```ruby
require 'spec_helper'
require 'support/editor'

RSpec.feature "Compiling to different formats", type: :feature, js: true do
  before do
    visit '/'
    editor.set(code)
  end

  scenario "compiling to assembly" do
    within('.header') { click_on("ASM") }

    within('.output-code') do
      expect(page).to have_content '.text'
      expect(page).to have_content '.file'
      expect(page).to have_content '.section'
      expect(page).to have_content '.p2align'
    end
  end

  scenario "compiling to LLVM IR" do
    within('.header') { click_on("LLVM IR") }

    within('.output-code') do
      expect(page).to have_content 'ModuleID'
      expect(page).to have_content 'target datalayout'
      expect(page).to have_content 'target triple'
    end
  end

  def editor
    Editor.new(page)
  end

  def code
    <<~EOF
    fn main() {
        println!("Hello, world!");
    }
    EOF
  end
end
```

Add feature spec for MIR output
user
```ruby
require 'spec_helper'
require 'support/editor'
require 'support/playground_actions'

RSpec.feature "Compiling to different formats", type: :feature, js: true do
  include PlaygroundActions

  before do
    visit '/'
    editor.set(code)
  end

  scenario "compiling to assembly" do
    within('.header') { click_on("ASM") }

    within('.output-code') do
      expect(page).to have_content '.text'
      expect(page).to have_content '.file'
      expect(page).to have_content '.section'
      expect(page).to have_content '.p2align'
    end
  end

  scenario "compiling to LLVM IR" do
    within('.header') { click_on("LLVM IR") }

    within('.output-code') do
      expect(page).to have_content 'ModuleID'
      expect(page).to have_content 'target datalayout'
      expect(page).to have_content 'target triple'
    end
  end

  scenario "compiling to MIR" do
    within('.header') do
      choose_styled("Nightly")
      click_on("MIR")
    end

    within('.output-code') do
      expect(page).to have_content 'StorageLive'
      expect(page).to have_content 'StorageDead'
    end
  end

  def editor
    Editor.new(page)
  end

  def code
    <<~EOF
    fn main() {
        println!("Hello, world!");
    }
    EOF
  end
end
```
assistant