add additional test cases

Author: a-tarasyuk

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

@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -fsyntax-only -Wunused-private-field -Wused-but-marked-unused -Wno-uninitialized -verify -std=c++11 %s
-// RUN: %clang_cc1 -fsyntax-only -Wunused-private-field -Wused-but-marked-unused -Wno-uninitialized -verify -std=c++17 %s
-// RUN: %clang_cc1 -fsyntax-only -Wunused-private-field -Wused-but-marked-unused -Wno-uninitialized -verify -std=c++20 %s
+// RUN: %clang_cc1 -fsyntax-only -Wunused -Wused-but-marked-unused -Wno-uninitialized -verify -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -Wunused -Wused-but-marked-unused -Wno-uninitialized -verify -std=c++17 %s
+// RUN: %clang_cc1 -fsyntax-only -Wunused -Wused-but-marked-unused -Wno-uninitialized -verify -std=c++20 %s
 
 #if __cplusplus >= 202002L
 
@@ -108,7 +108,7 @@ class ClassWithTemplateFriend {
 template <typename T> class TemplateFriend {
 public:
   TemplateFriend(ClassWithTemplateFriend my_friend) {
-    int var = my_friend.used_by_friend_;
+    int var = my_friend.used_by_friend_; // expected-warning {{unused variable 'var'}}
   }
 };
 
@@ -181,10 +181,10 @@ class EverythingUsed {
  public:
   EverythingUsed() : as_array_index_(0), var_(by_initializer_) {
     var_ = sizeof(sizeof_);
-    int *use = &by_reference_;
+    int *use = &by_reference_; // expected-warning {{unused variable 'use'}}
     int test[2];
     test[as_array_index_] = 42;
-    int EverythingUsed::*ptr = &EverythingUsed::by_pointer_to_member_;
+    int EverythingUsed::*ptr = &EverythingUsed::by_pointer_to_member_; // expected-warning {{unused variable 'ptr'}}
   }
 
   template<class T>
@@ -336,9 +336,21 @@ class [[gnu::warn_unused]] S {
   S();
 };
 
+struct [[maybe_unused]] T {};
+
+void f() {
+  int i = 0; // expected-warning {{unused variable 'i'}}
+  S s;       // expected-warning {{unused variable 's'}}
+  T t;       // ok
+}
+
 class C {
 private:
   const int i = 0; // expected-warning {{private field 'i' is not used}}
-  const S s;       // expected-warning {{private field 's' is not used}}
+  int j = 0;       // expected-warning {{private field 'j' is not used}}
+  const S s1;      // expected-warning {{private field 's1' is not used}}
+  const T t1;      // ok
+  S s2;            // expected-warning {{private field 's2' is not used}}
+  T t2;            // ok
 };
 }