Interpreter: cast proc call arguments to proc arg types

[asterite]

Fixes #12350

Note that for the example in #12350 to work it also needs #12374 merged.

[asterite]

It seems Fiber#@proc is of type Proc(Nil) | Proc(Void) 😅 . I think those two types should be unified.

I'll try to fix it here too... that shouldn't happen.

[asterite]

Actually, I'll just fix the interpreter for now.

[asterite]

I can confirm #12388 makes this work without the workaround, so we might want to merge that one first.

[asterite]

I just undid the workaround. Let's see if CI passes now :-)

[asterite]

CI failed and I have a fix for this. But I found out that a lot more primitive calls are broken if they happen inside a closure, so I'm going to do a general fix for that.

[asterite]

So, the last non-merge commit is doing this. If you had code like this:

struct Enum
  def foo
    ->{
      value
    }
  end
end

enum Color
  Red
  Green
end

p Color::Green.foo.call

the "scope" (the type of self) inside the proc literal was incorrectly Program instead of Enum (or Color) in this case. This affected all primitive calls that happened without a receiver in a proc literal, so it was affecting Proc#call and probably many others. The last commit preserves the correct scope inside proc literals.