diff --git a/.rubocop.yml b/.rubocop.yml
index 6b9aa9f..1c0f832 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,5 +1,5 @@
 inherit_from:
-  - https://shopify.github.io/ruby-style-guide/rubocop.yml
+  - 'https://shopify.github.io/ruby-style-guide/rubocop.yml'
   - .rubocop_todo.yml
 
 require: rubocop-performance
@@ -8,9 +8,10 @@ Performance:
   Enabled: true
 
 AllCops:
+  TargetRubyVersion: 2.4
   Exclude:
     - 'vendor/bundle/**/*'
-      
+
 Naming/MethodName:
   Exclude:
-    - 'example/server/liquid_servlet.rb'
\ No newline at end of file
+    - 'example/server/liquid_servlet.rb'
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index c1e39a4..70fce22 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -6,26 +6,6 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 2
-Lint/AmbiguousOperator:
-  Exclude:
-    - 'test/unit/condition_unit_test.rb'
-
-# Offense count: 21
-# Configuration parameters: AllowSafeAssignment.
-Lint/AssignmentInCondition:
-  Exclude:
-    - 'lib/liquid/block_body.rb'
-    - 'lib/liquid/lexer.rb'
-    - 'lib/liquid/standardfilters.rb'
-    - 'lib/liquid/tags/for.rb'
-    - 'lib/liquid/tags/if.rb'
-    - 'lib/liquid/tags/raw.rb'
-    - 'lib/liquid/variable.rb'
-    - 'performance/profile.rb'
-    - 'test/test_helper.rb'
-    - 'test/unit/tokenizer_unit_test.rb'
-
 # Offense count: 2
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
@@ -34,17 +14,6 @@ Lint/InheritException:
   Exclude:
     - 'lib/liquid/interrupts.rb'
 
-# Offense count: 2
-Lint/UselessAssignment:
-  Exclude:
-    - 'performance/shopify/database.rb'
-
-# Offense count: 1
-# Configuration parameters: CheckForMethodsWithNoSideEffects.
-Lint/Void:
-  Exclude:
-    - 'lib/liquid/parse_context.rb'
-
 # Offense count: 98
 # Cop supports --auto-correct.
 # Configuration parameters: AutoCorrect, AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
@@ -57,19 +26,4 @@ Style/ClassVars:
   Exclude:
     - 'lib/liquid/condition.rb'
     - 'lib/liquid/strainer.rb'
-    - 'lib/liquid/template.rb'
-
-# Offense count: 1
-# Configuration parameters: AllowCoercion.
-Style/DateTime:
-  Exclude:
-    - 'test/unit/context_unit_test.rb'
-
-# Offense count: 9
-# Cop supports --auto-correct.
-# Configuration parameters: AllowAsExpressionSeparator.
-Style/Semicolon:
-  Exclude:
-    - 'test/integration/error_handling_test.rb'
-    - 'test/integration/template_test.rb'
-    - 'test/unit/context_unit_test.rb'
+    - 'lib/liquid/template.rb'
\ No newline at end of file
diff --git a/lib/liquid/block_body.rb b/lib/liquid/block_body.rb
index 4faba0b..2f3433e 100644
--- a/lib/liquid/block_body.rb
+++ b/lib/liquid/block_body.rb
@@ -27,7 +27,7 @@ module Liquid
     end
 
     private def parse_for_liquid_tag(tokenizer, parse_context)
-      while token = tokenizer.shift
+      while (token = tokenizer.shift)
         unless token.empty? || token =~ WHITESPACE_OR_NOTHING
           unless token =~ LIQUID_TAG_TOKEN
             # line isn't empty but didn't match tag syntax, yield and let the
@@ -36,7 +36,7 @@ module Liquid
           end
           tag_name = Regexp.last_match(1)
           markup = Regexp.last_match(2)
-          unless tag = registered_tags[tag_name]
+          unless (tag = registered_tags[tag_name])
             # end parsing if we reach an unknown tag and let the caller decide
             # determine how to proceed
             return yield tag_name, markup
@@ -52,7 +52,7 @@ module Liquid
     end
 
     private def parse_for_document(tokenizer, parse_context, &block)
-      while token = tokenizer.shift
+      while (token = tokenizer.shift)
         next if token.empty?
         case
         when token.start_with?(TAG_START_STRING)
@@ -74,7 +74,7 @@ module Liquid
             next parse_for_liquid_tag(liquid_tag_tokenizer, parse_context, &block)
           end
 
