Fixed #3875 (Static member method called with class name is considered unused)

lib/checkunusedfunctions.cpp

@@ -107,8 +107,15 @@ void CheckUnusedFunctions::parseTokens(const Tokenizer &tokenizer)
         else if (Token::Match(tok, "[;{}.,()[=+-/&|!?:] %var% [(),;:}]"))
             funcname = tok->next();
 
-        else if (Token::Match(tok, "[=(,] & %var% :: %var% [,);]"))
+        else if (Token::Match(tok, "[=(,] &| %var% :: %var%")) {
-            funcname = tok->tokAt(4);
+            funcname = tok->next();
+            if (funcname->str() == "&")
+                funcname = funcname->next();
+            while (Token::Match(funcname,"%var% :: %var%"))
+                funcname = funcname->tokAt(2);
+            if (!Token::Match(funcname, "%var% [,);]"))
+                continue;
+        }
 
         else
             continue;

test/testunusedfunctions.cpp

@@ -135,6 +135,17 @@ private:
               "    return 0\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check("namespace abc {\n"  // #3875
+              "void foo() { }\n"
+              "};\n"
+              "\n"
+              "int main()\n"
+              "{\n"
+              "    f(abc::foo);\n"
+              "    return 0\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void template1() {