merge revision(s) 66938: [Backport #15488]

	Fix `Module#const_defined?` on inherited constants

	[Fix GH-2061]

	From: manga_osyo <manga.osyo@gmail.com>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_6@66939 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 13 insertions, 3 deletions

diff --git a/object.c b/object.c
index 1c0ddfb356..4f844be5a3 100644
--- a/object.c
+++ b/object.c
@@ -2688,7 +2688,6 @@ rb_mod_const_defined(int argc, VALUE *argv, VALUE mod)
 		return Qfalse;
 	    mod = rb_const_get_at(mod, id);
 	}
-	recur = Qfalse;
 
 	if (p < pend && !RB_TYPE_P(mod, T_MODULE) && !RB_TYPE_P(mod, T_CLASS)) {
 	    rb_raise(rb_eTypeError, "%"PRIsVALUE" does not refer to class/module",
diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index 4ca0e09277..9e9eb13fba 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -338,6 +338,17 @@ class TestModule < Test::Unit::TestCase
     assert_raise(NameError) {self.class.const_defined?(const)}
   end
 
+  def test_nested_defined_inheritance
+    assert_send([Object, :const_defined?, [self.class.name, 'User', 'MIXIN'].join('::')])
+    assert_send([self.class, :const_defined?, 'User::MIXIN'])
+    assert_send([Object, :const_defined?, 'File::SEEK_SET'])
+
+    # const_defined? with `false`
+    assert_not_send([Object, :const_defined?, [self.class.name, 'User', 'MIXIN'].join('::'), false])
+    assert_not_send([self.class, :const_defined?, 'User::MIXIN', false])
+    assert_not_send([Object, :const_defined?, 'File::SEEK_SET', false])
+  end
+
   def test_nested_defined_bad_class
     assert_raise(TypeError) do
       self.class.const_defined?('User::USER::Foo')
diff --git a/version.h b/version.h
index e37c8737f2..e16812c628 100644
--- a/version.h
+++ b/version.h
@@ -1,10 +1,10 @@
 #define RUBY_VERSION "2.6.1"
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 29
+#define RUBY_PATCHLEVEL 30
 
 #define RUBY_RELEASE_YEAR 2019
 #define RUBY_RELEASE_MONTH 1
-#define RUBY_RELEASE_DAY 26
+#define RUBY_RELEASE_DAY 29
 
 #include "ruby/version.h"