diff --git a/.rubocop.yml b/.rubocop.yml
index 5f1d0dc80..f7f418ced 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -72,3 +72,5 @@ Style/FileName:
         - 'lib/puppet-lint.rb'
         - 'lib/puppet-lint/tasks/puppet-lint.rb'
         - 'spec/puppet-lint_spec.rb'
+Style/FrozenStringLiteralComment:
+  Enabled: false
diff --git a/Rakefile b/Rakefile
index c156c2bf9..a62bdfde2 100644
--- a/Rakefile
+++ b/Rakefile
@@ -41,6 +41,6 @@ rescue LoadError
   $stderr.puts 'Rubocop is not available for this version of Ruby.'
 end
 
-task :ci => [:test, :release_test]
+task :ci => %i[test release_test]
 
 # vim: syntax=ruby
diff --git a/lib/puppet-lint/checkplugin.rb b/lib/puppet-lint/checkplugin.rb
index a1fa65730..0497e512c 100644
--- a/lib/puppet-lint/checkplugin.rb
+++ b/lib/puppet-lint/checkplugin.rb
@@ -168,11 +168,11 @@ def notify(kind, problem)
     problem[:kind] = kind
     problem.merge!(default_info) { |_key, v1, _v2| v1 }
 
-    unless [:warning, :error, :fixed].include?(kind)
+    unless %i[warning error fixed].include?(kind)
       raise ArgumentError, 'unknown value passed for kind'
     end
 
-    [:message, :line, :column, :check].each do |attr|
+    %i[message line column check].each do |attr|
       unless problem.key?(attr)
         raise ArgumentError, "problem hash must contain #{attr.inspect}"
       end
diff --git a/lib/puppet-lint/data.rb b/lib/puppet-lint/data.rb
index 652408980..e122b1b30 100644
--- a/lib/puppet-lint/data.rb
+++ b/lib/puppet-lint/data.rb
@@ -68,10 +68,10 @@ def insert(index, token)
       token.next_token = current_token.next_token
       token.prev_token = current_token
 
-      current_token.next_token.prev_token = token unless current_token.next_token.nil?
+      current_token.next_token&.prev_token = token
 
       unless formatting_tokens.include?(token.type)
-        current_token.next_token.prev_code_token = token unless current_token.next_token.nil?
+        current_token.next_token&.prev_code_token = token
         next_nf_idx = tokens[index..-1].index { |r| !formatting_tokens.include?(r.type) }
         unless next_nf_idx.nil?
           next_nf_token = tokens[index + next_nf_idx]
@@ -101,11 +101,11 @@ def insert(index, token)
 
     # Public: Removes a token
     def delete(token)
-      token.next_token.prev_token = token.prev_token unless token.next_token.nil?
-      token.prev_token.next_token = token.next_token unless token.prev_token.nil?
+      token.next_token&.prev_token = token.prev_token
+      token.prev_token&.next_token = token.next_token
       unless formatting_tokens.include?(token.type)
-        token.prev_code_token.next_code_token = token.next_code_token unless token.prev_code_token.nil?
-        token.next_code_token.prev_code_token = token.prev_code_token unless token.next_code_token.nil?
+        token.prev_code_token&.next_code_token = token.next_code_token
+        token.next_code_token&.prev_code_token = token.prev_code_token
       end
 
       tokens.delete(token)
@@ -174,7 +174,7 @@ def resource_indexes
           rel_start_idx = tokens[marker..-1].index(colon_token)
           break if rel_start_idx.nil?
           start_idx = rel_start_idx + marker
-          end_token = colon_token.next_token_of([:SEMIC, :RBRACE])
+          end_token = colon_token.next_token_of(%i[SEMIC RBRACE])
           rel_end_idx = tokens[start_idx..-1].index(end_token)
           raise PuppetLint::SyntaxError, colon_token if rel_end_idx.nil?
           marker = rel_end_idx + start_idx
@@ -344,7 +344,7 @@ def function_indexes
           next unless token.type == :NAME
           next unless token_idx.zero? ||
                       (token_idx == 1 && tokens[0].type == :WHITESPACE) ||
-                      [:NEWLINE, :INDENT].include?(token.prev_token.type) ||
+                      %i[NEWLINE INDENT].include?(token.prev_token.type) ||
                       # function in a function
                       (token.prev_code_token && token.prev_code_token.type == :LPAREN)
 
