Fixed false positive: Support assignments in CheckStl::if_find()

lib/checkstl.cpp

@@ -743,11 +743,13 @@ static bool if_findCompare(const Token * const tokBack)
 {
     const Token *tok = tokBack->astParent();
     if (!tok)
-        return false;
+        return true;
     if (tok->isComparisonOp())
         return true;
     if (tok->isArithmeticalOp()) // result is used in some calculation
         return true;  // TODO: check if there is a comparison of the result somewhere
+    if (tok->isAssignmentOp())
+        return if_findCompare(tok); // Go one step upwards in the AST
     return false;
 }
 

test/teststl.cpp

@@ -1497,6 +1497,13 @@ private:
               "}");
         ASSERT_EQUALS("[test.cpp:3]: (warning) Suspicious condition. The result of find() is an iterator, but it is not properly checked.\n", errout.str());
 
+        // error (assignment)
+        check("void f(std::set<int> s)\n"
+              "{\n"
+              "    if (a || (x = s.find(12))) { }\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:3]: (warning) Suspicious condition. The result of find() is an iterator, but it is not properly checked.\n", errout.str());
+
         // ok (simple)
         check("void f(std::set<int> s)\n"
               "{\n"
@@ -1539,6 +1546,13 @@ private:
               "}");
         ASSERT_EQUALS("", errout.str());
 
+        // ok (assignment)
+        check("void f(std::set<int> s)\n"
+              "{\n"
+              "    if (a || (x = s.find(12)) != s.end()) { }\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+
 
         // ---------------------------
         // std::find