Tapioca automatically converts nested style to compact style, causing 'Unable to resolve constant $class' error in RBI

sorbet version: 0.5.11332
tapioca version: 0.13.1
ruby version: 3.2.2

I encountered an issue when using Tapioca to generate RBI files for a gem dependency. The generated RBI file contains an Unable to resolve constant $class error.

Here's a minimal reproduction of the issue:

In repo X, I have the following files:
lib/x.rb

module X
  class Foo
  end

  class Bar
    def foo
      Foo.new
    end
  end
end

rbi/defs.rbi

# typed: strong

module X
  class Foo
  end

  class Bar
    sig { returns(Foo) }
    def foo
    end
  end
end

In repo Y, which depends on the gem from repo X, I have the following files:
Gemfile

gem "x"

After running bin/tapioca gem, the generated RBI file at sorbet/rbi/gems/x.rbi looks like this:

module X; end

class X::Foo
end

class X::Bar
  sig { returns(Foo) } # Unable to resolve constant `Foo`
  def foo
  end
end

Suspect file: pipeline.rb on GitHub

Start with the minimal reproduction in the issue and run bin/tapioca gem to observe the generated sorbet/rbi/gems/x.rbi. Read lib/tapioca/gem/pipeline.rb, the suspected entry point, and trace how nested declarations become compact style. Done means the generated RBI no longer reports an unresolved Foo constant for X::Bar#foo.