Add Release Notes and comments to test

Author: Maetveis

clang/docs/ReleaseNotes.rst

@@ -585,6 +585,8 @@ Improvements to Clang's diagnostics
 - For an rvalue reference bound to a temporary struct with an integer member, Clang will detect constant integer overflow
   in the initializer for the integer member (#GH46755).
 
+- Fixed a false negative ``-Wunused-private-field`` diagnostic when a defaulted comparison operator is defined out of class (#GH116961).
+
 Improvements to Clang's time-trace
 ----------------------------------
 

clang/test/SemaCXX/warn-unused-private-field.cpp

@@ -21,14 +21,14 @@ class SpaceShipDefaultCompare {
 };
 
 class EqDefaultCompareOutOfClass {
-  int used;
+  int used; // no warning
   bool operator==(const EqDefaultCompareOutOfClass &) const;
 };
 
 bool EqDefaultCompareOutOfClass::operator==(const EqDefaultCompareOutOfClass &) const = default;
 
 class FriendEqDefaultCompareOutOfClass {
-  int used;
+  int used; // no warning
   friend bool operator==(const FriendEqDefaultCompareOutOfClass &, const FriendEqDefaultCompareOutOfClass &);
 };