test::all_of(
-      zip,
-      zip + num_keys,
-      [] __device__(auto const& p) { return thrust::get<0>(p) == thrust::get<1>(p); },
-      stream));
+    REQUIRE(cuco::test::all_of(zip,
+                               zip + num_keys,
+                               cuda::proclaim_return_type<bool>([] __device__(auto const& p) {
+                                 return thrust::get<0>(p) == thrust::get<1>(p);
+                               }),
+                               stream));
   }
 
   SECTION("All inserted keys-value pairs should be contained")
diff --git a/tests/static_map/unique_sequence_test.cu b/tests/static_map/unique_sequence_test.cu
index 6a0165cc2..0cc8c8fc5 100644
--- a/tests/static_map/unique_sequence_test.cu
+++ b/tests/static_map/unique_sequence_test.cu
@@ -29,6 +29,8 @@
 #include <thrust/sort.h>
 #include <thrust/tuple.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
@@ -52,9 +54,10 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
   thrust::sequence(thrust::device, d_keys.begin(), d_keys.end());
   thrust::sequence(thrust::device, d_values.begin(), d_values.end());
 
-  auto pairs_begin =
-    thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
-                                    [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); });
+  auto pairs_begin = thrust::make_transform_iterator(
+    thrust::make_counting_iterator<int>(0),
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); }));
 
   thrust::device_vector<Value> d_results(num_keys);
   thrust::device_vector<bool> d_contained(num_keys);
@@ -66,9 +69,10 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
     map.find(d_keys.begin(), d_keys.end(), d_results.begin());
     auto zip = thrust::make_zip_iterator(thrust::make_tuple(d_results.begin(), d_values.begin()));
 
-    REQUIRE(cuco::test::all_of(zip, zip + num_keys, [] __device__(auto const& p) {
-      return thrust::get<0>(p) == thrust::get<1>(p);
-    }));
+    REQUIRE(cuco::test::all_of(
+      zip, zip + num_keys, cuda::proclaim_return_type<bool>([] __device__(auto const& p) {
+        return thrust::get<0>(p) == thrust::get<1>(p);
+      })));
   }
 
   SECTION("All inserted keys-value pairs should be contained")
@@ -90,9 +94,10 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
   {
     REQUIRE(cuco::test::all_of(pairs_begin,
                                pairs_begin + num_keys,
-                               [m_view] __device__(cuco::pair<Key, Value> const& pair) mutable {
-                                 return m_view.insert(pair);
-                               }));
+                               cuda::proclaim_return_type<bool>(
+                                 [m_view] __device__(cuco::pair<Key, Value> const& pair) mutable {
+                                   return m_view.insert(pair);
+                                 })));
   }
 
   SECTION("Cannot find any key in an empty hash map with non-const view")
@@ -101,16 +106,19 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
     {
       REQUIRE(cuco::test::all_of(pairs_begin,
                                  pairs_begin + num_keys,
-                                 [view] __device__(cuco::pair<Key, Value> const& pair) mutable {
-                                   return view.find(pair.first) == view.end();
-                                 }));
+                                 cuda::proclaim_return_type<bool>(
+                                   [view] __device__(cuco::pair<Key, Value> const& pair) mutable {
+                                     return view.find(pair.first) == view.end();
+                                   })));
     }
     SECTION("const view")
     {
       REQUIRE(cuco::test::all_of(
-        pairs_begin, pairs_begin + num_keys, [view] __device__(cuco::pair<Key, Value> const& pair) {
+        pairs_begin,
+        pairs_begin + num_keys,
+        cuda::proclaim_return_type<bool>([view] __device__(cuco::pair<Key, Value> const& pair) {
           return view.find(pair.first) == view.end();
-        }));
+        })));
     }
   }
 
@@ -121,29 +129,33 @@ TEMPLATE_TEST_CASE_SIG("Unique sequence of keys",
       thrust::device,
       pairs_begin,
       pairs_begin + num_keys,
-      [m_view] __device__(cuco::pair<Key, Value> const& pair) mutable { m_view.insert(pair); });
+      cuda::proclaim_return_type<void>(
+        [m_view] __device__(cuco::pair<Key, Value> const& pair) mutable { m_view.insert(pair); }));
 
