Enable and fix warnings

Library/Homebrew/extend/os/mac/dev-cmd/bottle.rb

@@ -2,8 +2,10 @@
 # frozen_string_literal: true
 
 module Homebrew
+  class << self
+    undef tar_args
     sig { returns(T::Array[String]) }
-  def self.tar_args
+    def tar_args
       if MacOS.version >= :catalina
         ["--no-mac-metadata", "--no-acls", "--no-xattrs"].freeze
       else
@@ -11,8 +13,10 @@ module Homebrew
       end
     end
 
+    undef gnu_tar
     sig { params(gnu_tar_formula: Formula).returns(String) }
-  def self.gnu_tar(gnu_tar_formula)
+    def gnu_tar(gnu_tar_formula)
       "#{gnu_tar_formula.opt_bin}/gtar"
     end
   end
+end

Library/Homebrew/livecheck/skip_conditions.rb

@@ -1,8 +1,6 @@
 # typed: true
 # frozen_string_literal: true
 
-require "livecheck/livecheck"
-
 module Homebrew
   module Livecheck
     # The `Livecheck::SkipConditions` module primarily contains methods that

Library/Homebrew/test/livecheck/skip_conditions_spec.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require "livecheck/livecheck"
 require "livecheck/skip_conditions"
 
 describe Homebrew::Livecheck::SkipConditions do

Library/Homebrew/test/spec_helper.rb

@@ -66,6 +66,7 @@ RSpec.configure do |config|
   config.order = :random
 
   config.raise_errors_for_deprecations!
+  config.warnings = true
 
   config.filter_run_when_matching :focus
 
@@ -179,6 +180,7 @@ RSpec.configure do |config|
   end
 
   config.around do |example|
+    undef find_files if defined? find_files
     def find_files
       return [] unless File.exist?(TEST_TMPDIR)