CTR55-CPP: improve testfile to doc an expected fp corner case

Author: knewbury01

cpp/cert/test/rules/CTR55-CPP/DoNotUseAnAdditiveOperatorOnAnIterator.expected

@@ -5,3 +5,4 @@
 | test.cpp:28:31:28:31 | i | Increment of iterator may overflow since its bounds are not checked. |
 | test.cpp:41:5:41:8 | end2 | Increment of iterator may overflow since its bounds are not checked. |
 | test.cpp:53:42:53:42 | i | Increment of iterator may overflow since its bounds are not checked. |
+| test.cpp:64:15:64:15 | i | Increment of iterator may overflow since its bounds are not checked. |

cpp/cert/test/rules/CTR55-CPP/test.cpp

@@ -53,4 +53,14 @@ void test(std::vector<int> &v, std::vector<int> &v2) {
     for (auto i = v.begin(); i != end; ++i) { // NON_COMPLIANT - wrong check
     }
   }
+}
+
+void test2(std::vector<int> &v) {
+  auto i = v.begin();
+  while (1) {
+    auto i2 = ((i != v.end()) != 0);
+    if (!i2)
+      break;
+    (void)((++i)); // COMPLIANT[FALSE_POSITIVE]
+  }
 }