     SECTION("non-const view")
     {
       // All keys should be found
       REQUIRE(cuco::test::all_of(pairs_begin,
                                  pairs_begin + num_keys,
-                                 [view] __device__(cuco::pair<Key, Value> const& pair) mutable {
-                                   auto const found = view.find(pair.first);
-                                   return (found != view.end()) and
-                                          (found->first.load() == pair.first and
-                                           found->second.load() == pair.second);
-                                 }));
+                                 cuda::proclaim_return_type<bool>(
+                                   [view] __device__(cuco::pair<Key, Value> const& pair) mutable {
+                                     auto const found = view.find(pair.first);
+                                     return (found != view.end()) and
+                                            (found->first.load() == pair.first and
+                                             found->second.load() == pair.second);
+                                   })));
     }
     SECTION("const view")
     {
       // All keys should be found
       REQUIRE(cuco::test::all_of(
-        pairs_begin, pairs_begin + num_keys, [view] __device__(cuco::pair<Key, Value> const& pair) {
+        pairs_begin,
+        pairs_begin + num_keys,
+        cuda::proclaim_return_type<bool>([view] __device__(cuco::pair<Key, Value> const& pair) {
           auto const found = view.find(pair.first);
           return (found != view.end()) and
                  (found->first.load() == pair.first and found->second.load() == pair.second);
-        }));
+        })));
     }
   }
 }
@@ -160,14 +172,17 @@ __inline__ void test_unique_sequence(Map& map, size_type num_keys)
 
   thrust::sequence(thrust::device, d_keys.begin(), d_keys.end());
 
-  auto keys_begin = d_keys.begin();
-  auto pairs_begin =
-    thrust::make_transform_iterator(thrust::make_counting_iterator<size_type>(0),
-                                    [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); });
+  auto keys_begin  = d_keys.begin();
+  auto pairs_begin = thrust::make_transform_iterator(
+    thrust::make_counting_iterator<size_type>(0),
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); }));
   thrust::device_vector<bool> d_contained(num_keys);
 
-  auto zip_equal = [] __device__(auto const& p) { return thrust::get<0>(p) == thrust::get<1>(p); };
-  auto is_even   = [] __device__(auto const& i) { return i % 2 == 0; };
+  auto zip_equal = cuda::proclaim_return_type<bool>(
+    [] __device__(auto const& p) { return thrust::get<0>(p) == thrust::get<1>(p); });
+  auto is_even =
+    cuda::proclaim_return_type<bool>([] __device__(auto const& i) { return i % 2 == 0; });
 
   SECTION("Non-inserted keys should not be contained.")
   {
@@ -196,12 +211,13 @@ __inline__ void test_unique_sequence(Map& map, size_type num_keys)
     REQUIRE(map.size() == num_keys / 2);
 
     map.contains(keys_begin, keys_begin + num_keys, d_contained.begin());
-    REQUIRE(cuco::test::equal(d_contained.begin(),
-                              d_contained.end(),
-                              thrust::counting_iterator<std::size_t>(0),
-                              [] __device__(auto const& idx_contained, auto const& idx) {
-                                return ((idx % 2) == 0) == idx_contained;
-                              }));
+    REQUIRE(cuco::test::equal(
+      d_contained.begin(),
+      d_contained.end(),
+      thrust::counting_iterator<std::size_t>(0),
+      cuda::proclaim_return_type<bool>([] __device__(auto const& idx_contained, auto const& idx) {
+        return ((idx % 2) == 0) == idx_contained;
+      })));
   }
 
   map.insert(pairs_begin, pairs_begin + num_keys);
diff --git a/tests/static_multimap/custom_pair_retrieve_test.cu b/tests/static_multimap/custom_pair_retrieve_test.cu
index 7856b9e20..f6f1b33ae 100644
--- a/tests/static_multimap/custom_pair_retrieve_test.cu
+++ b/tests/static_multimap/custom_pair_retrieve_test.cu
@@ -28,6 +28,8 @@
 #include <thrust/sort.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 #include <cooperative_groups.h>
@@ -93,9 +95,9 @@ void test_non_shmem_pair_retrieve(Map& map, std::size_t const num_pairs)
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_pairs),
                     d_pairs.begin(),
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<cuco::pair<Key, Value>>([] __device__(auto i) {
                       return cuco::pair<Key, Value>{i / 2, i};
-                    });
+                    }));
 
   auto pair_begin = d_pairs.begin();
 
