Fix ticket #2233 (unused private static function)

lib/checkclass.cpp

@@ -619,10 +619,12 @@ void CheckClass::privateFunctions()
             // eg. sigc::mem_fun(this, &className::classFunction)
             const std::string _pattern2("& " + classname + " :: " + FuncList.front()->str());
             const std::string methodAsArgument("(|, " + classname + " :: " + FuncList.front()->str() + " ,|)");
+            const std::string methodAssigned("%var% = &| " + classname + " :: " + FuncList.front()->str());
+
             if (!Token::findmatch(_tokenizer->tokens(), _pattern.c_str()) &&
                 !Token::findmatch(_tokenizer->tokens(), _pattern2.c_str()) &&
-                !Token::findmatch(_tokenizer->tokens(), methodAsArgument.c_str())
+                !Token::findmatch(_tokenizer->tokens(), methodAsArgument.c_str()) &&
-               ) {
+                !Token::findmatch(_tokenizer->tokens(), methodAssigned.c_str())) {
                 unusedPrivateFunctionError(FuncList.front(), classname, FuncList.front()->str());
             }
             FuncList.pop_front();

test/testclass.cpp

@@ -207,6 +207,7 @@ private:
         TEST_CASE(constUnion);	// ticket #2111 - fp when there are union
 
         TEST_CASE(initializerList);
+        TEST_CASE(unusedPrivate); // ticket #2233
     }
 
     // Check the operator Equal
@@ -6386,6 +6387,35 @@ private:
                       "[test.cpp:4] -> [test.cpp:2]: (style) Member variable 'Fred::a' is in the wrong order in the initializer list.\n", errout.str());
     }
 
+    void check(const char code[]) {
+        // Clear the error buffer..
+        errout.str("");
+
+        Settings settings;
+        settings.addEnabled("style");
+        settings.inconclusive = true;
+
+        // Tokenize..
+        Tokenizer tokenizer(&settings, this);
+        std::istringstream istr(code);
+        tokenizer.tokenize(istr, "test.cpp");
+
+        // Check..
+        CheckClass checkClass(&tokenizer, &settings, this);
+        checkClass.runSimplifiedChecks(&tokenizer, &settings, this);
+    }
+
+    void unusedPrivate() {
+        check("class A {\n"
+                   "public:\n"
+                   "    A() { f = A::func; }\n"
+                   "    void (*f)();\n"
+                   "private:\n"
+                   "    static void func() { }\n"
+                   "};\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
 };
 
 REGISTER_TEST(TestClass)