diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 3679d4af40..ba6592eba5 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -127,6 +127,17 @@ then
   HOMEBREW_CACHE="${HOMEBREW_CACHE:-${HOME}/Library/Caches/Homebrew}"
   HOMEBREW_LOGS="${HOMEBREW_LOGS:-${HOME}/Library/Logs/Homebrew}"
   HOMEBREW_SYSTEM_TEMP="/private/tmp"
+
+  # Set a variable when the macOS system Ruby is new enough to avoid spawning
+  # a Ruby process unnecessarily.
+  if [[ "$HOMEBREW_MACOS_VERSION_NUMERIC" -lt "101303" ]]
+  then
+    unset HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH
+  else
+    # Used in ruby.sh.
+    # shellcheck disable=SC2034
+    HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH="1"
+  fi
 else
   HOMEBREW_PROCESSOR="$(uname -m)"
   HOMEBREW_PRODUCT="${HOMEBREW_SYSTEM}brew"
@@ -157,6 +168,8 @@ else
   HOMEBREW_CACHE="${HOMEBREW_CACHE:-${CACHE_HOME}/Homebrew}"
   HOMEBREW_LOGS="${HOMEBREW_LOGS:-${CACHE_HOME}/Homebrew/Logs}"
   HOMEBREW_SYSTEM_TEMP="/tmp"
+
+  unset HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH
 fi
 
 if [[ -n "$HOMEBREW_MACOS" || -n "$HOMEBREW_FORCE_HOMEBREW_ON_LINUX" ]]
@@ -327,6 +340,12 @@ then
 
   # Don't allow non-developers to customise Ruby warnings.
   unset HOMEBREW_RUBY_WARNINGS
+
+  # Disable Ruby options we don't need. RubyGems provides a decent speedup.
+  RUBY_DISABLE_OPTIONS="--disable=gems,did_you_mean,rubyopt"
+else
+  # Don't disable did_you_mean for developers as it's useful.
+  RUBY_DISABLE_OPTIONS="--disable=gems,rubyopt"
 fi
 
 if [[ -z "$HOMEBREW_RUBY_WARNINGS" ]]
@@ -480,5 +499,5 @@ else
 
   # Unshift command back into argument list (unless argument list was empty).
   [[ "$HOMEBREW_ARG_COUNT" -gt 0 ]] && set -- "$HOMEBREW_COMMAND" "$@"
-  { update-preinstall "$@"; exec "$HOMEBREW_RUBY_PATH" $HOMEBREW_RUBY_WARNINGS "$HOMEBREW_LIBRARY/Homebrew/brew.rb" "$@"; }
+  { update-preinstall "$@"; exec "$HOMEBREW_RUBY_PATH" $HOMEBREW_RUBY_WARNINGS "$RUBY_DISABLE_OPTIONS" "$HOMEBREW_LIBRARY/Homebrew/brew.rb" "$@"; }
 fi
diff --git a/Library/Homebrew/formula_assertions.rb b/Library/Homebrew/formula_assertions.rb
index f81087a3dd..2ef69d6d7c 100644
--- a/Library/Homebrew/formula_assertions.rb
+++ b/Library/Homebrew/formula_assertions.rb
@@ -1,5 +1,6 @@
 module Homebrew
   module Assertions
+    require "rubygems"
     require "test/unit/assertions"
     include ::Test::Unit::Assertions
 
diff --git a/Library/Homebrew/shims/super/cc b/Library/Homebrew/shims/super/cc
index 2c90e5e939..9957789aba 100755
--- a/Library/Homebrew/shims/super/cc
+++ b/Library/Homebrew/shims/super/cc
@@ -1,13 +1,11 @@
 #!/bin/sh
 # Make sure this shim uses the same Ruby interpreter that is used by Homebrew.
-unset RUBYLIB
-unset RUBYOPT
 if [ -z "$HOMEBREW_RUBY_PATH" ]
 then
   echo "${0##*/}: The build tool has reset ENV; --env=std required." >&2
   exit 1
 fi
-exec "$HOMEBREW_RUBY_PATH" -x "$0" "$@"
+exec "$HOMEBREW_RUBY_PATH" --disable=gems,did_you_mean,rubyopt -x "$0" "$@"
 #!/usr/bin/env ruby -W0
 