@@ -106,15 +108,17 @@ void test_non_shmem_pair_retrieve(Map& map, std::size_t const num_pairs)
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_pairs),
                     pair_begin,
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<cuco::pair<Key, Value>>([] __device__(auto i) {
                       return cuco::pair<Key, Value>{i, i};
-                    });
+                    }));
 
   // create an array of prefix sum
   thrust::device_vector<int> d_scan(num_pairs);
-  auto count_begin = thrust::make_transform_iterator(
-    thrust::make_counting_iterator<int>(0),
-    [num_pairs] __device__(auto i) { return i < (num_pairs / 2) ? 2 : 1; });
+  auto count_begin =
+    thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
+                                    cuda::proclaim_return_type<int>([num_pairs] __device__(auto i) {
+                                      return i < (num_pairs / 2) ? 2 : 1;
+                                    }));
   thrust::exclusive_scan(thrust::device, count_begin, count_begin + num_pairs, d_scan.begin(), 0);
 
   auto constexpr gold_size  = 300;
@@ -151,21 +155,24 @@ void test_non_shmem_pair_retrieve(Map& map, std::size_t const num_pairs)
   thrust::sort(thrust::device, contained_vals.begin(), contained_vals.end());
 
   // set gold references
-  auto gold_probe         = thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
-                                                    [num_pairs] __device__(auto i) {
-                                                      if (i < num_pairs) { return i / 2; }
-                                                      return i - (int(num_pairs) / 2);
-                                                    });
-  auto gold_contained_key = thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
-                                                            [num_pairs] __device__(auto i) {
-                                                              if (i < num_pairs / 2) { return -1; }
-                                                              return (i - (int(num_pairs) / 2)) / 2;
-                                                            });
-  auto gold_contained_val = thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
-                                                            [num_pairs] __device__(auto i) {
-                                                              if (i < num_pairs / 2) { return -1; }
-                                                              return i - (int(num_pairs) / 2);
-                                                            });
+  auto gold_probe =
+    thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
+                                    cuda::proclaim_return_type<int>([num_pairs] __device__(auto i) {
+                                      if (i < num_pairs) { return i / 2; }
+                                      return i - (int(num_pairs) / 2);
+                                    }));
+  auto gold_contained_key =
+    thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
+                                    cuda::proclaim_return_type<int>([num_pairs] __device__(auto i) {
+                                      if (i < num_pairs / 2) { return -1; }
+                                      return (i - (int(num_pairs) / 2)) / 2;
+                                    }));
+  auto gold_contained_val =
+    thrust::make_transform_iterator(thrust::make_counting_iterator<int>(0),
+                                    cuda::proclaim_return_type<int>([num_pairs] __device__(auto i) {
+                                      if (i < num_pairs / 2) { return -1; }
+                                      return i - (int(num_pairs) / 2);
+                                    }));
 
   auto key_equal   = thrust::equal_to<Key>{};
   auto value_equal = thrust::equal_to<Value>{};
diff --git a/tests/static_multimap/custom_type_test.cu b/tests/static_multimap/custom_type_test.cu
index f53719205..58d653f76 100644
--- a/tests/static_multimap/custom_type_test.cu
+++ b/tests/static_multimap/custom_type_test.cu
@@ -27,6 +27,8 @@
 #include <thrust/transform.h>
 #include <thrust/tuple.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 #include <tuple>
@@ -72,17 +74,17 @@ __inline__ void test_custom_key_value_type(Map& map, std::size_t num_pairs)
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_pairs),
                     insert_keys.begin(),
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<Key>([] __device__(auto i) {
                       return Key{i, i};
-                    });
+                    }));
 
   thrust::transform(thrust::device,
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_pairs),
                     insert_values.begin(),
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<Value>([] __device__(auto i) {
                       return Value{i, i};
-                    });
+                    }));
 
   auto pair_begin =
     thrust::make_zip_iterator(thrust::make_tuple(insert_keys.begin(), insert_values.begin()));
@@ -106,21 +108,22 @@ __inline__ void test_custom_key_value_type(Map& map, std::size_t num_pairs)
     REQUIRE(size == num_pairs);
 
