Context

I'm beginner with the library, so I'm relying a lot on the book. I read the book about the opaque rust type that I should use a Box to expose that to c++.

What I wanted to do

• I created a first function new_my_type() -> Box<MyType>.
• Then I wanted to add a fetch_some_types -> Vec<Box<MyType>> and I got unsupported element type of Vec.

How i fixed it

• of course fetch_some_types -> Vec<MyType> was enough for it to work. But I couldn't find example in the book.

What could be improved

It would be nice to have some more documentation in the book about Vec, that type should be wrapped in struct for it to work. I've found the solution with #671.

We could add in the book categories:

• Vec of opaque rust type (ie you don't need to put a Box
• Vec of an unsupported element: wrap it in a struct.