diff --git a/lib/ddir/ast.rb b/lib/ddir/ast.rb
index d315459..aae3475 100644
--- a/lib/ddir/ast.rb
+++ b/lib/ddir/ast.rb
@@ -99,13 +99,6 @@ def classname
     end
 
 
-    class Null < Ast
-      def children
-        []
-      end
-    end
-
-
     class Body < Ast
       attr_accessor :expressions
 
@@ -328,13 +321,6 @@ def children
     end
 
 
-    class None < Ast
-      def children
-        []
-      end
-    end
-
-
     class Variable < Ast
       attr_accessor :name
 
diff --git a/lib/ddir/generate.rb b/lib/ddir/generate.rb
index cf5b6af..42bf226 100644
--- a/lib/ddir/generate.rb
+++ b/lib/ddir/generate.rb
@@ -107,9 +107,6 @@ def generate(ast, entry, indentation)
       when :required_param
         "#{ast.name}:"
 
-      when :none
-        ''
-
       else
         raise "CANNOT GENERATE #{ast.inspect}"
       end