#7370 False positive uselessCallsCompare on unknown type. Ensure related warnings are only issued on STL types

lib/checkstl.cpp

@@ -1253,15 +1253,24 @@ void CheckStl::uselessCalls()
         for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
             if (printWarning && Token::Match(tok, "%var% . compare|find|rfind|find_first_not_of|find_first_of|find_last_not_of|find_last_of ( %name% [,)]") &&
                 tok->varId() == tok->tokAt(4)->varId()) {
+                const Variable* var = tok->variable();
+                if (!var || !var->isStlType())
+                    continue;
                 uselessCallsReturnValueError(tok->tokAt(4), tok->str(), tok->strAt(2));
             } else if (printPerformance && Token::Match(tok, "%var% . swap ( %name% )") &&
                        tok->varId() == tok->tokAt(4)->varId()) {
+                const Variable* var = tok->variable();
+                if (!var || !var->isStlType())
+                    continue;
                 uselessCallsSwapError(tok, tok->str());
             } else if (printPerformance && Token::Match(tok, "%var% . substr (") &&
                        tok->variable() && tok->variable()->isStlStringType()) {
-                if (Token::Match(tok->tokAt(4), "0| )"))
+                if (Token::Match(tok->tokAt(4), "0| )")) {
+                    const Variable* var = tok->variable();
+                    if (!var || !var->isStlType())
+                        continue;
                     uselessCallsSubstrError(tok, false);
-                else if (tok->strAt(4) == "0" && tok->linkAt(3)->strAt(-1) == "npos") {
+                } else if (tok->strAt(4) == "0" && tok->linkAt(3)->strAt(-1) == "npos") {
                     if (!tok->linkAt(3)->previous()->variable()) // Make sure that its no variable
                         uselessCallsSubstrError(tok, false);
                 } else if (Token::simpleMatch(tok->linkAt(3)->tokAt(-2), ", 0 )"))

test/teststl.cpp

@@ -2498,11 +2498,19 @@ private:
               "    s1.swap(s2);\n"
               "    s2.swap(s2);\n"
               "};");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f()\n"
+              "{\n"
+              "    std::string s1, s2;\n"
+              "    s1.swap(s2);\n"
+              "    s2.swap(s2);\n"
+              "};");
         ASSERT_EQUALS("[test.cpp:5]: (performance) It is inefficient to swap a object with itself by calling 's2.swap(s2)'\n", errout.str());
 
         check("void f()\n"
               "{\n"
-              "    string s1, s2;\n"
+              "    std::string s1, s2;\n"
               "    s1.compare(s2);\n"
               "    s2.compare(s2);\n"
               "    s1.compare(s2.c_str());\n"
@@ -2510,6 +2518,17 @@ private:
               "};");
         ASSERT_EQUALS("[test.cpp:5]: (warning) It is inefficient to call 's2.compare(s2)' as it always returns 0.\n", errout.str());
 
+        // #7370 False positive uselessCallsCompare on unknown type
+        check("class ReplayIteratorImpl{\n"
+              "  int Compare(ReplayIteratorImpl* other) {\n"
+              "    int cmp;\n"
+              "    int ret = cursor_->compare(cursor_, other->cursor_, &cmp);\n"
+              "    return (cmp);\n"
+              "  }\n"
+              "  WT_CURSOR *cursor_;\n"
+              "};");
+        ASSERT_EQUALS("", errout.str());
+
         check("void f()\n"
               "{\n"
               "    int x=1;\n"
@@ -2566,6 +2585,7 @@ private:
         ASSERT_EQUALS("", errout.str());
 
         check("void f() {\n"
+              "    std::vector<int> a;\n"
               "    std::remove(a.begin(), a.end(), val);\n"
               "    std::remove_if(a.begin(), a.end(), val);\n"
               "    std::unique(a.begin(), a.end(), val);\n"
@@ -2573,9 +2593,9 @@ private:
               "    a.erase(std::remove(a.begin(), a.end(), val));\n"
               "    std::remove(\"foo.txt\");\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:2]: (warning) Return value of std::remove() ignored. Elements remain in container.\n"
+        ASSERT_EQUALS("[test.cpp:3]: (warning) Return value of std::remove() ignored. Elements remain in container.\n"
-                      "[test.cpp:3]: (warning) Return value of std::remove_if() ignored. Elements remain in container.\n"
+                      "[test.cpp:4]: (warning) Return value of std::remove_if() ignored. Elements remain in container.\n"
-                      "[test.cpp:4]: (warning) Return value of std::unique() ignored. Elements remain in container.\n", errout.str());
+                      "[test.cpp:5]: (warning) Return value of std::unique() ignored. Elements remain in container.\n", errout.str());
 
         // #4431 - fp
         check("bool f() {\n"