lib/memoist.rb in memoist-0.16.0 vs lib/memoist.rb in memoist-0.16.1

@@ -1,9 +1,8 @@
 # frozen_string_literal: true
 
 require 'memoist/version'
-require 'memoist/core_ext/singleton_class'
 
 module Memoist
   def self.extended(extender)
     Memoist.memoist_eval(extender) do
       unless singleton_class.method_defined?(:memoized_methods)
@@ -37,12 +36,14 @@
       '_unmemoized'.freeze
     end
   end
 
   def self.escape_punctuation(string)
-    string = string.is_a?(String) ? string.dup : string.to_s
+    string = string.to_s
 
     return string unless string.end_with?('?'.freeze, '!'.freeze)
+
+    string = string.dup if string.frozen?
 
     # A String can't end in both ? and !
     if string.sub!(/\?\Z/, '_query'.freeze)
     else
       string.sub!(/!\Z/, '_bang'.freeze)