modernize-use-equals-default

.clang-tidy

@@ -26,7 +26,6 @@ Checks:
   - 'modernize-*'
   - '-modernize-use-integer-sign-comparison'
   - '-modernize-use-nodiscard'
-  - '-modernize-use-equals-default'
   - '-modernize-return-braced-init-list'
   - '-modernize-use-auto'
   # END REMOVE ME

c/parallel/test/test_radix_sort.cpp

@@ -37,7 +37,7 @@ struct TestParameters
   static constexpr bool m_descending     = descending;
   static constexpr bool m_overwrite_okay = overwrite_okay;
 
-  constexpr TestParameters() {}
+  constexpr TestParameters() = default;
 
   bool is_descending() const
   {

c/parallel/test/test_segmented_sort.cpp

@@ -49,7 +49,7 @@ struct TestParameters
   static constexpr bool m_descending     = descending;
   static constexpr bool m_overwrite_okay = overwrite_okay;
 
-  constexpr TestParameters() {}
+  constexpr TestParameters() = default;
 
   constexpr bool is_descending() const
   {

c2h/include/c2h/checked_allocator.cuh

@@ -160,7 +160,7 @@ public:
     using other = checked_cuda_allocator<U>;
   };
 
-  _CCCL_HOST_DEVICE checked_cuda_allocator() {}
+  checked_cuda_allocator() = default;
 
   _CCCL_HOST_DEVICE checked_cuda_allocator(const checked_cuda_allocator& other)
       : base(other)
@@ -173,7 +173,7 @@ public:
 
   checked_cuda_allocator& operator=(const checked_cuda_allocator&) = default;
 
-  _CCCL_HOST_DEVICE ~checked_cuda_allocator() {}
+  ~checked_cuda_allocator() = default;
 };
 
 struct checked_host_memory_resource final : public THRUST_NS_QUALIFIER::mr::new_delete_resource_base

cub/cub/block/block_load_to_shared.cuh

@@ -228,7 +228,8 @@ private:
   class token_impl
   {
     friend struct BlockLoadToShared;
-    _CCCL_DEVICE_API _CCCL_FORCEINLINE token_impl() {} // ctor must have a body to avoid token_impl{} to compile
+    _CCCL_DEVICE_API _CCCL_FORCEINLINE token_impl() {} // NOLINT(modernize-use-equals-default) ctor must have a body to
+                                                       // avoid token_impl{} to compile
 
     // NOLINTBEGIN(modernize-use-equals-delete)
     token_impl(const token_impl&)            = delete;

cub/cub/thread/thread_operators.cuh

@@ -167,7 +167,7 @@ struct ScanBySegmentOp
   ScanOpT op;
 
   /// Constructor
-  _CCCL_HOST_DEVICE _CCCL_FORCEINLINE ScanBySegmentOp() {}
+  _CCCL_FORCEINLINE ScanBySegmentOp() = default;
 
   /// Constructor
   _CCCL_HOST_DEVICE _CCCL_FORCEINLINE ScanBySegmentOp(ScanOpT op)
@@ -301,7 +301,7 @@ struct ReduceBySegmentOp
   ReductionOpT op;
 
   /// Constructor
-  _CCCL_HOST_DEVICE _CCCL_FORCEINLINE ReduceBySegmentOp() {}
+  _CCCL_FORCEINLINE ReduceBySegmentOp() = default;
 
   /// Constructor
   _CCCL_HOST_DEVICE _CCCL_FORCEINLINE ReduceBySegmentOp(ReductionOpT op)
@@ -362,7 +362,7 @@ struct ReduceByKeyOp
   ReductionOpT op;
 
   /// Constructor
-  _CCCL_HOST_DEVICE _CCCL_FORCEINLINE ReduceByKeyOp() {}
+  _CCCL_FORCEINLINE ReduceByKeyOp() = default;
 
