expr = (ScalarExpression)expressionsByVariableName.get(name);
if (expr == null)
{
// Type will be null here since we have no types specified for implicit variables
// The type will be set later when we know its context
expr = new UnboundVariable(qs, name,
(Class)variableTypesByName.get(name), this);
variableNames.add(name);
// We should really add this to variableTypesByName but we don't know the type here
fieldExpressions.add(expr); // Add to the field expressions list
}