@@ -428,7 +428,7 @@ def hash_indexes
         tokens.each_with_index do |token, token_idx|
           next unless token.type == :LBRACE
           next unless token.prev_code_token
-          next unless [:EQUALS, :ISEQUAL, :FARROW, :LPAREN].include?(token.prev_code_token.type)
+          next unless %i[EQUALS ISEQUAL FARROW LPAREN].include?(token.prev_code_token.type)
 
           level = 0
           real_idx = 0
@@ -437,7 +437,7 @@ def hash_indexes
 
             level += 1 if cur_token.type == :LBRACE
             level -= 1 if cur_token.type == :RBRACE
-            break if level < 0
+            break if level.negative?
           end
 
           hashes << {
@@ -561,7 +561,7 @@ def parse_control_comments
 
         comment_words = token.value.strip.split(%r{\s+})
         comment_words.each_with_index do |word, i|
-          if word =~ %r{\Alint\:(ignore|endignore)}
+          if word.match?(%r{\Alint\:(ignore|endignore)})
             comment_data << word
           else
             # Once we reach the first non-controlcomment word, assume the rest
diff --git a/lib/puppet-lint/lexer.rb b/lib/puppet-lint/lexer.rb
index e9d1696b3..9499fea8a 100644
--- a/lib/puppet-lint/lexer.rb
+++ b/lib/puppet-lint/lexer.rb
@@ -232,7 +232,7 @@ def tokenise(code)
                  end
           tokens << new_token(:VARIABLE, var_name, opts)
 
-        elsif chunk =~ %r{\A'.*?'}m
+        elsif chunk.match?(%r{\A'.*?'}m)
           str_content = StringScanner.new(code[i + 1..-1]).scan_until(%r{(\A|[^\\])(\\\\)*'}m)
           length = str_content.size + 1
           tokens << new_token(:SSTRING, str_content[0..-2])
diff --git a/lib/puppet-lint/lexer/token.rb b/lib/puppet-lint/lexer/token.rb
index 5384932a4..df2fc6882 100644
--- a/lib/puppet-lint/lexer/token.rb
+++ b/lib/puppet-lint/lexer/token.rb
@@ -111,7 +111,7 @@ def to_manifest
       end
 
       def string_suffix
-        no_enclose_tokens = Set.new([:UNENC_VARIABLE, :DQMID, :DQPOST, :HEREDOC_MID, :HEREDOC_POST])
+        no_enclose_tokens = Set.new(%i[UNENC_VARIABLE DQMID DQPOST HEREDOC_MID HEREDOC_POST])
         if next_token && no_enclose_tokens.include?(next_token.type)
           ''
         else
@@ -120,7 +120,7 @@ def string_suffix
       end
 
       def string_prefix
-        no_enclose_tokens = Set.new([:UNENC_VARIABLE, :DQPRE, :DQMID, :HEREDOC_PRE, :HEREDOC_MID])
+        no_enclose_tokens = Set.new(%i[UNENC_VARIABLE DQPRE DQMID HEREDOC_PRE HEREDOC_MID])
         if prev_token && no_enclose_tokens.include?(prev_token.type)
           ''
         else
@@ -169,7 +169,7 @@ def prev_token_of(type, opts = {})
       # Returns a PuppetLint::Lexer::Token object if a matching token could be
       # found, otherwise nil.
       def find_token_of(direction, type, opts = {})
-        return nil unless [:next, :prev].include?(direction)
+        return nil unless %i[next prev].include?(direction)
 
         opts[:skip_blocks] ||= true
         to_find = Array[*type]
diff --git a/lib/puppet-lint/optparser.rb b/lib/puppet-lint/optparser.rb
index bb1e1ef1b..dc3195fe6 100644
--- a/lib/puppet-lint/optparser.rb
+++ b/lib/puppet-lint/optparser.rb
@@ -47,7 +47,7 @@ def self.build(args = [])
 
