diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 38aec67befa..f2d3418b64a 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -69,15 +69,6 @@ Style/MapToHash:
   Exclude:
     - 'app/models/status.rb'
 
-# This cop supports unsafe autocorrection (--autocorrect-all).
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: literals, strict
-Style/MutableConstant:
-  Exclude:
-    - 'app/models/tag.rb'
-    - 'app/services/delete_account_service.rb'
-    - 'lib/mastodon/migration_warning.rb'
-
 # Configuration parameters: AllowedMethods.
 # AllowedMethods: respond_to_missing?
 Style/OptionalBooleanParameter:
diff --git a/app/models/tag.rb b/app/models/tag.rb
index c9115b905b3..d29cd220f03 100644
--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@@ -35,11 +35,11 @@ class Tag < ApplicationRecord
   has_one :trend, class_name: 'TagTrend', inverse_of: :tag, dependent: :destroy
 
   HASHTAG_SEPARATORS = "_\u00B7\u30FB\u200c"
-  HASHTAG_FIRST_SEQUENCE_CHUNK_ONE = "[[:word:]_][[:word:]#{HASHTAG_SEPARATORS}]*[[:alpha:]#{HASHTAG_SEPARATORS}]"
-  HASHTAG_FIRST_SEQUENCE_CHUNK_TWO = "[[:word:]#{HASHTAG_SEPARATORS}]*[[:word:]_]"
-  HASHTAG_FIRST_SEQUENCE = "(#{HASHTAG_FIRST_SEQUENCE_CHUNK_ONE}#{HASHTAG_FIRST_SEQUENCE_CHUNK_TWO})"
+  HASHTAG_FIRST_SEQUENCE_CHUNK_ONE = "[[:word:]_][[:word:]#{HASHTAG_SEPARATORS}]*[[:alpha:]#{HASHTAG_SEPARATORS}]".freeze
+  HASHTAG_FIRST_SEQUENCE_CHUNK_TWO = "[[:word:]#{HASHTAG_SEPARATORS}]*[[:word:]_]".freeze
+  HASHTAG_FIRST_SEQUENCE = "(#{HASHTAG_FIRST_SEQUENCE_CHUNK_ONE}#{HASHTAG_FIRST_SEQUENCE_CHUNK_TWO})".freeze
   HASHTAG_LAST_SEQUENCE = '([[:word:]_]*[[:alpha:]][[:word:]_]*)'
-  HASHTAG_NAME_PAT = "#{HASHTAG_FIRST_SEQUENCE}|#{HASHTAG_LAST_SEQUENCE}"
+  HASHTAG_NAME_PAT = "#{HASHTAG_FIRST_SEQUENCE}|#{HASHTAG_LAST_SEQUENCE}".freeze
 
   HASHTAG_RE = %r{(?<![=/)\p{Alnum}])#(#{HASHTAG_NAME_PAT})}
   HASHTAG_NAME_RE = /\A(#{HASHTAG_NAME_PAT})\z/i
diff --git a/app/services/delete_account_service.rb b/app/services/delete_account_service.rb
index 7d06302af5a..20d6ee8d64e 100644
--- a/app/services/delete_account_service.rb
+++ b/app/services/delete_account_service.rb
@@ -51,7 +51,7 @@ class DeleteAccountService < BaseService
     scheduled_statuses
     status_pins
     tag_follows
-  )
+  ).freeze
 
   ASSOCIATIONS_ON_DESTROY = %w(
     reports
diff --git a/lib/mastodon/migration_warning.rb b/lib/mastodon/migration_warning.rb
index 227f6705d3f..b90ceb29165 100644
--- a/lib/mastodon/migration_warning.rb
+++ b/lib/mastodon/migration_warning.rb
@@ -4,7 +4,7 @@ module Mastodon
   module MigrationWarning
     WARNING_SECONDS = 10
 
-    DEFAULT_WARNING = <<~WARNING_MESSAGE
+    DEFAULT_WARNING = <<~WARNING_MESSAGE.freeze
       WARNING: This migration may take a *long* time for large instances.
       It will *not* lock tables for any significant time, but it may run
       for a very long time. We will pause for #{WARNING_SECONDS} seconds to allow you to