     // sort before compare
-    thrust::sort(
-      thrust::device,
-      found_pairs.begin(),
-      found_pairs.end(),
-      [] __device__(const cuco::pair<Key, Value>& lhs, const cuco::pair<Key, Value>& rhs) {
-        return lhs.first.a < rhs.first.a;
-      });
+    thrust::sort(thrust::device,
+                 found_pairs.begin(),
+                 found_pairs.end(),
+                 cuda::proclaim_return_type<bool>([] __device__(const cuco::pair<Key, Value>& lhs,
+                                                                const cuco::pair<Key, Value>& rhs) {
+                   return lhs.first.a < rhs.first.a;
+                 }));
 
     REQUIRE(
       cuco::test::equal(pair_begin,
                         pair_begin + num_pairs,
                         found_pairs.begin(),
-                        [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
-                          return lhs.first.a == rhs.first.a;
-                        }));
+                        cuda::proclaim_return_type<bool>(
+                          [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
+                            return lhs.first.a == rhs.first.a;
+                          })));
   }
 
   SECTION("Non-matches are not included in the output")
@@ -135,9 +138,9 @@ __inline__ void test_custom_key_value_type(Map& map, std::size_t num_pairs)
                       thrust::counting_iterator<int>(0),
                       thrust::counting_iterator<int>(num),
                       query_key_begin,
-                      [] __device__(auto i) {
+                      cuda::proclaim_return_type<Key>([] __device__(auto i) {
                         return Key{i, i};
-                      });
+                      }));
 
     auto count = map.count(query_key_begin, query_key_begin + num, stream, key_pair_equals{});
     REQUIRE(count == num_pairs);
@@ -150,20 +153,21 @@ __inline__ void test_custom_key_value_type(Map& map, std::size_t num_pairs)
     REQUIRE(size == num_pairs);
 
     // sort before compare
-    thrust::sort(
-      thrust::device,
-      found_pairs.begin(),
-      found_pairs.end(),
-      [] __device__(const cuco::pair<Key, Value>& lhs, const cuco::pair<Key, Value>& rhs) {
-        return lhs.first.a < rhs.first.a;
-      });
+    thrust::sort(thrust::device,
+                 found_pairs.begin(),
+                 found_pairs.end(),
+                 cuda::proclaim_return_type<bool>([] __device__(const cuco::pair<Key, Value>& lhs,
+                                                                const cuco::pair<Key, Value>& rhs) {
+                   return lhs.first.a < rhs.first.a;
+                 }));
     REQUIRE(
       cuco::test::equal(pair_begin,
                         pair_begin + num_pairs,
                         found_pairs.begin(),
-                        [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
-                          return lhs.first.a == rhs.first.a;
-                        }));
+                        cuda::proclaim_return_type<bool>(
+                          [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
+                            return lhs.first.a == rhs.first.a;
+                          })));
   }
 
   SECTION("Outer functions include non-matches in the output")
@@ -177,9 +181,9 @@ __inline__ void test_custom_key_value_type(Map& map, std::size_t num_pairs)
                       thrust::counting_iterator<int>(0),
                       thrust::counting_iterator<int>(num),
                       query_key_begin,
-                      [] __device__(auto i) {
+                      cuda::proclaim_return_type<Key>([] __device__(auto i) {
                         return Key{i, i};
-                      });
+                      }));
 
     auto count_outer =
       map.count_outer(query_key_begin, query_key_begin + num, stream, key_pair_equals{});
diff --git a/tests/static_multimap/heterogeneous_lookup_test.cu b/tests/static_multimap/heterogeneous_lookup_test.cu
index 5a5b8b242..6f8b2c2b8 100644
--- a/tests/static_multimap/heterogeneous_lookup_test.cu
+++ b/tests/static_multimap/heterogeneous_lookup_test.cu
@@ -25,6 +25,8 @@
 #include <thrust/iterator/transform_iterator.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 #include <tuple>
@@ -103,11 +105,13 @@ TEMPLATE_TEST_CASE("Heterogeneous lookup",
                         cuco::linear_probing<1, custom_hasher>>
     map{capacity, cuco::empty_key<Key>{sentinel_key}, cuco::empty_value<Value>{sentinel_value}};
 
