fix null m_tbl

* class.c (rb_obj_singleton_methods): m_tbl in prepended class/module
  is NULL.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36238 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 10 insertions, 2 deletions

diff --git a/class.c b/class.c
index 537401582a..a642ff0029 100644
--- a/class.c
+++ b/class.c
@@ -1172,12 +1172,14 @@ rb_obj_singleton_methods(int argc, VALUE *argv, VALUE obj)
     klass = CLASS_OF(obj);
     list = st_init_numtable();
     if (klass && FL_TEST(klass, FL_SINGLETON)) {
-	st_foreach(RCLASS_M_TBL(klass), method_entry_i, (st_data_t)list);
+	if (RCLASS_M_TBL(klass))
+	    st_foreach(RCLASS_M_TBL(klass), method_entry_i, (st_data_t)list);
 	klass = RCLASS_SUPER(klass);
     }
     if (RTEST(recur)) {
 	while (klass && (FL_TEST(klass, FL_SINGLETON) || RB_TYPE_P(klass, T_ICLASS))) {
-	    st_foreach(RCLASS_M_TBL(klass), method_entry_i, (st_data_t)list);
+	    if (RCLASS_M_TBL(klass))
+		st_foreach(RCLASS_M_TBL(klass), method_entry_i, (st_data_t)list);
 	    klass = RCLASS_SUPER(klass);
 	}
     }
diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index 7f66911e43..aa48e1793c 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -1284,4 +1284,10 @@ class TestModule < Test::Unit::TestCase
     bug6655 = '[ruby-core:45915]'
     assert_equal(Object.instance_methods, Class.new {prepend Module.new}.instance_methods, bug6655)
   end
+
+  def test_prepend_singleton_methods
+    o = Object.new
+    o.singleton_class.class_eval {prepend Module.new}
+    assert_equal([], o.singleton_methods)
+  end
 end