Address review comments

Author: whiteio

clang/lib/Sema/SemaDeclCXX.cpp

@@ -7535,8 +7535,15 @@ void Sema::CheckExplicitlyDefaultedFunction(Scope *S, FunctionDecl *FD) {
     return;
   }
 
-  if (DefKind.isComparison() && isa<CXXRecordDecl>(FD->getDeclContext()))
-    UnusedPrivateFields.clear();
+  if (DefKind.isComparison()) {
+    auto PT = FD->getParamDecl(0)->getType();
+    if (const CXXRecordDecl *RD =
+            PT.getNonReferenceType()->getAsCXXRecordDecl()) {
+      for (FieldDecl *Field : RD->fields()) {
+        UnusedPrivateFields.remove(Field);
+      }
+    }
+  }
 
   if (DefKind.isSpecialMember()
           ? CheckExplicitlyDefaultedSpecialMember(cast<CXXMethodDecl>(FD),

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

@@ -41,16 +41,26 @@ class FriendEqDefaultCompareOutOfClass {
 bool operator==(const FriendEqDefaultCompareOutOfClass &, const FriendEqDefaultCompareOutOfClass &) = default;
 
 class UnusedConstPrivateField {
- public:
-  UnusedConstPrivateField() : unused_(0) {}
- private:
-  const int unused_; // expected-warning{{private field 'unused_' is not used}}
+public:
+    UnusedConstPrivateField() : unused_(0) {}
+private:
+    const int unused_; // expected-warning{{private field 'unused_' is not used}}
+};
+
+class HasUnusedField {
+  int unused_; // expected-warning{{private field 'unused_' is not used}}
 };
 
 class FriendEqDefaultCompare {
+  int used;
   friend auto operator==(FriendEqDefaultCompare, FriendEqDefaultCompare) -> bool = default;
 };
 
+class UnrelatedFriendEqDefaultCompare {
+  friend auto operator==(UnrelatedFriendEqDefaultCompare, UnrelatedFriendEqDefaultCompare) -> bool = default;
+  int operator<=>(const UnrelatedFriendEqDefaultCompare &) const = default;
+};
+
 #endif
 
 class NotFullyDefined {