Improved CheckOther::checkUnusedLabel(): Write a warning instead of a style message if it happens inside a switch()

Author: PKEuS

lib/checkother.cpp

@@ -2481,7 +2481,7 @@ void CheckOther::raceAfterInterlockedDecrementError(const Token* tok)
 
 void CheckOther::checkUnusedLabel()
 {
-    if (!_settings->isEnabled("style"))
+    if (!_settings->isEnabled("style") && !_settings->isEnabled("warning"))
         return;
 
     const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
@@ -2495,16 +2495,23 @@ void CheckOther::checkUnusedLabel()
 
             if (Token::Match(tok, "{|}|; %name% :") && tok->strAt(1) != "default") {
                 if (!Token::findsimplematch(scope->classStart->next(), ("goto " + tok->strAt(1)).c_str(), scope->classEnd->previous()))
-                    unusedLabelError(tok->next());
+                    unusedLabelError(tok->next(), tok->scope()->type == Scope::eSwitch);
             }
         }
     }
 }
 
-void CheckOther::unusedLabelError(const Token* tok)
+void CheckOther::unusedLabelError(const Token* tok, bool inSwitch)
 {
-    reportError(tok, Severity::style, "unusedLabel",
-                "Label '" + (tok?tok->str():emptyString) + "' is not used.");
+    if (inSwitch) {
+        if (!tok || _settings->isEnabled("warning"))
+            reportError(tok, Severity::warning, "unusedLabelSwitch",
+                        "Label '" + (tok ? tok->str() : emptyString) + "' is not used. Should this be a 'case' of the enclosing switch()?");
+    } else {
+        if (!tok || _settings->isEnabled("style"))
+            reportError(tok, Severity::style, "unusedLabel",
+                        "Label '" + (tok ? tok->str() : emptyString) + "' is not used.");
+    }
 }
 
 

lib/checkother.h

@@ -254,7 +254,7 @@ class CPPCHECKLIB CheckOther : public Check {
     void commaSeparatedReturnError(const Token *tok);
     void redundantPointerOpError(const Token* tok, const std::string& varname, bool inconclusive);
     void raceAfterInterlockedDecrementError(const Token* tok);
-    void unusedLabelError(const Token* tok);
+    void unusedLabelError(const Token* tok, bool inSwitch);
     void unknownEvaluationOrder(const Token* tok);
 
     void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
@@ -309,7 +309,8 @@ class CPPCHECKLIB CheckOther : public Check {
         c.nanInArithmeticExpressionError(0);
         c.commaSeparatedReturnError(0);
         c.redundantPointerOpError(0, "varname", false);
-        c.unusedLabelError(0);
+        c.unusedLabelError(0, true);
+        c.unusedLabelError(0, false);
         c.unknownEvaluationOrder(0);
     }
 

test/testother.cpp

@@ -6108,6 +6108,19 @@ class TestOther : public TestFixture {
               "    };\n"
               "}");
         ASSERT_EQUALS("", errout.str());
+
+        check("int test(char art) {\n"
+              "    switch (art) {\n"
+              "    caseZERO:\n"
+              "        return 0;\n"
+              "    case1:\n"
+              "        return 1;\n"
+              "    case 2:\n"
+              "        return 2;\n"
+              "    }\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:3]: (warning) Label 'caseZERO' is not used. Should this be a 'case' of the enclosing switch()?\n"
+                      "[test.cpp:5]: (warning) Label 'case1' is not used. Should this be a 'case' of the enclosing switch()?\n", errout.str());
     }
 
     void testEvaluationOrder() {