Extending a parameter that extends another parameter doesn't work as expected

[garrettrathbone]

Description
If a model/parameter (model 1) extends another model/parameter (model 2) that itself extends another model/parameter (model 3), it should be assumed that model 1 has properties that were pulled through from model 3, but instead only values from model 2 are pulled through.

How to reproduce
Create 3 models:

• model 3 have a property on it
• model 2 extends model 3 with a different property
• model 1 extends model 2

You'd expect model 1 to then have properties from both model 2 and 3, but it only has properties from model 2.

Possible Solution
I believe the issue is being caused from when the extends is converted to an array to add to the data on parameter construction in the Parameter class.
$data += $extends->toArray(); The toArray method returns the originalData property, which is never modified even when extending.

The possible solution would be to additionally merge the $extends->toArray() data in with the $this->originalData at the same time as when it's added to the current $data. Either that or set $data to $this->originalData (which currently happens first) after the $ref and extends functionality is ran.