-          unless tag = registered_tags[tag_name]
+          unless (tag = registered_tags[tag_name])
             # end parsing if we reach an unknown tag and let the caller decide
             # determine how to proceed
             return yield tag_name, markup
@@ -122,7 +122,7 @@ module Liquid
       context.resource_limits.render_score += @nodelist.length
 
       idx = 0
-      while node = @nodelist[idx]
+      while (node = @nodelist[idx])
         previous_output_size = output.bytesize
 
         case node
diff --git a/lib/liquid/file_system.rb b/lib/liquid/file_system.rb
index b2093ae..27ab632 100644
--- a/lib/liquid/file_system.rb
+++ b/lib/liquid/file_system.rb
@@ -59,7 +59,7 @@ module Liquid
     end
 
     def full_path(template_path)
-      raise FileSystemError, "Illegal template name '#{template_path}'" unless template_path =~ %r{\A[^./][a-zA-Z0-9_/]+\z}
+      raise FileSystemError, "Illegal template name '#{template_path}'" unless %r{\A[^./][a-zA-Z0-9_/]+\z}.match?(template_path)
 
       full_path = if template_path.include?('/')
         File.join(root, File.dirname(template_path), @pattern % File.basename(template_path))
diff --git a/lib/liquid/lexer.rb b/lib/liquid/lexer.rb
index 04e0c11..a251c3e 100644
--- a/lib/liquid/lexer.rb
+++ b/lib/liquid/lexer.rb
@@ -33,15 +33,21 @@ module Liquid
       until @ss.eos?
         @ss.skip(WHITESPACE_OR_NOTHING)
         break if @ss.eos?
-        tok = if t = @ss.scan(COMPARISON_OPERATOR) then [:comparison, t]
-        elsif t = @ss.scan(SINGLE_STRING_LITERAL) then [:string, t]
-        elsif t = @ss.scan(DOUBLE_STRING_LITERAL) then [:string, t]
-        elsif t = @ss.scan(NUMBER_LITERAL) then [:number, t]
-        elsif t = @ss.scan(IDENTIFIER) then [:id, t]
-        elsif t = @ss.scan(DOTDOT) then [:dotdot, t]
+        tok = if (t = @ss.scan(COMPARISON_OPERATOR))
+          [:comparison, t]
+        elsif (t = @ss.scan(SINGLE_STRING_LITERAL))
+          [:string, t]
+        elsif (t = @ss.scan(DOUBLE_STRING_LITERAL))
+          [:string, t]
+        elsif (t = @ss.scan(NUMBER_LITERAL))
+          [:number, t]
+        elsif (t = @ss.scan(IDENTIFIER))
+          [:id, t]
+        elsif (t = @ss.scan(DOTDOT))
+          [:dotdot, t]
         else
           c = @ss.getch
-          if s = SPECIALS[c]
+          if (s = SPECIALS[c])
             [s, c]
           else
             raise SyntaxError, "Unexpected character #{c}"
diff --git a/lib/liquid/parse_context.rb b/lib/liquid/parse_context.rb
index 2da3ad7..4afdbe5 100644
--- a/lib/liquid/parse_context.rb
+++ b/lib/liquid/parse_context.rb
@@ -21,7 +21,6 @@ module Liquid
       @partial = value
       @options = value ? partial_options : @template_options
       @error_mode = @options[:error_mode] || Template.error_mode
-      value
     end
 
     def partial_options
diff --git a/lib/liquid/standardfilters.rb b/lib/liquid/standardfilters.rb
index 517857a..6855cd2 100644
--- a/lib/liquid/standardfilters.rb
+++ b/lib/liquid/standardfilters.rb
@@ -327,7 +327,7 @@ module Liquid
     def date(input, format)
       return input if format.to_s.empty?
 
