Once SERVER-96197, ExpressionContext's resolvedNamespaces map will be keyed on NamespaceString's instead of collection names. This means that for the collection nss key case, we will have keys that map to a copy of the key. We could instead have collection nss keys map to empty entries , while still having entries that contain the underlying collection nss, pipeline, and other flags for view nss keys. We have to be careful not to logically conflict with the ongoing changes to the ResolvedNamespace struct or remove any information that we used to have.