   /// Constructor
   _CCCL_HOST_DEVICE _CCCL_FORCEINLINE ReduceByKeyOp(ReductionOpT op)

cub/cub/util_type.cuh

@@ -705,7 +705,7 @@ struct KeyValuePair
   Value value; ///< Item value
 
   /// Constructor
-  _CCCL_HOST_DEVICE _CCCL_FORCEINLINE KeyValuePair() {}
+  _CCCL_FORCEINLINE KeyValuePair() = default;
 
   /// Constructor
   _CCCL_HOST_DEVICE _CCCL_FORCEINLINE KeyValuePair(Key const& key, Value const& value)

cub/test/catch2_test_device_scan_iterators.cu

@@ -179,7 +179,7 @@ class custom_accumulator_t
   {}
 
 public:
-  __host__ __device__ custom_accumulator_t() {}
+  custom_accumulator_t() = default;
 
   __host__ __device__ custom_accumulator_t(const custom_accumulator_t& in)
       : m_val(in.is_valid() * in.get())

cub/test/catch2_test_device_transform.cu

@@ -521,10 +521,12 @@ struct non_trivial
       : data(data)
   {}
 
+  // NOLINTNEXTLINE(modernize-use-equals-default)
   __host__ __device__ non_trivial(const non_trivial& nt)
       : data(nt.data)
   {}
 
+  // NOLINTNEXTLINE(modernize-use-equals-default)
   __host__ __device__ auto operator=(const non_trivial& nt) -> non_trivial&
   {
     data = nt.data;

cudax/test/execution/common/utility.cuh

@@ -67,13 +67,16 @@ struct potentially_throwing
 
   _CCCL_HOST_DEVICE potentially_throwing(potentially_throwing&&) noexcept(false) {}
 
-  _CCCL_HOST_DEVICE potentially_throwing(const potentially_throwing&) noexcept(false) {}
+  _CCCL_HOST_DEVICE
+  potentially_throwing(const potentially_throwing&) noexcept(false) // NOLINT(modernize-use-equals-default)
+  {}
 
   _CCCL_HOST_DEVICE potentially_throwing& operator=(potentially_throwing&&) noexcept(false)
   {
     return *this;
   }
 
+  // NOLINTNEXTLINE(modernize-use-equals-default)
   _CCCL_HOST_DEVICE potentially_throwing& operator=(const potentially_throwing&) noexcept(false)
   {
     return *this;

libcudacxx/include/cuda/__stream/launch_transform.h

@@ -115,7 +115,9 @@ struct _CCCL_TYPE_VISIBILITY_DEFAULT __launch_transform_t
   struct __optional_with_a_destructor : ::cuda::std::optional<_Tp>
   {
     using ::cuda::std::optional<_Tp>::optional;
-    ~__optional_with_a_destructor() {}
+    // Use of explicit destructor is intentional. Without it, the argument may have a trivial
+    // destructor and hence would be performed by the callee.
+    ~__optional_with_a_destructor() {} // NOLINT(modernize-use-equals-default)
 
     template <class _Fn>
     _CCCL_API inline _CCCL_CONSTEXPR_CXX20 _Tp& __emplace_from_fn(_Fn&& __fn)

libcudacxx/include/cuda/std/__optional/optional.h

@@ -120,7 +120,9 @@ class optional : private __optional_move_assign_base<_Tp>
   static_assert(!is_array_v<value_type>, "instantiation of optional with an array type is ill-formed");
 
 public:
-  _CCCL_API constexpr optional() noexcept {}
+  // Use of {} vs = default is deliberate. = default may value-initialize, while {} is
+  // guaranteed to do absolutely nothing.
+  _CCCL_API constexpr optional() noexcept {} // NOLINT(modernize-use-equals-default)
   _CCCL_HIDE_FROM_ABI constexpr optional(const optional&) = default;
   _CCCL_HIDE_FROM_ABI constexpr optional(optional&&)      = default;
   _CCCL_API constexpr optional(nullopt_t) noexcept {}

libcudacxx/include/cuda/std/__optional/optional_ref.h

@@ -89,7 +89,9 @@ class optional<_Tp&>
 public:
   using value_type = __raw_type&;
 
