CPP1116 — Struct inheritance mapping strange

The spec says the following:

The constructor which “accepts values for each struct member in the order they are specified in IDL” also accepts, as its first parameter, an object of the mapped base type (passed by const reference)

As user of a IDL inherited struct I would expect I can pass the members of the base type after the members of the inherited struct, not an instance of the base type. So, when there is a 2DPoint with members X and Y and a 3DPoint derived from that with member Z, I would expect to call a constructor with Z, X, Y .

Also the spec should require that a the inheriting constructor concept should be supported (see https://arne-mertz.de/2015/08/new-c-features-inherited-and-delegating-constructors/), so we can initialize a 3DPoint with only X and Y where Z receives its default value.

The remark of "passed by const reference" which is now part of the spec should be removed, that is an implementation decision, it could be that pass by value is more performant (see for example https://abseil.io/tips/117)

An example would be really helpful in this case, provide an example IDL construct with the example C++11 code expected.

Update struct inheritance mapping

The section "Structures with Single Inheritance" needs a minor update and an example