C++: Add a TODO comment.

Author: geoffw0

cpp/ql/src/semmle/code/cpp/models/implementations/MemberFunction.qll

@@ -13,7 +13,7 @@ class ConversionConstructorModel extends ConversionConstructor, TaintFunction {
   override predicate hasTaintFlow(FunctionInput input, FunctionOutput output) {
     // taint flow from the first constructor argument to the returned object
     input.isParameter(0) and
-    output.isReturnValue()
+    output.isReturnValue() // TODO: this should be `isQualifierObject` by our current definitions, but that flow is not yet supported.
   }
 }
 
@@ -24,7 +24,7 @@ class CopyConstructorModel extends CopyConstructor, DataFlowFunction {
   override predicate hasDataFlow(FunctionInput input, FunctionOutput output) {
     // data flow from the first constructor argument to the returned object
     input.isParameter(0) and
-    output.isReturnValue()
+    output.isReturnValue() // TODO: this should be `isQualifierObject` by our current definitions, but that flow is not yet supported.
   }
 }
 
@@ -35,7 +35,7 @@ class MoveConstructorModel extends MoveConstructor, DataFlowFunction {
   override predicate hasDataFlow(FunctionInput input, FunctionOutput output) {
     // data flow from the first constructor argument to the returned object
     input.isParameter(0) and
-    output.isReturnValue()
+    output.isReturnValue() // TODO: this should be `isQualifierObject` by our current definitions, but that flow is not yet supported.
   }
 }