-  _CCCL_API constexpr optional() noexcept {}
+  // Use of {} vs = default is deliberate. = default may value-initialize, while {} is
+  // guaranteed to do absolutely nothing.
+  _CCCL_API constexpr optional() noexcept {} // NOLINT(modernize-use-equals-default)
   _CCCL_HIDE_FROM_ABI constexpr optional(const optional&) noexcept = default;
   _CCCL_HIDE_FROM_ABI constexpr optional(optional&&) noexcept      = default;
   _CCCL_API constexpr optional(nullopt_t) noexcept {}

libcudacxx/include/cuda/std/__tuple_dir/tuple_leaf.h

@@ -105,8 +105,11 @@ class __tuple_leaf<_Ip, _Hp, __tuple_leaf_specialization::__default>
 #endif // !_CCCL_BUILTIN_REFERENCE_CONSTRUCTS_FROM_TEMPORARY
 
 public:
+  // The compiler-generated constructor would not value-initialize trivial types, but the
+  // standard requires that we do.
   _CCCL_EXEC_CHECK_DISABLE
-  _CCCL_API constexpr __tuple_leaf() noexcept(is_nothrow_default_constructible_v<_Hp>)
+  _CCCL_API constexpr __tuple_leaf() // NOLINT(modernize-use-equals-default)
+    noexcept(is_nothrow_default_constructible_v<_Hp>)
       : __value_()
   {}
 
@@ -227,14 +230,19 @@ class __tuple_leaf<_Ip, _Hp, __tuple_leaf_specialization::__synthesize_assignmen
   _CCCL_EXEC_CHECK_DISABLE
   __tuple_leaf(__tuple_leaf&& __t) = default;
 
+  // Do not use = default here. The value type may be a reference, in which case the defaulted
+  // assignment constructor is implicitly deleted (a quirk in the C++ spec meant).
   _CCCL_EXEC_CHECK_DISABLE
-  _CCCL_API constexpr __tuple_leaf& operator=(const __tuple_leaf& __t) noexcept
+  _CCCL_API constexpr __tuple_leaf& operator=(const __tuple_leaf& __t) noexcept // NOLINT(modernize-use-equals-default)
   {
     __value_ = __t.__value_;
     return *this;
   }
+
+  // Do not use = default here. The value type may be a reference, in which case the defaulted
+  // assignment constructor is implicitly deleted (a quirk in the C++ spec meant).
   _CCCL_EXEC_CHECK_DISABLE
-  _CCCL_API constexpr __tuple_leaf& operator=(__tuple_leaf&& __t) noexcept
+  _CCCL_API constexpr __tuple_leaf& operator=(__tuple_leaf&& __t) noexcept // NOLINT(modernize-use-equals-default)
   {
     __value_ = ::cuda::std::move(__t.__value_);
     return *this;
@@ -267,8 +275,11 @@ template <size_t _Ip, class _Hp>
 class __tuple_leaf<_Ip, _Hp, __tuple_leaf_specialization::__empty_non_final> : private remove_const_t<_Hp>
 {
 public:
+  // The compiler-generated constructor would not value-initialize trivial types, but the
+  // standard requires that we do.
   _CCCL_EXEC_CHECK_DISABLE
-  _CCCL_API constexpr __tuple_leaf() noexcept(is_nothrow_default_constructible_v<_Hp>)
+  _CCCL_API constexpr __tuple_leaf() // NOLINT(modernize-use-equals-default)
+    noexcept(is_nothrow_default_constructible_v<_Hp>)
       : _Hp()
   {}
 

libcudacxx/include/cuda/std/__utility/typeid.h

@@ -302,9 +302,7 @@ struct __type_info_ref_ : __type_info
       : __type_info(__other)
   {}
 
