2 files changed, 4 insertions, 2 deletions
diff --git a/mrbgems/mruby-enumerator/mrblib/enumerator.rb b/mrbgems/mruby-enumerator/mrblib/enumerator.rb
index 7ca1d5eb6..dbc7d3004 100644
--- a/mrbgems/mruby-enumerator/mrblib/enumerator.rb
+++ b/mrbgems/mruby-enumerator/mrblib/enumerator.rb
@@ -614,6 +614,9 @@ module Kernel
   #     enum.first(4) # => [1, 1, 1, 2]
   #
   def to_enum(meth=:each, *args)
+    unless self.respond_to?(meth)
+      raise ArgumentError, "undefined method #{meth}"
+    end
     Enumerator.new self, meth, *args
   end
   alias enum_for to_enum
diff --git a/mrbgems/mruby-enumerator/test/enumerator.rb b/mrbgems/mruby-enumerator/test/enumerator.rb
index 428ea0307..ef4970883 100644
--- a/mrbgems/mruby-enumerator/test/enumerator.rb
+++ b/mrbgems/mruby-enumerator/test/enumerator.rb
@@ -22,8 +22,7 @@ assert 'Enumerator.new' do
   assert_equal [1,2,3], Enumerator.new(@obj, :foo, 1,2,3).to_a
   assert_equal [1,2,3], Enumerator.new { |y| i = 0; loop { y << (i += 1) } }.take(3)
   assert_raise(ArgumentError) { Enumerator.new }
-  enum = @obj.to_enum
-  assert_raise(NoMethodError) { enum.each {} }
+  assert_raise(ArgumentError) { @obj.to_enum }
 
   # examples
   fib = Enumerator.new do |y|