From 70d8e6cf22515bfbf15bd283726ce9b72730164d Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Sun, 27 Nov 2016 11:07:27 +0000
Subject: [PATCH] object.c: no TypeError at special const dup

* object.c (rb_obj_dup): no longer raise a TypeError for special
  constants, and return itself instead.  [Feature#12979]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56906 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 object.c                                | 2 +-
 test/ruby/test_object.rb                | 6 +++---
 test/rubygems/test_gem_specification.rb | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/object.c b/object.c
index 05bef4df28..7075e13683 100644
--- a/object.c
+++ b/object.c
@@ -423,7 +423,7 @@ rb_obj_dup(VALUE obj)
     VALUE dup;
 
     if (rb_special_const_p(obj)) {
-        rb_raise(rb_eTypeError, "can't dup %s", rb_obj_classname(obj));
+	return obj;
     }
     dup = rb_obj_alloc(rb_obj_class(obj));
     init_copy(dup, obj);
diff --git a/test/ruby/test_object.rb b/test/ruby/test_object.rb
index 7b3defa011..2f80bc6ffb 100644
--- a/test/ruby/test_object.rb
+++ b/test/ruby/test_object.rb
@@ -19,9 +19,9 @@ class TestObject < Test::Unit::TestCase
   end
 
   def test_dup
-    assert_raise(TypeError) { 1.dup }
-    assert_raise(TypeError) { true.dup }
-    assert_raise(TypeError) { nil.dup }
+    assert_equal 1, 1.dup
+    assert_equal true, true.dup
+    assert_equal nil, nil.dup
 
     assert_raise(TypeError) do
       Object.new.instance_eval { initialize_copy(1) }
diff --git a/test/rubygems/test_gem_specification.rb b/test/rubygems/test_gem_specification.rb
index 87f0f360d7..2c0ea770b5 100644
--- a/test/rubygems/test_gem_specification.rb
+++ b/test/rubygems/test_gem_specification.rb
@@ -1260,7 +1260,7 @@ dependencies: []
       s.version = '1'
     end
 
-    spec.instance_variable_set :@licenses, :blah
+    spec.instance_variable_set :@licenses, Object.new.singleton_class
     spec.loaded_from = '/path/to/file'
 
     e = assert_raises Gem::FormatException do