Fixed #2154 (false positive: The loop might unintentionally skip an element in the container)

lib/checkstl.cpp

@@ -880,6 +880,9 @@ void CheckStl::missingComparison()
                 }
 
                 const unsigned int &iteratorId(tok2->varId());
+                if (iteratorId == 0)
+                    continue;
+
                 const Token *incrementToken = 0;
                 unsigned int indentlevel = 0;
                 // Parse loop..

test/teststl.cpp

@@ -99,6 +99,7 @@ private:
         TEST_CASE(missingInnerComparison2);     // no FP when there is comparison
         TEST_CASE(missingInnerComparison3);     // no FP when there is iterator shadowing
         TEST_CASE(missingInnerComparison4);     // no FP when "break;" is used
+        TEST_CASE(missingInnerComparison5);     // Ticket #2154 - FP
 
         // catch common problems when using the string::c_str() function
         TEST_CASE(cstr);
@@ -1108,6 +1109,16 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    void missingInnerComparison5()
+    {
+        check("void f() {\n"
+              "    for(it = map1.begin(); it != map1.end(); it++) {\n"
+              "        str[i++] = (*it).first;\n"
+              "    }\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void cstr()
     {
         check("void f() {\n"