       opts.on(
         '--error-level LEVEL',
-        [:all, :warning, :error],
+        %i[all warning error],
         'The level of error to return (warning, error or all).'
       ) do |el|
         PuppetLint.configuration.error_level = el
diff --git a/lib/puppet-lint/plugins/check_classes/arrow_on_right_operand_line.rb b/lib/puppet-lint/plugins/check_classes/arrow_on_right_operand_line.rb
index d2646f45f..ce23a44de 100644
--- a/lib/puppet-lint/plugins/check_classes/arrow_on_right_operand_line.rb
+++ b/lib/puppet-lint/plugins/check_classes/arrow_on_right_operand_line.rb
@@ -34,6 +34,6 @@ def fix(problem)
     # Remove trailing whitespace after left operand (if it exists)
     return unless left_operand_token.next_token.type == :WHITESPACE
     trailing_whitespace_token = left_operand_token.next_token
-    remove_token(trailing_whitespace_token) if [:NEWLINE, :WHITESPACE].include?(trailing_whitespace_token.next_token.type)
+    remove_token(trailing_whitespace_token) if %i[NEWLINE WHITESPACE].include?(trailing_whitespace_token.next_token.type)
   end
 end
diff --git a/lib/puppet-lint/plugins/check_classes/names_containing_uppercase.rb b/lib/puppet-lint/plugins/check_classes/names_containing_uppercase.rb
index c4e53d81a..03a22fb0f 100644
--- a/lib/puppet-lint/plugins/check_classes/names_containing_uppercase.rb
+++ b/lib/puppet-lint/plugins/check_classes/names_containing_uppercase.rb
@@ -5,7 +5,7 @@
 PuppetLint.new_check(:names_containing_uppercase) do
   def check
     (class_indexes + defined_type_indexes).each do |class_idx|
-      next unless class_idx[:name_token].value =~ %r{[A-Z]}
+      next unless class_idx[:name_token].value.match?(%r{[A-Z]})
 
       obj_type = if class_idx[:type] == :CLASS
                    'class'
diff --git a/lib/puppet-lint/plugins/check_classes/parameter_order.rb b/lib/puppet-lint/plugins/check_classes/parameter_order.rb
index ddadd80e0..48f1a09ad 100644
--- a/lib/puppet-lint/plugins/check_classes/parameter_order.rb
+++ b/lib/puppet-lint/plugins/check_classes/parameter_order.rb
@@ -55,7 +55,7 @@ def required_parameter?(token)
     data_type = token.prev_token_of(:TYPE, :skip_blocks => true)
     return false if data_type && data_type.value == 'Optional'
 
-    if token.next_code_token.nil? || [:COMMA, :RPAREN].include?(token.next_code_token.type)
+    if token.next_code_token.nil? || %i[COMMA RPAREN].include?(token.next_code_token.type)
       return !(token.prev_code_token && token.prev_code_token.type == :EQUALS)
     end
 
diff --git a/lib/puppet-lint/plugins/check_classes/variable_scope.rb b/lib/puppet-lint/plugins/check_classes/variable_scope.rb
index d6960b542..76538a088 100644
--- a/lib/puppet-lint/plugins/check_classes/variable_scope.rb
+++ b/lib/puppet-lint/plugins/check_classes/variable_scope.rb
@@ -41,13 +41,11 @@ def check
       referenced_variables = Set[]
       object_tokens = idx[:tokens]
 
-      unless idx[:param_tokens].nil?
-        idx[:param_tokens].each do |token|
-          next unless token.type == :VARIABLE
-          next unless POST_VAR_TOKENS.include?(token.next_code_token.type)
+      idx[:param_tokens]&.each do |token|
+        next unless token.type == :VARIABLE
+        next unless POST_VAR_TOKENS.include?(token.next_code_token.type)
 
-          variables_in_scope << token.value
-        end
+        variables_in_scope << token.value
       end
 
       future_parser_scopes = {}
@@ -124,9 +122,9 @@ def check
         end
 
         next if token.value.include?('::')
-        next if token.value =~ %r{^(facts|trusted)\[.+\]}
+        next if token.value.match?(%r{^(facts|trusted)\[.+\]})
         next if variables_in_scope.include?(token.value.gsub(%r{\[.+\]\Z}, ''))
-        next if token.value =~ %r{\A\d+\Z}
+        next if token.value.match?(%r{\A\d+\Z})
 
         notify(
           :warning,
diff --git a/lib/puppet-lint/plugins/check_resources/ensure_first_param.rb b/lib/puppet-lint/plugins/check_resources/ensure_first_param.rb
index 019913b39..a0456736d 100644
--- a/lib/puppet-lint/plugins/check_resources/ensure_first_param.rb
+++ b/lib/puppet-lint/plugins/check_resources/ensure_first_param.rb
@@ -32,7 +32,7 @@ def fix(problem)
 
     raise PuppetLint::NoFix if ensure_param_name_token.nil?
 