-  auto insert_pairs =
-    thrust::make_transform_iterator(thrust::counting_iterator<int>(0),
-                                    [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); });
-  auto probe_keys = thrust::make_transform_iterator(thrust::counting_iterator<int>(0),
-                                                    [] __device__(auto i) { return ProbeKey(i); });
+  auto insert_pairs = thrust::make_transform_iterator(
+    thrust::counting_iterator<int>(0),
+    cuda::proclaim_return_type<cuco::pair<Key, Value>>(
+      [] __device__(auto i) { return cuco::pair<Key, Value>(i, i); }));
+  auto probe_keys = thrust::make_transform_iterator(
+    thrust::counting_iterator<int>(0),
+    cuda::proclaim_return_type<ProbeKey>([] __device__(auto i) { return ProbeKey(i); }));
 
   SECTION("All inserted keys-value pairs should be contained")
   {
diff --git a/tests/static_multimap/insert_if_test.cu b/tests/static_multimap/insert_if_test.cu
index 5d5648e71..53e150730 100644
--- a/tests/static_multimap/insert_if_test.cu
+++ b/tests/static_multimap/insert_if_test.cu
@@ -24,13 +24,15 @@
 #include <thrust/sequence.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 template <typename Key, typename Map, typename PairIt, typename KeyIt>
 __inline__ void test_insert_if(Map& map, PairIt pair_begin, KeyIt key_begin, std::size_t size)
 {
   // 50% insertion
-  auto pred_lambda = [] __device__(Key k) { return k % 2 == 0; };
+  auto pred_lambda = cuda::proclaim_return_type<bool>([] __device__(Key k) { return k % 2 == 0; });
 
   map.insert_if(pair_begin, pair_begin + size, key_begin, pred_lambda);
 
@@ -63,9 +65,9 @@ TEMPLATE_TEST_CASE_SIG(
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_keys),
                     d_pairs.begin(),
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<cuco::pair<Key, Value>>([] __device__(auto i) {
                       return cuco::pair<Key, Value>{i, i};
-                    });
+                    }));
 
   using probe = std::conditional_t<Probe == cuco::test::probe_sequence::linear_probing,
                                    cuco::linear_probing<1, cuco::default_hash_function<Key>>,
diff --git a/tests/static_multimap/multiplicity_test.cu b/tests/static_multimap/multiplicity_test.cu
index 5de83a042..b1c4cd1ce 100644
--- a/tests/static_multimap/multiplicity_test.cu
+++ b/tests/static_multimap/multiplicity_test.cu
@@ -27,6 +27,8 @@
 #include <thrust/sort.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 template <typename Map>
@@ -44,9 +46,9 @@ __inline__ void test_multiplicity_two(Map& map, std::size_t num_items)
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_items),
                     d_pairs.begin(),
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<cuco::pair<Key, Value>>([] __device__(auto i) {
                       return cuco::pair<Key, Value>{i / 2, i};
-                    });
+                    }));
 
   thrust::device_vector<cuco::pair<Key, Value>> d_results(num_items);
 
@@ -91,22 +93,23 @@ __inline__ void test_multiplicity_two(Map& map, std::size_t num_items)
     REQUIRE(size == num_items);
 
     // sort before compare
-    thrust::sort(
-      thrust::device,
-      d_results.begin(),
-      d_results.end(),
-      [] __device__(const cuco::pair<Key, Value>& lhs, const cuco::pair<Key, Value>& rhs) {
-        if (lhs.first != rhs.first) { return lhs.first < rhs.first; }
-        return lhs.second < rhs.second;
-      });
+    thrust::sort(thrust::device,
+                 d_results.begin(),
+                 d_results.end(),
+                 cuda::proclaim_return_type<bool>([] __device__(const cuco::pair<Key, Value>& lhs,
+                                                                const cuco::pair<Key, Value>& rhs) {
+                   if (lhs.first != rhs.first) { return lhs.first < rhs.first; }
+                   return lhs.second < rhs.second;
+                 }));
 
     REQUIRE(
       cuco::test::equal(pair_begin,
                         pair_begin + num_items,
                         output_begin,
-                        [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
-                          return lhs.first == rhs.first and lhs.second == rhs.second;
-                        }));
+                        cuda::proclaim_return_type<bool>(
+                          [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
+                            return lhs.first == rhs.first and lhs.second == rhs.second;
+                          })));
   }
 
