diff --git a/libcxx/include/__functional/function.h b/libcxx/include/__functional/function.h
--- a/libcxx/include/__functional/function.h
+++ b/libcxx/include/__functional/function.h
@@ -1664,7 +1664,7 @@
 
 #endif // _LIBCPP_NO_RTTI
 
-}  // __function
+} // namespace __function
 
 template<class _Rp>
 class _LIBCPP_TEMPLATE_VIS function<_Rp()>
diff --git a/libcxx/include/__ranges/access.h b/libcxx/include/__ranges/access.h
--- a/libcxx/include/__ranges/access.h
+++ b/libcxx/include/__ranges/access.h
@@ -83,7 +83,7 @@
 
     void operator()(auto&&) const = delete;
   };
-}
+} // namespace __begin
 
 inline namespace __cpo {
   inline constexpr auto begin = __begin::__fn{};
@@ -150,7 +150,7 @@
 
     void operator()(auto&&) const = delete;
   };
-}
+} // namespace __end
 
 inline namespace __cpo {
   inline constexpr auto end = __end::__fn{};
@@ -178,7 +178,7 @@
       -> decltype(      ranges::begin(static_cast<const _Tp&&>(__t)))
       { return          ranges::begin(static_cast<const _Tp&&>(__t)); }
   };
-}
+} // namespace __cbegin
 
 inline namespace __cpo {
   inline constexpr auto cbegin = __cbegin::__fn{};
@@ -206,7 +206,7 @@
       -> decltype(      ranges::end(static_cast<const _Tp&&>(__t)))
       { return          ranges::end(static_cast<const _Tp&&>(__t)); }
   };
-}
+} // namespace __cend
 
 inline namespace __cpo {
   inline constexpr auto cend = __cend::__fn{};
diff --git a/libcxx/include/__ranges/all.h b/libcxx/include/__ranges/all.h
--- a/libcxx/include/__ranges/all.h
+++ b/libcxx/include/__ranges/all.h
@@ -64,7 +64,7 @@
       return ranges::owning_view{_VSTD::forward<_Tp>(__t)};
     }
   };
-}
+} // namespace __all
 
 inline namespace __cpo {
   inline constexpr auto all = __all::__fn{};
diff --git a/libcxx/include/__ranges/common_view.h b/libcxx/include/__ranges/common_view.h
--- a/libcxx/include/__ranges/common_view.h
+++ b/libcxx/include/__ranges/common_view.h
@@ -120,11 +120,11 @@
       -> decltype(      common_view{_VSTD::forward<_Range>(__range)})
       { return          common_view{_VSTD::forward<_Range>(__range)}; }
   };
-}
+} // namespace __common
 
 inline namespace __cpo {
   inline constexpr auto common = __common::__fn{};
-}
+} // namespace __cpo
 } // namespace views
 } // namespace ranges
 
diff --git a/libcxx/include/__ranges/data.h b/libcxx/include/__ranges/data.h
--- a/libcxx/include/__ranges/data.h
+++ b/libcxx/include/__ranges/data.h
@@ -64,7 +64,7 @@
       return _VSTD::to_address(ranges::begin(__t));
     }
   };
-}
+} // namespace __data
 
 inline namespace __cpo {
   inline constexpr auto data = __data::__fn{};
@@ -92,7 +92,7 @@
       -> decltype(      ranges::data(static_cast<const _Tp&&>(__t)))
       { return          ranges::data(static_cast<const _Tp&&>(__t)); }
   };
-}
+} // namespace __cdata
 
 inline namespace __cpo {
   inline constexpr auto cdata = __cdata::__fn{};
diff --git a/libcxx/include/__ranges/empty.h b/libcxx/include/__ranges/empty.h
--- a/libcxx/include/__ranges/empty.h
+++ b/libcxx/include/__ranges/empty.h
@@ -68,7 +68,7 @@
       return ranges::begin(__t) == ranges::end(__t);
     }
   };
-}
+} // namespace __empty
 
