Merge pull request #2604 from geoffw0/returnthis

CPP: Exclude template classes from cpp/assignment-does-not-return-this

cpp/ql/src/jsf/4.10 Classes/AV Rule 82.ql

@@ -93,6 +93,10 @@ predicate assignOperatorWithWrongResult(Operator op, string msg) {
 
 from Operator op, string msg
 where
-  assignOperatorWithWrongType(op, msg) or
-  assignOperatorWithWrongResult(op, msg)
+  (
+    assignOperatorWithWrongType(op, msg) or
+    assignOperatorWithWrongResult(op, msg)
+  ) and
+  // exclude code in templates which may be incomplete
+  not op.isFromUninstantiatedTemplate(_)
 select op, msg

cpp/ql/test/query-tests/jsf/4.10 Classes/AV Rule 82/AV Rule 82.cpp

@@ -201,6 +201,18 @@ struct TemplatedAssignmentBad {
   }
 };
 
+template<class T>
+class Obj3 {
+public:
+  Obj3<T> &subFunc(const Obj3<T> &other) {
+    return *this;
+  }
+
+  Obj3<T> &operator=(const Obj3<T> &other) {
+    return subFunc(other); // GOOD (returns *this)
+  }
+};
+
 int main() {
   Container c;
   c = c;
@@ -211,5 +223,7 @@ int main() {
   taGood = 3;
   TemplatedAssignmentBad taBad;
   taBad = 4;
+  Obj3<int> obj3_a, obj3_b;
+  obj3_a = obj3_b;
   return 0;
 }

cpp/ql/test/query-tests/jsf/4.10 Classes/AV Rule 82/AV Rule 82.expected

@@ -1,5 +1,4 @@
 | AV Rule 82.cpp:18:9:18:17 | operator= | Assignment operator in class Bad1 does not return a reference to *this. |
 | AV Rule 82.cpp:24:8:24:16 | operator= | Assignment operator in class Bad2 should have return type Bad2&. Otherwise a copy is created at each call. |
 | AV Rule 82.cpp:63:29:63:29 | operator= | Assignment operator in class TemplateReturnAssignment<int> does not return a reference to *this. |
-| AV Rule 82.cpp:63:29:63:37 | operator= | Assignment operator in class TemplateReturnAssignment<T> does not return a reference to *this. |
 | AV Rule 82.cpp:199:52:199:52 | operator= | Assignment operator in class TemplatedAssignmentBad should have return type TemplatedAssignmentBad&. Otherwise a copy is created at each call. |