Cleanups: Friendship is magic (#3524)

stl/inc/bitset

@@ -29,7 +29,7 @@ public:
 #pragma warning(pop)
 
     class reference { // proxy for an element
-        friend bitset<_Bits>;
+        friend bitset;
 
     public:
         _CONSTEXPR23 reference(const reference&) = default;

stl/inc/exception

@@ -135,6 +135,8 @@ protected:
     }
 };
 
+class bad_array_new_length;
+
 class bad_alloc : public exception { // base of all bad allocation exceptions
 public:
     __CLR_OR_THIS_CALL bad_alloc() noexcept
@@ -143,7 +145,7 @@ public:
     __CLR_OR_THIS_CALL ~bad_alloc() noexcept override {}
 
 private:
-    friend class bad_array_new_length;
+    friend bad_array_new_length;
 
     __CLR_OR_THIS_CALL bad_alloc(const char* _Message) noexcept
         : exception(_Message, 1) {} // construct from message string with no memory allocation

stl/inc/filesystem

@@ -2080,6 +2080,9 @@ namespace filesystem {
     using file_time_type = _CHRONO time_point<filesystem::_File_time_clock>;
 #endif // ^^^ !_HAS_CXX20
 
+    struct _Dir_enum_impl;
+    struct _Recursive_dir_enum_impl;
+
     _EXPORT_STD class directory_entry {
     public:
         // [fs.dir.entry.cons], constructors and destructor
@@ -2472,8 +2475,8 @@ namespace filesystem {
             return _Error;
         }
 
-        friend struct _Dir_enum_impl;
-        friend struct _Recursive_dir_enum_impl;
+        friend _Dir_enum_impl;
+        friend _Recursive_dir_enum_impl;
         friend void _Copy_impl(
             const directory_entry& _From, const _STD filesystem::path& _To, copy_options _Options, error_code& _Ec);
 

stl/inc/ranges

@@ -2330,9 +2330,6 @@ namespace ranges {
         /* [[no_unique_address]] */ _Vw _Range{};
         /* [[no_unique_address]] */ _Movable_box<_Fn> _Fun{};
 
-        template <bool _Const>
-        class _Sentinel;
-
         template <bool _Const>
         struct _Category_base {};
 
@@ -2350,10 +2347,7 @@ namespace ranges {
         template <bool _Const>
         class _Iterator : public _Category_base<_Const> {
         private:
-            template <bool>
-            friend class _Iterator;
-            template <bool>
-            friend class _Sentinel;
+            friend transform_view;
 
             using _Parent_t = _Maybe_const<_Const, transform_view>;
             using _Base     = _Maybe_const<_Const, _Vw>;
@@ -2603,8 +2597,7 @@ namespace ranges {
         template <bool _Const>
         class _Sentinel {
         private:
-            template <bool>
-            friend class _Sentinel;
+            friend transform_view;
 
             using _Parent_t = _Maybe_const<_Const, transform_view>;
             using _Base     = _Maybe_const<_Const, _Vw>;
@@ -2776,8 +2769,7 @@ namespace ranges {
         template <bool _Const, bool _Wrapped = true>
         class _Sentinel {
         private:
-            template <bool, bool>
-            friend class _Sentinel;
+            friend take_view;
 
             using _Base_t        = _Maybe_const<_Const, _Vw>;
             using _Base_sentinel = _Maybe_wrapped<_Wrapped, sentinel_t<_Base_t>>;
@@ -3070,8 +3062,7 @@ namespace ranges {
         template <bool _Const, bool _Wrapped = true>
         class _Sentinel {
         private:
-            template <bool, bool>
-            friend class _Sentinel;
+            friend take_while_view;
 
             using _Base_t        = _Maybe_const<_Const, _Vw>;
             using _Base_iterator = _Maybe_wrapped<_Wrapped, iterator_t<_Base_t>>;
@@ -4562,9 +4553,7 @@ namespace ranges {
         template <bool _Const>
         class _Outer_iter : public _Outer_iter_base<iterator_t<_Maybe_const<_Const, _Vw>>> {
         private:
-            template <bool>
-            friend class _Inner_iter;
-            friend _Outer_iter<true>;
+            friend lazy_split_view;
 
             using _Mybase   = _Outer_iter_base<iterator_t<_Maybe_const<_Const, _Vw>>>;
             using _ParentTy = _Maybe_const<_Const, lazy_split_view>;
@@ -4934,11 +4923,9 @@ namespace ranges {
         /* [[no_unique_address]] */ _Pat _Pattern{};
         _Non_propagating_cache<subrange<iterator_t<_Vw>>> _Next{};
 
-        class _Sentinel;
-
         class _Iterator {
         private:
-            friend _Sentinel;
+            friend split_view;
 
             split_view* _Parent             = nullptr;
             iterator_t<_Vw> _Current        = {};
@@ -5601,9 +5588,6 @@ namespace ranges {
     private:
         /* [[no_unique_address]] */ _Vw _Range{};
 
-        template <bool _Const>
-        class _Sentinel;
-
         template <class _Base>
         struct _Category_base {};
 
@@ -5619,10 +5603,7 @@ namespace ranges {
         template <bool _Const>
         class _Iterator : public _Category_base<_Maybe_const<_Const, _Vw>> {
         private:
-            template <bool>
-            friend class _Iterator;
-            template <bool>
-            friend class _Sentinel;
+            friend elements_view;
 
             using _Base = _Maybe_const<_Const, _Vw>;
 
@@ -5850,8 +5831,7 @@ namespace ranges {
         template <bool _Const>
         class _Sentinel {
         private:
-            template <bool>
-            friend class _Sentinel;
+            friend elements_view;
 
             using _Base = _Maybe_const<_Const, _Vw>;
             template <bool _OtherConst>
@@ -6359,10 +6339,9 @@ namespace ranges {
         range_difference_t<_Vw> _Remainder = 0;
         _Non_propagating_cache<iterator_t<_Vw>> _Current{};
 
-        class _Outer_iterator;
         class _Inner_iterator {
         private:
-            friend struct _Outer_iterator::value_type;
+            friend chunk_view;
             chunk_view* _Parent{};
 
             constexpr explicit _Inner_iterator(chunk_view* _Parent_) noexcept : _Parent(_Parent_) {}

stl/inc/xlocale

@@ -115,12 +115,12 @@ public:
         __PURE_APPDOMAIN_GLOBAL static int _Id_cnt;
     };
 
-    class _Locimp;
+    struct _Facet_guard;
 
     class _CRTIMP2_PURE_IMPORT facet : public _Facet_base, public _Crt_new_delete {
         // base class for all locale facets, performs reference counting
     private:
-        friend struct _Facet_guard;
+        friend _Facet_guard;
 
     public:
         static size_t __CLRCALL_OR_CDECL _Getcat(const facet** = nullptr, const locale* = nullptr) {