 inline namespace __cpo {
   inline constexpr auto empty = __empty::__fn{};
diff --git a/libcxx/include/__ranges/iota_view.h b/libcxx/include/__ranges/iota_view.h
--- a/libcxx/include/__ranges/iota_view.h
+++ b/libcxx/include/__ranges/iota_view.h
@@ -397,7 +397,7 @@
 
 inline namespace __cpo {
   inline constexpr auto iota = __iota::__fn{};
-}
+} // namespace __cpo
 } // namespace views
 } // namespace ranges
 
diff --git a/libcxx/include/__ranges/reverse_view.h b/libcxx/include/__ranges/reverse_view.h
--- a/libcxx/include/__ranges/reverse_view.h
+++ b/libcxx/include/__ranges/reverse_view.h
@@ -175,11 +175,11 @@
         -> decltype(      reverse_view{_VSTD::forward<_Range>(__range)})
         { return          reverse_view{_VSTD::forward<_Range>(__range)}; }
     };
-  }
+  } // namespace __reverse
 
   inline namespace __cpo {
     inline constexpr auto reverse = __reverse::__fn{};
-  }
+  } // namespace __cpo
   } // namespace views
 } // namespace ranges
 
diff --git a/libcxx/include/__ranges/size.h b/libcxx/include/__ranges/size.h
--- a/libcxx/include/__ranges/size.h
+++ b/libcxx/include/__ranges/size.h
@@ -29,7 +29,7 @@
 namespace ranges {
   template<class>
   inline constexpr bool disable_sized_range = false;
-}
+} // namespace ranges
 
 // [range.prim.size]
 
@@ -97,7 +97,7 @@
       return _VSTD::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t));
     }
   };
-}
+} // namespace __size
 
 inline namespace __cpo {
   inline constexpr auto size = __size::__fn{};
@@ -121,7 +121,7 @@
         return static_cast<_Signed>(ranges::size(__t));
     }
   };
-}
+} // namespace __ssize
 
 inline namespace __cpo {
   inline constexpr auto ssize = __ssize::__fn{};
diff --git a/libcxx/include/__ranges/transform_view.h b/libcxx/include/__ranges/transform_view.h
--- a/libcxx/include/__ranges/transform_view.h
+++ b/libcxx/include/__ranges/transform_view.h
@@ -424,11 +424,11 @@
       noexcept(is_nothrow_constructible_v<decay_t<_Fn>, _Fn>)
     { return __range_adaptor_closure_t(_VSTD::__bind_back(*this, _VSTD::forward<_Fn>(__f))); }
   };
-}
+} // namespace __transform
 
 inline namespace __cpo {
   inline constexpr auto transform = __transform::__fn{};
-}
+} // namespace __cpo
 } // namespace views
 
 } // namespace ranges
diff --git a/libcxx/include/__ranges/view_interface.h b/libcxx/include/__ranges/view_interface.h
--- a/libcxx/include/__ranges/view_interface.h
+++ b/libcxx/include/__ranges/view_interface.h
@@ -186,7 +186,7 @@
   }
 };
 
-}
+} // namespace ranges
 
 #endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
 
diff --git a/libcxx/include/cstddef b/libcxx/include/cstddef
--- a/libcxx/include/cstddef
+++ b/libcxx/include/cstddef
@@ -156,7 +156,8 @@
 template <class _Integer, class = _EnableByteOverload<_Integer> >
   _LIBCPP_NODISCARD_EXT constexpr _Integer
   to_integer(byte __b) noexcept { return static_cast<_Integer>(__b); }
-}
+
+} // namespace std
 
 #endif
 
diff --git a/libcxx/include/variant b/libcxx/include/variant
--- a/libcxx/include/variant
+++ b/libcxx/include/variant
@@ -1252,7 +1252,7 @@
 using __best_match_t =
     typename invoke_result_t<_MakeOverloads<_Types...>, _Tp, _Tp>::type;
 
-} // __variant_detail
+} // namespace __variant_detail
 
 template <class... _Types>
 class _LIBCPP_TEMPLATE_VIS variant