diff --git a/lib/liquid/extensions.rb b/lib/liquid/extensions.rb
index 2752ba37..24fc8e3f 100644
--- a/lib/liquid/extensions.rb
+++ b/lib/liquid/extensions.rb
@@ -43,14 +43,20 @@ class Date  # :nodoc:
   end
 end
 
-def true.to_liquid  # :nodoc:
-  self
+class TrueClass
+  def to_liquid  # :nodoc:
+    self
+  end
 end
 
-def false.to_liquid # :nodoc:
-  self
+class FalseClass
+  def to_liquid # :nodoc:
+    self
+  end
 end
 
-def nil.to_liquid # :nodoc:
-  self
-end
\ No newline at end of file
+class NilClass
+  def to_liquid # :nodoc:
+    self
+  end
+end