   SECTION("count and count_outer should return the same value.")
@@ -129,22 +132,23 @@ __inline__ void test_multiplicity_two(Map& map, std::size_t num_items)
     REQUIRE(size == size_outer);
 
     // sort before compare
-    thrust::sort(
-      thrust::device,
-      d_results.begin(),
-      d_results.end(),
-      [] __device__(const cuco::pair<Key, Value>& lhs, const cuco::pair<Key, Value>& rhs) {
-        if (lhs.first != rhs.first) { return lhs.first < rhs.first; }
-        return lhs.second < rhs.second;
-      });
+    thrust::sort(thrust::device,
+                 d_results.begin(),
+                 d_results.end(),
+                 cuda::proclaim_return_type<bool>([] __device__(const cuco::pair<Key, Value>& lhs,
+                                                                const cuco::pair<Key, Value>& rhs) {
+                   if (lhs.first != rhs.first) { return lhs.first < rhs.first; }
+                   return lhs.second < rhs.second;
+                 }));
 
     REQUIRE(
       cuco::test::equal(pair_begin,
                         pair_begin + num_items,
                         output_begin,
-                        [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
-                          return lhs.first == rhs.first and lhs.second == rhs.second;
-                        }));
+                        cuda::proclaim_return_type<bool>(
+                          [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
+                            return lhs.first == rhs.first and lhs.second == rhs.second;
+                          })));
   }
 }
 
diff --git a/tests/static_multimap/non_match_test.cu b/tests/static_multimap/non_match_test.cu
index 94023af56..1be809b63 100644
--- a/tests/static_multimap/non_match_test.cu
+++ b/tests/static_multimap/non_match_test.cu
@@ -26,6 +26,8 @@
 #include <thrust/sort.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 template <typename Key, typename Value, typename Map, typename PairIt, typename KeyIt>
@@ -50,22 +52,23 @@ __inline__ void test_non_matches(Map& map, PairIt pair_begin, KeyIt key_begin, s
     REQUIRE(size == num_keys);
 
     // sort before compare
-    thrust::sort(
-      thrust::device,
-      output_begin,
-      output_end,
-      [] __device__(const cuco::pair<Key, Value>& lhs, const cuco::pair<Key, Value>& rhs) {
-        if (lhs.first != rhs.first) { return lhs.first < rhs.first; }
-        return lhs.second < rhs.second;
-      });
+    thrust::sort(thrust::device,
+                 output_begin,
+                 output_end,
+                 cuda::proclaim_return_type<bool>([] __device__(const cuco::pair<Key, Value>& lhs,
+                                                                const cuco::pair<Key, Value>& rhs) {
+                   if (lhs.first != rhs.first) { return lhs.first < rhs.first; }
+                   return lhs.second < rhs.second;
+                 }));
 
     REQUIRE(
       cuco::test::equal(pair_begin,
                         pair_begin + num_keys,
                         output_begin,
-                        [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
-                          return lhs.first == rhs.first and lhs.second == rhs.second;
-                        }));
+                        cuda::proclaim_return_type<bool>(
+                          [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
+                            return lhs.first == rhs.first and lhs.second == rhs.second;
+                          })));
   }
 
   SECTION("Output of count_outer and retrieve_outer should be coherent.")
@@ -82,34 +85,36 @@ __inline__ void test_non_matches(Map& map, PairIt pair_begin, KeyIt key_begin, s
     REQUIRE(size == (num_keys + num_keys / 2));
 
     // sort before compare
-    thrust::sort(
-      thrust::device,
-      output_begin,
-      output_end,
-      [] __device__(const cuco::pair<Key, Value>& lhs, const cuco::pair<Key, Value>& rhs) {
-        if (lhs.first != rhs.first) { return lhs.first < rhs.first; }
-        return lhs.second < rhs.second;
-      });
+    thrust::sort(thrust::device,
+                 output_begin,
+                 output_end,
+                 cuda::proclaim_return_type<bool>([] __device__(const cuco::pair<Key, Value>& lhs,
+                                                                const cuco::pair<Key, Value>& rhs) {
+                   if (lhs.first != rhs.first) { return lhs.first < rhs.first; }
+                   return lhs.second < rhs.second;
+                 }));
 