-  _CCCL_API constexpr __type_info_ref_(__type_info_ref_ const& __other) noexcept
-      : __type_info(__other)
-  {}
+  _CCCL_HIDE_FROM_ABI constexpr __type_info_ref_(__type_info_ref_ const& __other) noexcept = default;
 };
 
 [[nodiscard]] _CCCL_API constexpr __type_info_ref_ __type_info_ptr_::operator*() const noexcept

libcudacxx/test/support/test_iterators.h

@@ -983,13 +983,7 @@ struct NonThrowingIterator
       , current_(rhs.current_)
   {}
 
-  TEST_FUNC NonThrowingIterator& operator=(const NonThrowingIterator& rhs) noexcept
-  {
-    begin_   = rhs.begin_;
-    end_     = rhs.end_;
-    current_ = rhs.current_;
-    return *this;
-  }
+  NonThrowingIterator& operator=(const NonThrowingIterator& rhs) noexcept = default;
 
   TEST_FUNC reference operator*() const noexcept
   {
@@ -2066,7 +2060,7 @@ class advance_only_iterator
   using pointer           = int*;
   using reference         = int&;
 
-  TEST_FUNC constexpr advance_only_iterator() {}
+  constexpr advance_only_iterator() = default;
   TEST_FUNC constexpr advance_only_iterator(int* iter)
       : iter_(iter)
   {}

thrust/benchmarks/bench/copy/basic.cu

@@ -41,11 +41,13 @@ struct non_trivial
   {}
 
   // the user-defined copy constructor prevents the type from being trivially copyable
+  // NOLINTNEXTLINE(modernize-use-equals-default)
   _CCCL_HOST_DEVICE non_trivial(const non_trivial& nt)
       : a(nt.a)
       , b(nt.b)
   {}
 
+  // NOLINTNEXTLINE(modernize-use-equals-default)
   _CCCL_HOST_DEVICE non_trivial& operator=(const non_trivial& nt)
   {
     a = nt.a;

thrust/benchmarks/bench/uninitialized_copy/basic.cu

@@ -37,6 +37,7 @@ struct no_copy
   {}
 
   // the user-defined copy constructor prevents the type from being trivially copyable
+  // NOLINTNEXTLINE(modernize-use-equals-default)
   _CCCL_HOST_DEVICE no_copy(const no_copy& nt)
       : a(nt.a)
   {}

thrust/examples/bounding_box.cu

@@ -29,7 +29,7 @@ struct point2d
 struct bbox
 {
   // construct an empty box
-  __host__ __device__ bbox() {}
+  bbox() = default;
 
   // construct a box from a single point
   __host__ __device__ bbox(const point2d& point)

thrust/examples/cuda/range_view.cu

@@ -34,7 +34,7 @@ public:
       : first(first)
       , last(last)
   {}
-  __host__ __device__ ~range_view() {}
+  ~range_view() = default;
 
   __host__ __device__ difference_type size() const
   {

thrust/examples/include/timer.h

@@ -77,7 +77,7 @@ struct timer
     restart();
   }
 
-  ~timer() {}
+  ~timer() = default;
 
   void restart()
   {

thrust/examples/uninitialized_vector.cu

@@ -21,11 +21,11 @@ struct uninitialized_allocator : thrust::device_allocator<T>
   // marked __host__ __device__, but the current Thrust device_allocator
   // can only be constructed and destroyed on the host; therefore, we
   // define these as host only
-  __host__ uninitialized_allocator() {}
+  __host__ uninitialized_allocator() {} // NOLINT(modernize-use-equals-default)
   __host__ uninitialized_allocator(const uninitialized_allocator& other)
       : thrust::device_allocator<T>(other)
   {}
-  __host__ ~uninitialized_allocator() {}
+  __host__ ~uninitialized_allocator() {} // NOLINT(modernize-use-equals-default)
 
   uninitialized_allocator& operator=(const uninitialized_allocator&) = default;
 

thrust/testing/allocator.cu

@@ -22,7 +22,7 @@
 template <typename T>
 struct my_allocator_with_custom_construct1 : thrust::device_malloc_allocator<T>
 {
-  _CCCL_HOST_DEVICE my_allocator_with_custom_construct1() {}
+  my_allocator_with_custom_construct1() = default;
 
