diff --git a/Library/Homebrew/cli_parser.rb b/Library/Homebrew/cli_parser.rb
index f35328a574..d8440aed6e 100644
--- a/Library/Homebrew/cli_parser.rb
+++ b/Library/Homebrew/cli_parser.rb
@@ -135,6 +135,7 @@ module Homebrew
         check_constraint_violations
         Homebrew.args[:remaining] = remaining_args
         Homebrew.args.freeze
+        cmdline_args.freeze
         @parser
       end
 
diff --git a/Library/Homebrew/dev-cmd/irb.rb b/Library/Homebrew/dev-cmd/irb.rb
index 4e57bffd91..358feda611 100644
--- a/Library/Homebrew/dev-cmd/irb.rb
+++ b/Library/Homebrew/dev-cmd/irb.rb
@@ -31,7 +31,8 @@ module Homebrew
   end
 
   def irb
-    irb_args.parse
+    # work around IRB modifying ARGV.
+    irb_args.parse(ARGV.dup)
 
     if args.examples?
       puts "'v8'.f # => instance of the v8 formula"
diff --git a/Library/Homebrew/extend/ARGV.rb b/Library/Homebrew/extend/ARGV.rb
index ac931df1f5..857a856903 100644
--- a/Library/Homebrew/extend/ARGV.rb
+++ b/Library/Homebrew/extend/ARGV.rb
@@ -30,7 +30,8 @@ module HomebrewArgvExtension
   end
 
   def named
-    @named ||= self - options_only
+    # TODO: use @instance variable to ||= cache when moving to CLI::Parser
+    self - options_only
   end
 
   def options_only
@@ -43,7 +44,8 @@ module HomebrewArgvExtension
 
   def formulae
     require "formula"
-    @formulae ||= (downcased_unique_named - casks).map do |name|
+    # TODO: use @instance variable to ||= cache when moving to CLI::Parser
+    (downcased_unique_named - casks).map do |name|
       if name.include?("/") || File.exist?(name)
         Formulary.factory(name, spec)
       else
@@ -54,19 +56,22 @@ module HomebrewArgvExtension
 
   def resolved_formulae
     require "formula"
-    @resolved_formulae ||= (downcased_unique_named - casks).map do |name|
+    # TODO: use @instance variable to ||= cache when moving to CLI::Parser
+    (downcased_unique_named - casks).map do |name|
       Formulary.resolve(name, spec: spec(nil))
     end.uniq(&:name)
   end
 
   def casks
-    @casks ||= downcased_unique_named.grep HOMEBREW_CASK_TAP_CASK_REGEX
+    # TODO: use @instance variable to ||= cache when moving to CLI::Parser
+    downcased_unique_named.grep HOMEBREW_CASK_TAP_CASK_REGEX
   end
 
   def kegs
     require "keg"
     require "formula"
-    @kegs ||= downcased_unique_named.map do |name|
+    # TODO: use @instance variable to ||= cache when moving to CLI::Parser
+    downcased_unique_named.map do |name|
       raise UsageError if name.empty?
 
       rack = Formulary.to_rack(name.downcase)
@@ -109,7 +114,7 @@ module HomebrewArgvExtension
   end
 
   def include?(arg)
-    !(@n = index(arg)).nil?
+    !index(arg).nil?
   end
 
   def next
@@ -281,7 +286,8 @@ module HomebrewArgvExtension
 
   def downcased_unique_named
     # Only lowercase names, not paths, bottle filenames or URLs
-    @downcased_unique_named ||= named.map do |arg|
+    # TODO: use @instance variable to ||= cache when moving to CLI::Parser
+    named.map do |arg|
       if arg.include?("/") || arg.end_with?(".tar.gz") || File.exist?(arg)
         arg
       else