 require "pathname"
diff --git a/Library/Homebrew/style.rb b/Library/Homebrew/style.rb
index f2ce76b0ee..f4d53e5a1b 100644
--- a/Library/Homebrew/style.rb
+++ b/Library/Homebrew/style.rb
@@ -100,7 +100,7 @@ module Homebrew
         raise "Invalid output_type for check_style_impl: #{output_type}"
       end
 
-      return !rubocop_success if !files.nil? && !has_non_formula
+      return !rubocop_success if files.present? || !has_non_formula
 
       shellcheck   = which("shellcheck")
       shellcheck ||= which("shellcheck", ENV["HOMEBREW_PATH"])
diff --git a/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb b/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
index 902204e1d8..f79df38dd4 100644
--- a/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
+++ b/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
@@ -89,6 +89,7 @@ RSpec.shared_context "integration test" do
         "-I", $LOAD_PATH.join(File::PATH_SEPARATOR)
       ]
       if ENV["HOMEBREW_TESTS_COVERAGE"]
+        require "rubygems"
         simplecov_spec = Gem.loaded_specs["simplecov"]
         specs = [simplecov_spec]
         simplecov_spec.runtime_dependencies.each do |dep|
diff --git a/Library/Homebrew/utils/gems.rb b/Library/Homebrew/utils/gems.rb
index 5b16b0bee2..04beb2c8cb 100644
--- a/Library/Homebrew/utils/gems.rb
+++ b/Library/Homebrew/utils/gems.rb
@@ -12,6 +12,7 @@ module Homebrew
   end
 
   def gem_user_bindir
+    require "rubygems"
     "#{Gem.user_dir}/bin".freeze
   end
 
@@ -39,6 +40,7 @@ module Homebrew
     ENV["GEM_PATH"] = ENV["GEM_HOME"]
 
     # Make RubyGems notice environment changes.
+    require "rubygems"
     Gem.clear_paths
     Gem::Specification.reset
 
@@ -76,6 +78,7 @@ module Homebrew
   end
 
   def install_bundler!
+    require "rubygems"
     setup_gem_environment!(gem_home: Gem.user_dir, gem_bindir: gem_user_bindir)
     install_gem_setup_path!("bundler", version: ">=2", executable: "bundle", setup_gem_environment: false)
   end
diff --git a/Library/Homebrew/utils/ruby.sh b/Library/Homebrew/utils/ruby.sh
index 91b30efe15..b1a2988505 100644
--- a/Library/Homebrew/utils/ruby.sh
+++ b/Library/Homebrew/utils/ruby.sh
@@ -35,9 +35,12 @@ setup-ruby-path() {
         HOMEBREW_RUBY_PATH="$(type -P ruby)"
       fi
 
-      if [[ -n "$HOMEBREW_RUBY_PATH" && -z "$HOMEBREW_FORCE_VENDOR_RUBY" ]]
+      if [[ -n "$HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH" ]]
       then
-        ruby_version_new_enough="$("$HOMEBREW_RUBY_PATH" -rrubygems -e "puts Gem::Version.new(RUBY_VERSION.to_s.dup) >= Gem::Version.new('$minimum_ruby_version')")"
+        ruby_version_new_enough="true"
+      elif [[ -n "$HOMEBREW_RUBY_PATH" && -z "$HOMEBREW_FORCE_VENDOR_RUBY" ]]
+      then
+        ruby_version_new_enough="$("$HOMEBREW_RUBY_PATH" --disable=gems -rrubygems -e "puts Gem::Version.new(RUBY_VERSION.to_s.dup) >= Gem::Version.new('$minimum_ruby_version')")"
       fi
 
       if [[ -z "$HOMEBREW_RUBY_PATH" || -n "$HOMEBREW_FORCE_VENDOR_RUBY" || "$ruby_version_new_enough" != "true" ]]