C++: Exclude copy assignment in LargeParameter.ql

cpp/ql/src/Critical/LargeParameter.ql

@@ -18,6 +18,7 @@ where f.getAParameter() = p
   and t.getSize() = size
   and size > 64
   and not t.getUnderlyingType() instanceof ArrayType
+  and not f instanceof CopyAssignmentOperator
 select
   p, "This parameter of type $@ is " + size.toString() + " bytes - consider passing a pointer/reference instead.",
   t, t.toString()

cpp/ql/test/query-tests/Critical/LargeParameter/test.cpp

@@ -44,3 +44,11 @@ void myFunction2(mySmallStruct *a, myLargeStruct *b) // GOOD
 void myFunction3(mySmallStruct &a, myLargeStruct &b) // GOOD
 {
 }
+
+struct CustomAssignmentOp {
+  // GOOD: it's an accepted pattern to implement copy assignment via copy and
+  // swap. This delegates the resource management involved in copying to the
+  // copy constructor so that logic only has to be written once.
+  CustomAssignmentOp &operator=(CustomAssignmentOp rhs);
+  char data[4096];
+};