Merge pull request #413 from jbj/return-this-getblock

C++: Restore `exists(getBlock())` in AV Rule 82

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

@@ -83,6 +83,7 @@ predicate assignOperatorWithWrongType(Operator op, string msg) {
 predicate assignOperatorWithWrongResult(Operator op, string msg) {
   op.hasName("operator=")
   and not returnsDereferenceThis(op)
+  and exists(op.getBlock())
   and not op.getType() instanceof VoidType
   and not assignOperatorWithWrongType(op, _)
   and msg = "Assignment operator in class " + op.getDeclaringType().getName() + " does not return a reference to *this."

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

@@ -171,6 +171,16 @@ class Reachability {
   static Reachability staticInstance;
 };
 
+class Forgivable {
+  // GOOD: wrong return type but that doesn't matter on a deleted function.
+  Forgivable operator=(const Forgivable &_val) = delete;
+
+private:
+  // GOOD: wrong return type but that doesn't matter because this operator is
+  // private and probably also unimplemented, so no code can call it.
+  Forgivable operator=(int *_val);
+};
+
 int main() {
   Container c;
   c = c;