When parent scopes around an eval are forwarding parameters (like
*, **, &, or ...) we need to know that information when we are in
the parser. As such, we need to support passing that information
into the scopes option. In order to do this, unfortunately we need
a bunch of changes.
The scopes option was previously an array of array of strings.
These corresponded to the names of the locals in the parent scopes.
We still support this, but now additionally support passing in a
Prism::Scope instance at each index in the array. This Prism::Scope
class holds both the names of the locals as well as an array of
forwarding parameter names (symbols corresponding to the forwarding
parameters). There is convenience function on the Prism module that
creates a Prism::Scope object using Prism.scope.
In JavaScript, we now additionally support an object much the same
as the Ruby side. In Java, we now have a ParsingOptions.Scope class
that holds that information. In the dump APIs, these objects in all
3 languages will add an additional byte for the forwarding flags in
the middle of the scopes serialization.
All of this is in service of properly parsing the following code:
```ruby
def foo(*) = eval("bar(*)")
```
https://github.com/ruby/prism/commit/21abb6b7c4