-      return input unless date = Utils.to_date(input)
+      return input unless (date = Utils.to_date(input))
 
       date.strftime(format.to_s)
     end
diff --git a/lib/liquid/static_registers.rb b/lib/liquid/static_registers.rb
index 6f22f70..06c52ab 100644
--- a/lib/liquid/static_registers.rb
+++ b/lib/liquid/static_registers.rb
@@ -2,10 +2,10 @@
 
 module Liquid
   class StaticRegisters
-    attr_reader :static_registers, :registers
+    attr_reader :static, :registers
 
     def initialize(registers = {})
-      @static_registers = registers.is_a?(StaticRegisters) ? registers.static_registers : registers.freeze
+      @static = registers.is_a?(StaticRegisters) ? registers.static : registers
       @registers = {}
     end
 
@@ -17,7 +17,7 @@ module Liquid
       if @registers.key?(key)
         @registers[key]
       else
-        @static_registers[key]
+        @static[key]
       end
     end
 
@@ -30,7 +30,7 @@ module Liquid
     end
 
     def key?(key)
-      @registers.key?(key) || @static_registers.key?(key)
+      @registers.key?(key) || @static.key?(key)
     end
   end
 end
diff --git a/lib/liquid/tags/for.rb b/lib/liquid/tags/for.rb
index 2819337..b63b9e1 100644
--- a/lib/liquid/tags/for.rb
+++ b/lib/liquid/tags/for.rb
@@ -111,7 +111,7 @@ module Liquid
       @reversed = p.id?('reversed')
 
       while p.look(:id) && p.look(:colon, 1)
-        unless attribute = p.id?('limit') || p.id?('offset')
+        unless (attribute = p.id?('limit') || p.id?('offset'))
           raise SyntaxError, options[:locale].t("errors.syntax.for_invalid_attribute")
         end
         p.consume
diff --git a/lib/liquid/tags/if.rb b/lib/liquid/tags/if.rb
index db1a283..50cb334 100644
--- a/lib/liquid/tags/if.rb
+++ b/lib/liquid/tags/if.rb
@@ -94,7 +94,7 @@ module Liquid
     def parse_binary_comparisons(p)
       condition = parse_comparison(p)
       first_condition = condition
-      while op = (p.id?('and') || p.id?('or'))
+      while (op = (p.id?('and') || p.id?('or')))
         child_condition = parse_comparison(p)
         condition.send(op, child_condition)
         condition = child_condition
@@ -104,7 +104,7 @@ module Liquid
 
     def parse_comparison(p)
       a = Expression.parse(p.expression)
-      if op = p.consume?(:comparison)
+      if (op = p.consume?(:comparison))
         b = Expression.parse(p.expression)
         Condition.new(a, op, b)
       else
diff --git a/lib/liquid/tags/raw.rb b/lib/liquid/tags/raw.rb
index 996a34c..e4b2a6a 100644
--- a/lib/liquid/tags/raw.rb
+++ b/lib/liquid/tags/raw.rb
@@ -13,7 +13,7 @@ module Liquid
 
     def parse(tokens)
       @body = +''
-      while token = tokens.shift
+      while (token = tokens.shift)
         if token =~ FULL_TOKEN_POSSIBLY_INVALID
           @body << Regexp.last_match(1) if Regexp.last_match(1) != ""
           return if block_delimiter == Regexp.last_match(2)
@@ -40,7 +40,7 @@ module Liquid
     protected
 
     def ensure_valid_markup(tag_name, markup, parse_context)
-      unless markup =~ SYNTAX
+      unless SYNTAX.match?(markup)
         raise SyntaxError, parse_context.locale.t("errors.syntax.tag_unexpected_args", tag: tag_name)
       end
     end
diff --git a/lib/liquid/utils.rb b/lib/liquid/utils.rb
index 406d667..709fb00 100644
--- a/lib/liquid/utils.rb
+++ b/lib/liquid/utils.rb
@@ -52,7 +52,7 @@ module Liquid
       when Numeric
         obj
       when String
-        obj.strip =~ /\A-?\d+\.\d+\z/ ? BigDecimal(obj) : obj.to_i
+        /\A-?\d+\.\d+\z/.match?(obj.strip) ? BigDecimal(obj) : obj.to_i
       else
         if obj.respond_to?(:to_number)
           obj.to_number
diff --git a/lib/liquid/variable.rb b/lib/liquid/variable.rb
index d18c9d0..2ede9e8 100644
--- a/lib/liquid/variable.rb
+++ b/lib/liquid/variable.rb
@@ -110,7 +110,7 @@ module Liquid
       filter_args = []
       keyword_args = nil
       unparsed_args.each do |a|
-        if matches = a.match(JUST_TAG_ATTRIBUTES)
+        if (matches = a.match(JUST_TAG_ATTRIBUTES))
           keyword_args ||= {}
           keyword_args[matches[1]] = Expression.parse(matches[2])
         else
diff --git a/performance/profile.rb b/performance/profile.rb
index 101f6e5..7074077 100644
--- a/performance/profile.rb
+++ b/performance/profile.rb
@@ -15,7 +15,7 @@ profiler.run
     end
   end
 
