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#### 8.2.2 Incorrect Remote Dispatching

When a remote subprogram takes a class wide argument, there is a risk of using an object of a derived type that will not be clean enough to be transmitted. For example, given a type called Root_Type, if a remote procedure takes a Root_Type'Class as an argument, the user can call it with an instance of Derived_Type that is Root_Type enriched with a field of a task type. This will lead to a non-communicable type to be transmitted between partitions.

To prevent this, paragraph E.4(18) of the Ada Reference Manual explains that any actual type used as parameter for a remote call whose formal type is a class wide type must be declared in the visible part of a Pure or Remote_Types package. This property also holds for remote functions returning class wide types. To summarize, the actual type used should have been eligible for being declared where the root type has been declared. If a `bad' object is given to a remote subprogram, Program_Error will be raised at the point of the call.