Work around broken p-methods in gemified sorted_set

knu/sorted_set#2

lib/character_set/ruby_fallback/set_methods.rb

@@ -23,8 +23,8 @@ def #{mthd}(enum, &block)
         RUBY
       end
 
-      %i[<< === add add? clear collect! delete delete? delete_if
-         each filter! hash include? map! member? keep_if reject!
+      %i[<< add add? clear collect! delete delete? delete_if
+         each filter! hash map! keep_if reject!
          select! subtract].each do |mthd|
         class_eval <<-RUBY, __FILE__, __LINE__ + 1
           def #{mthd}(*args, &block)
@@ -34,6 +34,15 @@ def #{mthd}(*args, &block)
         RUBY
       end
 
+      # revert if https://github.com/knu/sorted_set/issues/2 is resolved
+      %i[=== include? member?].each do |mthd|
+        class_eval <<-RUBY, __FILE__, __LINE__ + 1
+          def #{mthd}(*args, &block)
+            !!@__set.#{mthd}(*args, &block)
+          end
+        RUBY
+      end
+
       %i[& + - ^ | difference intersection union].each do |mthd|
         class_eval <<-RUBY, __FILE__, __LINE__ + 1
           def #{mthd}(enum, &block)