Also remove writer method for Hbc.binarydir.

Library/Homebrew/cask/lib/hbc/locations.rb

@@ -57,8 +57,6 @@ module Hbc
         @servicedir ||= Pathname.new("~/Library/Services").expand_path
       end
 
-      attr_writer :binarydir
-
       def binarydir
         @binarydir ||= HOMEBREW_PREFIX.join("bin")
       end

Library/Homebrew/test/cask/artifact/binary_spec.rb

@@ -7,10 +7,6 @@ describe Hbc::Artifact::Binary, :cask do
   let(:artifacts) { cask.artifacts.select { |a| a.is_a?(described_class) } }
   let(:expected_path) { Hbc.binarydir.join("binary") }
 
-  before(:each) do
-    Hbc.binarydir.mkpath
-  end
-
   after(:each) do
     FileUtils.rm expected_path if expected_path.exist?
   end

Library/Homebrew/test/support/helper/spec/shared_context/homebrew_cask.rb

@@ -11,14 +11,13 @@ HOMEBREW_CASK_DIRS = [
   :prefpanedir,
   :qlplugindir,
   :servicedir,
-  :binarydir,
 ].freeze
 
 RSpec.shared_context "Homebrew-Cask" do
   around(:each) do |example|
     third_party_tap = Tap.fetch("third-party", "tap")
     begin
-      [Hbc.caskroom, Hbc.cache].each(&:mkpath)
+      [Hbc.binarydir, Hbc.caskroom, Hbc.cache].each(&:mkpath)
 
       dirs = HOMEBREW_CASK_DIRS.map do |dir|
         Pathname.new(TEST_TMPDIR).join("cask-#{dir}").tap do |path|
@@ -40,7 +39,7 @@ RSpec.shared_context "Homebrew-Cask" do
       example.run
     ensure
       FileUtils.rm_rf dirs
-      FileUtils.rm_rf Hbc.caskroom, Hbc.cache
+      FileUtils.rm_rf [Hbc.binarydir, Hbc.caskroom, Hbc.cache]
       Hbc.default_tap.path.unlink
       FileUtils.rm_rf Hbc.default_tap.path.parent
       third_party_tap.path.unlink