fix #2569 check postfix increment on boolean

lib/checkother.cpp

@@ -34,6 +34,38 @@ CheckOther instance;
 
 //---------------------------------------------------------------------------
 
+void CheckOther::checkIncrementBoolean()
+{
+    if (!_settings->_checkCodingStyle)
+        return;
+
+    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
+    {
+        if (Token::Match(tok, "%var% ++"))
+        {
+            if (tok->varId())
+            {
+                const Token *declTok = Token::findmatch(_tokenizer->tokens(), "bool %varid%", tok->varId());
+                if (declTok)
+                    incrementBooleanError(tok);
+            }
+        }
+    }
+}
+
+void CheckOther::incrementBooleanError(const Token *tok)
+{
+    reportError(
+        tok,
+        Severity::style,
+        "incrementboolean",
+        "The use of a variable of type bool with the ++ postfix operator is always true and deprecated by the C++ Standard.\n"
+        "The operand of a postfix increment operator may be of type bool but it is deprecated by C++ Standard (Annex D-1) and the operand is always set to true\n"
+    );
+}
+
+//---------------------------------------------------------------------------
+
 
 void CheckOther::clarifyCalculation()
 {

lib/checkother.h

@@ -88,6 +88,7 @@ public:
         checkOther.checkCatchExceptionByValue();
         checkOther.checkMemsetZeroBytes();
         checkOther.checkIncorrectStringCompare();
+        checkOther.checkIncrementBoolean();
     }
 
     /** @brief Clarify calculation for ".. a * b ? .." */
@@ -184,6 +185,9 @@ public:
     /** @brief %Check for using bad usage of strncmp and substr */
     void checkIncorrectStringCompare();
 
+    /** @brief %Check for using postfix increment on bool */
+    void checkIncrementBoolean();
+
     // Error messages..
     void cstyleCastError(const Token *tok);
     void dangerousUsageStrtolError(const Token *tok);
@@ -209,6 +213,7 @@ public:
     void memsetZeroBytesError(const Token *tok, const std::string &varname);
     void sizeofForArrayParameterError(const Token *tok);
     void incorrectStringCompareError(const Token *tok, const std::string& func, const std::string &string, const std::string &len);
+    void incrementBooleanError(const Token *tok);
 
     void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings)
     {
@@ -249,6 +254,7 @@ public:
         c.memsetZeroBytesError(0, "varname");
         c.clarifyCalculationError(0);
         c.incorrectStringCompareError(0, "substr", "\"Hello World\"", "12");
+        c.incrementBooleanError(0);
     }
 
     std::string myName() const
@@ -289,6 +295,7 @@ public:
                "* mutual exclusion over || always evaluating to true\n"
                "* exception caught by value instead of by reference\n"
                "* Clarify calculation with parantheses\n"
+               "* using increment on boolean\n"
 
                // optimisations
                "* optimisation: detect post increment/decrement\n";

test/testother.cpp

@@ -104,6 +104,8 @@ private:
         TEST_CASE(clarifyCalculation);
 
         TEST_CASE(incorrectStringCompare);
+
+        TEST_CASE(incrementBoolean);
     }
 
     void check(const char code[], const char *filename = NULL)
@@ -141,6 +143,7 @@ private:
         checkOther.checkMemsetZeroBytes();
         checkOther.clarifyCalculation();
         checkOther.checkIncorrectStringCompare();
+        checkOther.checkIncrementBoolean();
     }
 
 
@@ -1892,6 +1895,23 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+
+    void incrementBoolean()
+    {
+        check("bool bValue = true;\n"
+              "bValue++;\n");
+        ASSERT_EQUALS("[test.cpp:2]: (style) The use of a variable of type bool with the ++ postfix operator is always true and deprecated by the C++ Standard.\n", errout.str());
+
+        check("void f(bool test){\n"
+              "    test++;\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:2]: (style) The use of a variable of type bool with the ++ postfix operator is always true and deprecated by the C++ Standard.\n", errout.str());
+
+        check("void f(int test){\n"
+              "    test++;\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+    }
 };
 
 REGISTER_TEST(TestOther)