vm_method.c: NameError at refined method alias

* vm_method.c (rb_alias): raise a NameError when creating alias to
  a refined method if the original method of the refined method is
  not defined.  [ruby-core:67523] [Bug #10731]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49221 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Mon Jan 12 16:45:46 2015  Seiei Higa  <hanachin@gmail.com>
+
+	* vm_method.c (rb_alias): raise a NameError when creating alias to
+	  a refined method if the original method of the refined method is
+	  not defined.  [ruby-core:67523] [Bug #10731]
+
 Mon Jan 12 13:53:17 2015  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
 
 	* math.c (math_atan2): improve documentation.

test/ruby/test_refinement.rb

@@ -1192,6 +1192,31 @@ class TestRefinement < Test::Unit::TestCase
     end;
   end
 
+  def test_alias_refined_method
+    assert_separately([], <<-"end;")
+    bug10731 = '[ruby-core:67523] [Bug #10731]'
+
+    class C
+    end
+
+    module RefinementBug
+      refine C do
+        def foo
+        end
+
+        def bar
+        end
+      end
+    end
+
+    assert_raise(NameError, bug10731) do
+      class C
+        alias foo bar
+      end
+    end
+    end;
+  end
+
   private
 
   def eval_using(mod, s)

vm_method.c

@@ -1278,7 +1278,9 @@ rb_alias(VALUE klass, ID name, ID def)
   again:
     orig_me = search_method(klass, def, &defined_class);
 
-    if (UNDEFINED_METHOD_ENTRY_P(orig_me)) {
+    if (UNDEFINED_METHOD_ENTRY_P(orig_me) ||
+	(orig_me->def->type == VM_METHOD_TYPE_REFINED &&
+	 UNDEFINED_METHOD_ENTRY_P(orig_me->def->body.orig_me))) {
 	if ((!RB_TYPE_P(klass, T_MODULE)) ||
 	    (orig_me = search_method(rb_cObject, def, 0),
 	     UNDEFINED_METHOD_ENTRY_P(orig_me))) {