Fixed #3336 (False positive: Member function is not used (used by template function))

lib/checkunusedfunctions.cpp

@@ -33,6 +33,11 @@
 
 void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer)
 {
+    // if there are templates there might be false positives
+    templates |= tokenizer.codeWithTemplates();
+    if (templates)
+        return;
+
     // Function declarations..
     for (const Token *tok = tokenizer.tokens(); tok; tok = tok->next()) {
         if (tok->fileIndex() != 0)
@@ -144,6 +149,9 @@ void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer)
 
 void CheckUnusedFunctions::check(ErrorLogger * const errorLogger)
 {
+    if (templates)
+        return;
+
     for (std::map<std::string, FunctionUsage>::const_iterator it = _functions.begin(); it != _functions.end(); ++it) {
         const FunctionUsage &func = it->second;
         if (func.usedOtherFile || func.filename.empty())

lib/checkunusedfunctions.h

@@ -32,12 +32,12 @@
 class CheckUnusedFunctions: public Check {
 public:
     /** @brief This constructor is used when registering the CheckUnusedFunctions */
-    CheckUnusedFunctions() : Check(myName())
+    CheckUnusedFunctions() : Check(myName()), templates(false)
     { }
 
     /** @brief This constructor is used when running checks. */
     CheckUnusedFunctions(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
-        : Check(myName(), tokenizer, settings, errorLogger)
+        : Check(myName(), tokenizer, settings, errorLogger), templates(false)
     { }
 
     // Parse current tokens and determine..
@@ -88,6 +88,8 @@ private:
     };
 
     std::map<std::string, FunctionUsage> _functions;
+
+    bool templates;
 };
 /// @}
 //---------------------------------------------------------------------------

test/testunusedfunctions.cpp

@@ -40,6 +40,7 @@ private:
         TEST_CASE(else1);
         TEST_CASE(functionpointer);
         TEST_CASE(template1);
+        TEST_CASE(template2);
         TEST_CASE(throwIsNotAFunction);
         TEST_CASE(unusedError);
         TEST_CASE(unusedMain);
@@ -146,6 +147,16 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void template2() {
+        check("void f() { }\n"
+              "\n"
+              "template<class T> void g()\n"
+              "{\n"
+              "    f();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void throwIsNotAFunction() {
         check("struct A {void f() const throw () {}}; int main() {A a; a.f();}\n");
         ASSERT_EQUALS("", errout.str());