-    ensure_param_comma_token = ensure_param_name_token.next_token_of([:COMMA, :SEMIC])
+    ensure_param_comma_token = ensure_param_name_token.next_token_of(%i[COMMA SEMIC])
 
     if first_param_name_token.nil? || first_param_comma_token.nil? || ensure_param_comma_token.nil?
       raise PuppetLint::NoFix
diff --git a/lib/puppet-lint/plugins/check_resources/file_mode.rb b/lib/puppet-lint/plugins/check_resources/file_mode.rb
index 20417cb9b..34177bc61 100644
--- a/lib/puppet-lint/plugins/check_resources/file_mode.rb
+++ b/lib/puppet-lint/plugins/check_resources/file_mode.rb
@@ -19,7 +19,7 @@ def check
         value_token = param_token.next_code_token.next_code_token
 
         break if IGNORE_TYPES.include?(value_token.type)
-        break if value_token.value =~ MODE_RE
+        break if value_token.value.match?(MODE_RE)
 
         notify(
           :warning,
@@ -33,7 +33,7 @@ def check
   end
 
   def fix(problem)
-    raise PuppetLint::NoFix unless problem[:token].value =~ %r{\A[0-7]{3}\Z}
+    raise PuppetLint::NoFix unless problem[:token].value.match?(%r{\A[0-7]{3}\Z})
 
     problem[:token].type = :SSTRING
     problem[:token].value = "0#{problem[:token].value}"
diff --git a/lib/puppet-lint/plugins/check_strings/puppet_url_without_modules.rb b/lib/puppet-lint/plugins/check_strings/puppet_url_without_modules.rb
index 7783682f9..1ca92f396 100644
--- a/lib/puppet-lint/plugins/check_strings/puppet_url_without_modules.rb
+++ b/lib/puppet-lint/plugins/check_strings/puppet_url_without_modules.rb
@@ -8,7 +8,7 @@ def check
     tokens.select { |token|
       (token.type == :SSTRING || token.type == :STRING || token.type == :DQPRE) && token.value.start_with?('puppet://')
     }.reject { |token|
-      token.value[%r{puppet://.*?/(.+)}, 1].start_with?('modules/') unless token.value[%r{puppet://.*?/(.+)}, 1].nil?
+      token.value[%r{puppet://.*?/(.+)}, 1]&.start_with?('modules/')
     }.each do |token|
       notify(
         :warning,
diff --git a/lib/puppet-lint/plugins/check_variables/variable_contains_dash.rb b/lib/puppet-lint/plugins/check_variables/variable_contains_dash.rb
index 5e65e6e4a..7a71935b5 100644
--- a/lib/puppet-lint/plugins/check_variables/variable_contains_dash.rb
+++ b/lib/puppet-lint/plugins/check_variables/variable_contains_dash.rb
@@ -9,7 +9,7 @@ def check
     tokens.select { |r|
       VARIABLE_DASH_TYPES.include?(r.type)
     }.each do |token|
-      next unless token.value.gsub(%r{\[.+?\]}, '') =~ %r{-}
+      next unless token.value.gsub(%r{\[.+?\]}, '').match?(%r{-})
 
       notify(
         :warning,
diff --git a/lib/puppet-lint/plugins/check_variables/variable_is_lowercase.rb b/lib/puppet-lint/plugins/check_variables/variable_is_lowercase.rb
index 6d90c0f1c..2430eceb8 100644
--- a/lib/puppet-lint/plugins/check_variables/variable_is_lowercase.rb
+++ b/lib/puppet-lint/plugins/check_variables/variable_is_lowercase.rb
@@ -9,7 +9,7 @@ def check
     tokens.select { |r|
       VARIABLE_LOWERCASE_TYPES.include?(r.type)
     }.each do |token|
-      next unless token.value.gsub(%r{\[.+?\]}, '') =~ %r{[A-Z]}
+      next unless token.value.gsub(%r{\[.+?\]}, '').match?(%r{[A-Z]})
 