-  if profile_type == :cpu && graph_filename = ENV['GRAPH_FILENAME']
+  if profile_type == :cpu && (graph_filename = ENV['GRAPH_FILENAME'])
     File.open(graph_filename, 'w') do |f|
       StackProf::Report.new(results).print_graphviz(nil, f)
     end
diff --git a/performance/shopify/database.rb b/performance/shopify/database.rb
index 9836cd4..2db6d30 100644
--- a/performance/shopify/database.rb
+++ b/performance/shopify/database.rb
@@ -32,8 +32,8 @@ module Database
       db['article']    = db['blog']['articles'].first
 
       db['cart']       = {
-        'total_price' => db['line_items'].values.inject(0) { |sum, item| sum += item['line_price'] * item['quantity'] },
-        'item_count' => db['line_items'].values.inject(0) { |sum, item| sum += item['quantity'] },
+        'total_price' => db['line_items'].values.inject(0) { |sum, item| sum + item['line_price'] * item['quantity'] },
+        'item_count' => db['line_items'].values.inject(0) { |sum, item| sum + item['quantity'] },
         'items' => db['line_items'].values,
       }
 
diff --git a/test/integration/error_handling_test.rb b/test/integration/error_handling_test.rb
index 265632c..7abaec0 100644
--- a/test/integration/error_handling_test.rb
+++ b/test/integration/error_handling_test.rb
@@ -211,7 +211,10 @@ class ErrorHandlingTest < Minitest::Test
   def test_setting_default_exception_renderer
     old_exception_renderer = Liquid::Template.default_exception_renderer
     exceptions = []
-    Liquid::Template.default_exception_renderer = ->(e) { exceptions << e; '' }
+    Liquid::Template.default_exception_renderer = ->(e) {
+      exceptions << e
+      ''
+    }
     template = Liquid::Template.parse('This is a runtime error: {{ errors.argument_error }}')
 
     output = template.render('errors' => ErrorDrop.new)
@@ -225,7 +228,10 @@ class ErrorHandlingTest < Minitest::Test
   def test_exception_renderer_exposing_non_liquid_error
     template = Liquid::Template.parse('This is a runtime error: {{ errors.runtime_error }}', line_numbers: true)
     exceptions = []
-    handler = ->(e) { exceptions << e; e.cause }
+    handler = ->(e) {
+      exceptions << e
+      e.cause
+    }
 
     output = template.render({ 'errors' => ErrorDrop.new }, exception_renderer: handler)
 
diff --git a/test/integration/template_test.rb b/test/integration/template_test.rb
index 75dd95b..48549f5 100644
--- a/test/integration/template_test.rb
+++ b/test/integration/template_test.rb
@@ -81,7 +81,10 @@ class TemplateTest < Minitest::Test
 
   def test_lambda_is_called_once_from_persistent_assigns_over_multiple_parses_and_renders
     t = Template.new
-    t.assigns['number'] = -> { @global ||= 0; @global += 1 }
+    t.assigns['number'] = -> {
+      @global ||= 0
+      @global += 1
+    }
     assert_equal '1', t.parse("{{number}}").render!
     assert_equal '1', t.parse("{{number}}").render!
     assert_equal '1', t.render!
@@ -90,7 +93,10 @@ class TemplateTest < Minitest::Test
 
   def test_lambda_is_called_once_from_custom_assigns_over_multiple_parses_and_renders
     t = Template.new
-    assigns = { 'number' => -> { @global ||= 0; @global += 1 } }
+    assigns = { 'number' => -> {
+                              @global ||= 0
+                              @global += 1
+                            } }
     assert_equal '1', t.parse("{{number}}").render!(assigns)
     assert_equal '1', t.parse("{{number}}").render!(assigns)
     assert_equal '1', t.render!(assigns)
@@ -237,7 +243,10 @@ class TemplateTest < Minitest::Test
 
   def test_exception_renderer_that_returns_string
     exception = nil
-    handler = ->(e) { exception = e; '<!-- error -->' }
+    handler = ->(e) {
+      exception = e
+      '<!-- error -->'
+    }
 
     output = Template.parse("{{ 1 | divided_by: 0 }}").render({}, exception_renderer: handler)
 