   _CCCL_HOST_DEVICE void construct(T* p)
   {
@@ -43,7 +43,7 @@ DECLARE_VARIABLE_UNITTEST(TestAllocatorCustomDefaultConstruct);
 template <typename T>
 struct my_allocator_with_custom_construct2 : thrust::device_malloc_allocator<T>
 {
-  _CCCL_HOST_DEVICE my_allocator_with_custom_construct2() {}
+  my_allocator_with_custom_construct2() = default;
 
   template <typename Arg>
   _CCCL_HOST_DEVICE void construct(T* p, const Arg&)
@@ -80,13 +80,13 @@ struct my_allocator_with_custom_destroy
 
   static bool g_state;
 
-  _CCCL_HOST my_allocator_with_custom_destroy() {}
+  _CCCL_HOST my_allocator_with_custom_destroy() {} // NOLINT(modernize-use-equals-default)
 
   _CCCL_HOST my_allocator_with_custom_destroy(const my_allocator_with_custom_destroy& other)
       : use_me_to_alloc(other.use_me_to_alloc)
   {}
 
-  _CCCL_HOST ~my_allocator_with_custom_destroy() {}
+  _CCCL_HOST ~my_allocator_with_custom_destroy() {} // NOLINT(modernize-use-equals-default)
 
   _CCCL_HOST_DEVICE void destroy(T*) noexcept
   {
@@ -149,13 +149,13 @@ struct my_minimal_allocator
   using reference       = T&;
   using const_reference = const T&;
 
-  _CCCL_HOST my_minimal_allocator() {}
+  _CCCL_HOST my_minimal_allocator() {} // NOLINT(modernize-use-equals-default)
 
   _CCCL_HOST my_minimal_allocator(const my_minimal_allocator& other)
       : use_me_to_alloc(other.use_me_to_alloc)
   {}
 
-  _CCCL_HOST ~my_minimal_allocator() {}
+  _CCCL_HOST ~my_minimal_allocator() {} // NOLINT(modernize-use-equals-default)
 
   value_type* allocate(std::ptrdiff_t n)
   {

thrust/testing/cuda/generate.cu

@@ -8,7 +8,7 @@ struct return_value
 {
   T val;
 
-  return_value() {}
+  return_value() = default;
   return_value(T v)
       : val(v)
   {}

thrust/testing/generate.cu

@@ -12,7 +12,7 @@ struct return_value
 {
   T val;
 
-  return_value() {}
+  return_value() = default;
   return_value(T v)
       : val(v)
   {}

thrust/testing/mr_pool.cu

@@ -42,7 +42,7 @@ struct tracked_pointer
       : ptr(ptr)
   {}
 
-  _CCCL_HOST_DEVICE ~tracked_pointer() {}
+  ~tracked_pointer() = default;
 
   template <typename U>
   operator tracked_pointer<U>() const

thrust/testing/out_of_memory_recovery.cu

@@ -18,8 +18,8 @@
 
 struct non_trivial
 {
-  _CCCL_HOST_DEVICE non_trivial() {}
-  _CCCL_HOST_DEVICE ~non_trivial() {}
+  _CCCL_HOST_DEVICE non_trivial() {} // NOLINT(modernize-use-equals-default)
+  _CCCL_HOST_DEVICE ~non_trivial() {} // NOLINT(modernize-use-equals-default)
 };
 
 void test_out_of_memory_recovery()