     // create gold reference
     thrust::device_vector<cuco::pair<Key, Value>> gold(size);
     auto gold_begin = gold.begin();
-    thrust::transform(thrust::device,
-                      thrust::counting_iterator<int>(0),
-                      thrust::counting_iterator<int>(size),
-                      gold_begin,
-                      [num_keys] __device__(auto i) {
-                        if (i < num_keys) { return cuco::pair<Key, Value>{i / 2, i}; }
-                        return cuco::pair<Key, Value>{i - num_keys / 2, -1};
-                      });
+    thrust::transform(
+      thrust::device,
+      thrust::counting_iterator<int>(0),
+      thrust::counting_iterator<int>(size),
+      gold_begin,
+      cuda::proclaim_return_type<cuco::pair<Key, Value>>([num_keys] __device__(auto i) {
+        if (i < num_keys) { return cuco::pair<Key, Value>{i / 2, i}; }
+        return cuco::pair<Key, Value>{i - num_keys / 2, -1};
+      }));
 
     REQUIRE(
       cuco::test::equal(gold_begin,
                         gold_begin + size,
                         output_begin,
-                        [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
-                          return lhs.first == rhs.first and lhs.second == rhs.second;
-                        }));
+                        cuda::proclaim_return_type<bool>(
+                          [] __device__(cuco::pair<Key, Value> lhs, cuco::pair<Key, Value> rhs) {
+                            return lhs.first == rhs.first and lhs.second == rhs.second;
+                          })));
   }
 }
 
@@ -135,9 +140,9 @@ TEMPLATE_TEST_CASE_SIG(
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_keys),
                     d_pairs.begin(),
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<cuco::pair<Key, Value>>([] __device__(auto i) {
                       return cuco::pair<Key, Value>{i / 2, i};
-                    });
+                    }));
 
   using probe = std::conditional_t<Probe == cuco::test::probe_sequence::linear_probing,
                                    cuco::linear_probing<1, cuco::default_hash_function<Key>>,
diff --git a/tests/static_multimap/pair_function_test.cu b/tests/static_multimap/pair_function_test.cu
index 3ef49377d..8da11521a 100644
--- a/tests/static_multimap/pair_function_test.cu
+++ b/tests/static_multimap/pair_function_test.cu
@@ -27,6 +27,8 @@
 #include <thrust/transform.h>
 #include <thrust/tuple.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 // Custom pair equal
@@ -53,9 +55,9 @@ __inline__ void test_pair_functions(Map& map, PairIt pair_begin, std::size_t num
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_pairs),
                     pair_begin,
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<cuco::pair<Key, Value>>([] __device__(auto i) {
                       return cuco::pair<Key, Value>{i, i};
-                    });
+                    }));
 
   SECTION("pair_contains returns true for all inserted pairs and false for non-inserted ones.")
   {
@@ -128,9 +130,9 @@ TEMPLATE_TEST_CASE_SIG(
                     thrust::counting_iterator<int>(0),
                     thrust::counting_iterator<int>(num_pairs),
                     d_pairs.begin(),
-                    [] __device__(auto i) {
+                    cuda::proclaim_return_type<cuco::pair<Key, Value>>([] __device__(auto i) {
                       return cuco::pair<Key, Value>{i / 2, i};
-                    });
+                    }));
 
   using probe = std::conditional_t<Probe == cuco::test::probe_sequence::linear_probing,
                                    cuco::linear_probing<1, cuco::default_hash_function<Key>>,
diff --git a/tests/static_set/heterogeneous_lookup_test.cu b/tests/static_set/heterogeneous_lookup_test.cu
index cbc0efac3..3bd631a40 100644
--- a/tests/static_set/heterogeneous_lookup_test.cu
+++ b/tests/static_set/heterogeneous_lookup_test.cu
@@ -25,6 +25,8 @@
 #include <thrust/iterator/transform_iterator.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 #include <tuple>
@@ -98,10 +100,12 @@ TEMPLATE_TEST_CASE_SIG(
                                                probe_type>{
     capacity, cuco::empty_key<Key>{sentinel_key}, custom_key_equal{}, probe};
 