@@ -248,7 +257,10 @@ class TemplateTest < Minitest::Test
   def test_exception_renderer_that_raises
     exception = nil
     assert_raises(Liquid::ZeroDivisionError) do
-      Template.parse("{{ 1 | divided_by: 0 }}").render({}, exception_renderer: ->(e) { exception = e; raise })
+      Template.parse("{{ 1 | divided_by: 0 }}").render({}, exception_renderer: ->(e) {
+                                                                                 exception = e
+                                                                                 raise
+                                                                               })
     end
     assert exception.is_a?(Liquid::ZeroDivisionError)
   end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index d7a6641..9606ef8 100755
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -9,7 +9,7 @@ require 'liquid.rb'
 require 'liquid/profiler'
 
 mode = :strict
-if env_mode = ENV['LIQUID_PARSER_MODE']
+if (env_mode = ENV['LIQUID_PARSER_MODE'])
   puts "-- #{env_mode.upcase} ERROR MODE"
   mode = env_mode.to_sym
 end
diff --git a/test/unit/condition_unit_test.rb b/test/unit/condition_unit_test.rb
index 69f6b90..8d4e02f 100644
--- a/test/unit/condition_unit_test.rb
+++ b/test/unit/condition_unit_test.rb
@@ -26,9 +26,9 @@ class ConditionUnitTest < Minitest::Test
     assert_evaluates_true 1, '<=', 1
     # negative numbers
     assert_evaluates_true 1, '>', -1
-    assert_evaluates_true -1, '<', 1
+    assert_evaluates_true(-1, '<', 1)
     assert_evaluates_true 1.0, '>', -1.0
-    assert_evaluates_true -1.0, '<', 1.0
+    assert_evaluates_true(-1.0, '<', 1.0)
   end
 
   def test_default_operators_evalute_false
diff --git a/test/unit/context_unit_test.rb b/test/unit/context_unit_test.rb
index fe790cf..3b460d7 100644
--- a/test/unit/context_unit_test.rb
+++ b/test/unit/context_unit_test.rb
@@ -85,7 +85,7 @@ class ContextUnitTest < Minitest::Test
     @context['date'] = Date.today
     assert_equal Date.today, @context['date']
 
-    now = DateTime.now
+    now = Time.now
     @context['datetime'] = now
     assert_equal now, @context['datetime']
 
@@ -405,7 +405,11 @@ class ContextUnitTest < Minitest::Test
   end
 
   def test_lambda_is_called_once
-    @context['callcount'] = proc { @global ||= 0; @global += 1; @global.to_s }
+    @context['callcount'] = proc {
+      @global ||= 0
+      @global += 1
+      @global.to_s
+    }
 
     assert_equal '1', @context['callcount']
     assert_equal '1', @context['callcount']
@@ -415,7 +419,11 @@ class ContextUnitTest < Minitest::Test
   end
 
   def test_nested_lambda_is_called_once
-    @context['callcount'] = { "lambda" => proc { @global ||= 0; @global += 1; @global.to_s } }
+    @context['callcount'] = { "lambda" => proc {
+                                            @global ||= 0
+                                            @global += 1
+                                            @global.to_s
+                                          } }
 
     assert_equal '1', @context['callcount.lambda']
     assert_equal '1', @context['callcount.lambda']
@@ -425,7 +433,11 @@ class ContextUnitTest < Minitest::Test
   end
 
   def test_lambda_in_array_is_called_once
-    @context['callcount'] = [1, 2, proc { @global ||= 0; @global += 1; @global.to_s }, 4, 5]
+    @context['callcount'] = [1, 2, proc {
+                                     @global ||= 0
+                                     @global += 1
+                                     @global.to_s
+                                   }, 4, 5]
 
     assert_equal '1', @context['callcount[2]']
     assert_equal '1', @context['callcount[2]']
diff --git a/test/unit/static_registers_unit_test.rb b/test/unit/static_registers_unit_test.rb
index 0db80cd..125440f 100644
--- a/test/unit/static_registers_unit_test.rb
+++ b/test/unit/static_registers_unit_test.rb
@@ -82,7 +82,7 @@ class StaticRegistersUnitTest < Minitest::Test
     static_register["two"] = 4
     static_register[true] = "foo"
 
