C++: Demonstrate false positives when a const variable is initialized in a parameter list

MathiasVP · MathiasVP · commit cc25298f673d · 2020-03-13T17:00:54.000+01:00
diff --git a/cpp/ql/test/query-tests/Likely Bugs/Arithmetic/PointlessComparison/PointlessComparison.cpp b/cpp/ql/test/query-tests/Likely Bugs/Arithmetic/PointlessComparison/PointlessComparison.cpp
@@ -0,0 +1,29 @@
+void func_with_default_arg(const int n = 0) {
+    if(n <= 10) {} // GOOD [FALSE POSITIVE]
+}
+
+struct A {
+    const int int_member = 0;
+    A(int n) : int_member(n) {
+        if(int_member <= 10) {
+                    
+        }
+    }
+};
+
+struct B {
+    B(const int n = 0) {
+        if(n <= 10) {} // GOOD [FALSE POSITIVE]
+    }
+};
+
+const volatile int volatile_const_global = 0;
+
+void test1() {
+    func_with_default_arg(100);
+
+    A a(100);
+    if(a.int_member <= 10) {}
+
+    if(volatile_const_global <= 10) {} // GOOD [FALSE POSITIVE]
+}
diff --git a/cpp/ql/test/query-tests/Likely Bugs/Arithmetic/PointlessComparison/PointlessComparison.expected b/cpp/ql/test/query-tests/Likely Bugs/Arithmetic/PointlessComparison/PointlessComparison.expected
@@ -38,5 +38,8 @@
 | PointlessComparison.c:303:9:303:14 | ... >= ... | Comparison is always false because c <= 0. |
 | PointlessComparison.c:312:9:312:14 | ... >= ... | Comparison is always false because c <= 0. |
 | PointlessComparison.c:337:14:337:21 | ... >= ... | Comparison is always true because x >= 0. |
+| PointlessComparison.cpp:2:8:2:14 | ... <= ... | Comparison is always true because n <= 0. |
+| PointlessComparison.cpp:16:12:16:18 | ... <= ... | Comparison is always true because n <= 0. |
+| PointlessComparison.cpp:28:8:28:34 | ... <= ... | Comparison is always true because volatile_const_global <= 0. |
 | RegressionTests.cpp:57:7:57:22 | ... <= ... | Comparison is always true because * ... <= 4294967295. |
 | Templates.cpp:9:10:9:24 | ... <= ... | Comparison is always true because local <= 32767. |