       notify(
         :warning,
diff --git a/lib/puppet-lint/plugins/check_whitespace/arrow_alignment.rb b/lib/puppet-lint/plugins/check_whitespace/arrow_alignment.rb
index d687179b8..6f56d0d07 100644
--- a/lib/puppet-lint/plugins/check_whitespace/arrow_alignment.rb
+++ b/lib/puppet-lint/plugins/check_whitespace/arrow_alignment.rb
@@ -103,7 +103,7 @@ def fix(problem)
       problem[:token].prev_code_token.prev_token.value = ' ' * problem[:newline_indent]
 
       end_param_idx = tokens.index(problem[:token].prev_code_token)
-      start_param_idx = tokens.index(problem[:token].prev_token_of([:INDENT, :NEWLINE]))
+      start_param_idx = tokens.index(problem[:token].prev_token_of(%i[INDENT NEWLINE]))
       param_length = tokens[start_param_idx..end_param_idx].map { |r| r.to_manifest.length }.reduce(0) { |sum, x| sum + x } + 1
       new_ws_len = problem[:arrow_column] - param_length
     else
@@ -115,7 +115,7 @@ def fix(problem)
       new_ws_len += (problem[:arrow_column] - problem[:token].column)
     end
 
-    raise PuppetLint::NoFix if new_ws_len < 0
+    raise PuppetLint::NoFix if new_ws_len.negative?
     new_ws = ' ' * new_ws_len
 
     if problem[:token].prev_token.type == :WHITESPACE
diff --git a/lib/puppet-lint/plugins/check_whitespace/trailing_whitespace.rb b/lib/puppet-lint/plugins/check_whitespace/trailing_whitespace.rb
index b19996e10..07e810100 100644
--- a/lib/puppet-lint/plugins/check_whitespace/trailing_whitespace.rb
+++ b/lib/puppet-lint/plugins/check_whitespace/trailing_whitespace.rb
@@ -5,7 +5,7 @@
 PuppetLint.new_check(:trailing_whitespace) do
   def check
     tokens.select { |token|
-      [:WHITESPACE, :INDENT].include?(token.type)
+      %i[WHITESPACE INDENT].include?(token.type)
     }.select { |token|
       token.next_token.nil? || token.next_token.type == :NEWLINE
     }.each do |token|
@@ -25,7 +25,7 @@ def fix(problem)
     prev_token = problem[:token].prev_token
     next_token = problem[:token].next_token
     prev_token.next_token = next_token
-    next_token.prev_token = prev_token unless next_token.nil?
+    next_token&.prev_token = prev_token
     tokens.delete(problem[:token])
   end
 end
diff --git a/lib/puppet-lint/tasks/puppet-lint.rb b/lib/puppet-lint/tasks/puppet-lint.rb
index 1b3efdb1b..c23569b80 100644
--- a/lib/puppet-lint/tasks/puppet-lint.rb
+++ b/lib/puppet-lint/tasks/puppet-lint.rb
@@ -50,7 +50,7 @@ def initialize(*args, &task_block)
     def define(args, &task_block)
       desc 'Run puppet-lint'
 
-      task_block.call(*[self, args].slice(0, task_block.arity)) if task_block
+      task_block&.call(*[self, args].slice(0, task_block.arity))
 
       # clear any (auto-)pre-existing task
       Rake::Task[@name].clear if Rake::Task.task_defined?(@name)
diff --git a/spec/puppet-lint/checks_spec.rb b/spec/puppet-lint/checks_spec.rb
index 758a483ee..57026c9f7 100644
--- a/spec/puppet-lint/checks_spec.rb
+++ b/spec/puppet-lint/checks_spec.rb
@@ -84,7 +84,7 @@
     end
 
     context 'when there are checks enabled' do
-      let(:enabled_checks) { [:arrow_alignment, :hard_tabs] }
+      let(:enabled_checks) { %i[arrow_alignment hard_tabs] }
       let(:enabled_check_classes) { enabled_checks.map { |r| PuppetLint.configuration.check_object[r] } }
       let(:disabled_checks) { PuppetLint.configuration.checks - enabled_checks }
       let(:disabled_check_classes) { disabled_checks.map { |r| PuppetLint.configuration.check_object[r] } }
@@ -194,7 +194,7 @@
   describe '#enabled_checks' do
     subject(:enabled_checks) { instance.enabled_checks }
 
-    let(:expected_enabled_checks) { [:arrow_alignment, :trailing_whitespace] }
+    let(:expected_enabled_checks) { %i[arrow_alignment trailing_whitespace] }
 
     before do
       PuppetLint.configuration.checks.each do |check|