-  auto insert_pairs = thrust::make_transform_iterator(thrust::counting_iterator<int>(0),
-                                                      [] __device__(auto i) { return Key{i}; });
-  auto probe_keys   = thrust::make_transform_iterator(thrust::counting_iterator<int>(0),
-                                                    [] __device__(auto i) { return ProbeKey(i); });
+  auto insert_pairs = thrust::make_transform_iterator(
+    thrust::counting_iterator<int>(0),
+    cuda::proclaim_return_type<Key>([] __device__(auto i) { return Key{i}; }));
+  auto probe_keys = thrust::make_transform_iterator(
+    thrust::counting_iterator<int>(0),
+    cuda::proclaim_return_type<ProbeKey>([] __device__(auto i) { return ProbeKey(i); }));
 
   SECTION("All inserted keys should be contained")
   {
diff --git a/tests/static_set/insert_and_find_test.cu b/tests/static_set/insert_and_find_test.cu
index 278510e08..55f293898 100644
--- a/tests/static_set/insert_and_find_test.cu
+++ b/tests/static_set/insert_and_find_test.cu
@@ -22,6 +22,8 @@
 #include <thrust/iterator/counting_iterator.h>
 #include <thrust/iterator/transform_iterator.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 template <typename Set>
@@ -34,8 +36,9 @@ __inline__ void test_insert_and_find(Set& set, std::size_t num_keys)
     if constexpr (cg_size == 1) {
       return thrust::counting_iterator<Key>(0);
     } else {
-      return thrust::make_transform_iterator(thrust::counting_iterator<Key>(0),
-                                             [] __device__(auto i) { return i / cg_size; });
+      return thrust::make_transform_iterator(
+        thrust::counting_iterator<Key>(0),
+        cuda::proclaim_return_type<Key>([] __device__(auto i) { return i / cg_size; }));
     }
   }();
   auto const keys_end = [&]() {
diff --git a/tests/static_set/unique_sequence_test.cu b/tests/static_set/unique_sequence_test.cu
index 53ede7524..663560807 100644
--- a/tests/static_set/unique_sequence_test.cu
+++ b/tests/static_set/unique_sequence_test.cu
@@ -27,6 +27,8 @@
 #include <thrust/sort.h>
 #include <thrust/transform.h>
 
+#include <cuda/functional>
+
 #include <catch2/catch_template_test_macros.hpp>
 
 using size_type = int32_t;
@@ -43,8 +45,10 @@ __inline__ void test_unique_sequence(Set& set, size_type num_keys)
   auto keys_begin = d_keys.begin();
   thrust::device_vector<bool> d_contained(num_keys);
 
-  auto zip_equal = [] __device__(auto const& p) { return thrust::get<0>(p) == thrust::get<1>(p); };
-  auto is_even   = [] __device__(auto const& i) { return i % 2 == 0; };
+  auto zip_equal = cuda::proclaim_return_type<bool>(
+    [] __device__(auto const& p) { return thrust::get<0>(p) == thrust::get<1>(p); });
+  auto is_even =
+    cuda::proclaim_return_type<bool>([] __device__(auto const& i) { return i % 2 == 0; });
 
   SECTION("Non-inserted keys should not be contained.")
   {
@@ -73,12 +77,13 @@ __inline__ void test_unique_sequence(Set& set, size_type num_keys)
     REQUIRE(set.size() == num_keys / 2);
 
     set.contains(keys_begin, keys_begin + num_keys, d_contained.begin());
-    REQUIRE(cuco::test::equal(d_contained.begin(),
-                              d_contained.end(),
-                              thrust::counting_iterator<std::size_t>(0),
-                              [] __device__(auto const& idx_contained, auto const& idx) {
-                                return ((idx % 2) == 0) == idx_contained;
-                              }));
+    REQUIRE(cuco::test::equal(
+      d_contained.begin(),
+      d_contained.end(),
+      thrust::counting_iterator<std::size_t>(0),
+      cuda::proclaim_return_type<bool>([] __device__(auto const& idx_contained, auto const& idx) {
+        return ((idx % 2) == 0) == idx_contained;
+      })));
   }
 
   set.insert(keys_begin, keys_begin + num_keys);