diff --git a/Gemfile b/Gemfile
index f1ca2274..e584ffa4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,6 @@ source "https://rubygems.org"
 gemspec
 
 # Development dependencies
-gem "bundler", ">= 2.5.23"
 gem "debug", ">= 1.11.1"
 gem "guard-rspec", "~> 4.0"
 gem "rake", "~> 13.0"
diff --git a/bin/verify-sample-code b/bin/verify-sample-code
index b1c73a62..ad259441 100755
--- a/bin/verify-sample-code
+++ b/bin/verify-sample-code
@@ -13,6 +13,7 @@ repos = {
         "spec/rspec/core/formatters/progress_formatter_spec.rb",
         "spec/rspec/core/formatters_spec.rb",
         "spec/rspec/core/formatters/documentation_formatter_spec.rb",
+        "spec/rspec/core/memoized_helpers_spec.rb",
       ].join(","),
     },
   },
diff --git a/lib/rufo/erb_formatter.rb b/lib/rufo/erb_formatter.rb
index 3f146c45..2509c619 100644
--- a/lib/rufo/erb_formatter.rb
+++ b/lib/rufo/erb_formatter.rb
@@ -126,6 +126,7 @@ def format_affix(affix, levels, type)
   end
 
   CODE_BLOCK_KEYWORDS = %w[BEGIN END begin case class def do else elsif end ensure for if module rescue unless until while]
+  private_constant :CODE_BLOCK_KEYWORDS
 
   def code_block_token?(token)
     _, kind, value = token
diff --git a/lib/rufo/formatter.rb b/lib/rufo/formatter.rb
index 2a16febc..5adbbf39 100644
--- a/lib/rufo/formatter.rb
+++ b/lib/rufo/formatter.rb
@@ -646,7 +646,7 @@ def format_simple_string(node)
   def with_unmodifiable_string_lines
     line = @line
     yield
-    (line + 1..@line).each do |i|
+    ((line + 1)..@line).each do |i|
       @unmodifiable_string_lines[i] = true
     end
   end
@@ -4041,7 +4041,7 @@ def dedent_calls
       next unless first_paren_end_line == last_line
 
       diff = first_param_indent - indent
-      (first_line + 1..last_line).each do |line|
+      ((first_line + 1)..last_line).each do |line|
         @line_to_call_info.delete(line)
 
         next if @unmodifiable_string_lines[line]
@@ -4068,7 +4068,7 @@ def indent_literals
 
     modified_lines = []
     @literal_indents.each do |first_line, last_line, indent|
-      (first_line + 1..last_line).each do |line|
+      ((first_line + 1)..last_line).each do |line|
         next if @unmodifiable_string_lines[line]
 
         current_line = lines[line]
@@ -4117,7 +4117,7 @@ def do_align(components, scope)
 
         # Move all lines affected by the assignment shift
         if scope == :assign && (range = @assignments_ranges[line])
-          (line + 1..range).each do |line_number|
+          ((line + 1)..range).each do |line_number|
             lines[line_number] = "#{filler}#{lines[line_number]}"
 
             # And move other elements too if applicable