-    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static_registers)
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static)
     assert_equal({ nil => false, "two" => 4, true => "foo" }, static_register.registers)
 
     static_register
@@ -109,7 +109,7 @@ class StaticRegistersUnitTest < Minitest::Test
     assert_nil static_register.delete(:one)
 
     assert_equal({}, static_register.registers)
-    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static_registers)
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static)
   end
 
   def test_fetch_with_static
@@ -135,10 +135,10 @@ class StaticRegistersUnitTest < Minitest::Test
     assert_equal true, static_register.key?(true)
   end
 
-  def test_static_register_frozen
+  def test_static_register_can_be_frozen
     static_register = set_with_static
 
-    static = static_register.static_registers
+    static = static_register.static.freeze
 
     assert_raises(RuntimeError) do
       static["two"] = "foo"
@@ -176,9 +176,9 @@ class StaticRegistersUnitTest < Minitest::Test
     assert_equal({ "one" => 1, "two" => 2, "three" => 3 }, static_register.registers)
     assert_equal({ "one" => 4, "two" => 5, "three" => 6 }, new_register.registers)
     assert_equal({ "one" => 7, "two" => 8, "three" => 9 }, newest_register.registers)
-    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static_registers)
-    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, new_register.static_registers)
-    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, newest_register.static_registers)
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static)
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, new_register.static)
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, newest_register.static)
   end
 
   def test_multiple_instances_are_unique
@@ -204,8 +204,45 @@ class StaticRegistersUnitTest < Minitest::Test
     assert_equal({ "one" => 1, "two" => 2, "three" => 3 }, static_register.registers)
     assert_equal({ "one" => 4, "two" => 5, "three" => 6 }, new_register.registers)
     assert_equal({ "one" => 7, "two" => 8, "three" => 9 }, newest_register.registers)
-    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static_registers)
-    assert_equal({ foo: :bar }, new_register.static_registers)
-    assert_equal({ bar: :foo }, newest_register.static_registers)
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static)
+    assert_equal({ foo: :bar }, new_register.static)
+    assert_equal({ bar: :foo }, newest_register.static)
+  end
+
+  def test_can_update_static_directly_and_updates_all_instances
+    static_register = StaticRegisters.new(nil => true, 1 => :one, :one => "one", "two" => 3, false => nil)
+    static_register["one"] = 1
+    static_register["two"] = 2
+    static_register["three"] = 3
+
+    new_register = StaticRegisters.new(static_register)
+    assert_equal({}, new_register.registers)
+
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil }, static_register.static)
+
+    new_register["one"] = 4
+    new_register["two"] = 5
+    new_register["three"] = 6
+    new_register.static["four"] = 10
+
+    newest_register = StaticRegisters.new(new_register)
+    assert_equal({}, newest_register.registers)
+
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil, "four" => 10 }, new_register.static)
+
+    newest_register["one"] = 7
+    newest_register["two"] = 8
+    newest_register["three"] = 9
+    new_register.static["four"] = 5
+    new_register.static["five"] = 15
+
+    assert_equal({ "one" => 1, "two" => 2, "three" => 3 }, static_register.registers)
+    assert_equal({ "one" => 4, "two" => 5, "three" => 6 }, new_register.registers)
+    assert_equal({ "one" => 7, "two" => 8, "three" => 9 }, newest_register.registers)
+
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil, "four" => 5, "five" => 15 }, newest_register.static)
+
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil, "four" => 5, "five" => 15 }, static_register.static)
+    assert_equal({ nil => true, 1 => :one, :one => "one", "two" => 3, false => nil, "four" => 5, "five" => 15 }, new_register.static)
   end
 end
diff --git a/test/unit/tokenizer_unit_test.rb b/test/unit/tokenizer_unit_test.rb
index d094aa1..44342d6 100644
--- a/test/unit/tokenizer_unit_test.rb
+++ b/test/unit/tokenizer_unit_test.rb
@@ -35,7 +35,7 @@ class TokenizerTest < Minitest::Test
   def tokenize(source)
     tokenizer = Liquid::Tokenizer.new(source)
     tokens = []
-    while t = tokenizer.shift
+    while (t = tokenizer.shift)
       tokens << t
     end
     tokens