Impossible to specify annotations for implicit ports

[fschopp]

Currently (from RuntimeAnnotatedExecutionTrace#getAnnotation(RuntimeName)):

An annotation A is present on an execution trace E that does not represent an annotated element if A is present on the nearest enclosing execution trace representing an annotated element. For instance, the annotations present on execution trace /module:in:array:1:2 are those present on /module:in:array. If no nearest enclosing element exists, an IllegalStateException exception will be thrown.

However, a module's annotations are never present on any of its ports (both modules and ports are language elements, so the above provision does not apply).

This means that it is impossible to specify annotations for implicit ports, except via overrides. This is potentially a problem because it means that one cannot specify, e.g., what serialization plug-in to use to serialize the value of an input module.