Properly resolve refinements in defined? on method call [Bug #16932]

test/ruby/test_defined.rb

@@ -301,4 +301,32 @@ class TestDefined < Test::Unit::TestCase
   def test_top_level_constant_not_defined
     assert_nil(defined?(TestDefined::Object))
   end
+
+  class RefinedClass
+  end
+
+  module RefiningModule
+    refine RefinedClass do
+      def pub
+      end
+    end
+
+    def self.call_without_using(x = RefinedClass.new)
+      defined?(x.pub)
+    end
+
+    using self
+
+    def self.call_with_using(x = RefinedClass.new)
+      defined?(x.pub)
+    end
+  end
+
+  def test_defined_refined_call_without_using
+    assert(!RefiningModule.call_without_using, "refined public method without using")
+  end
+
+  def test_defined_refined_call_with_using
+    assert(RefiningModule.call_with_using, "refined public method with using")
+  end
 end

vm_insnhelper.c

@@ -3660,7 +3660,7 @@ vm_defined(rb_execution_context_t *ec, rb_control_frame_t *reg_cfp, rb_num_t op_
 	break;
       case DEFINED_METHOD:{
 	VALUE klass = CLASS_OF(v);
-	const rb_method_entry_t *me = rb_method_entry(klass, SYM2ID(obj));
+	const rb_method_entry_t *me = rb_method_entry_with_refinements(klass, SYM2ID(obj), NULL);
 
 	if (me) {
 	    switch (METHOD_ENTRY_VISI(me)) {

vm_method.c

@@ -1088,7 +1088,7 @@ method_entry_resolve_refinement(VALUE klass, ID id, int with_refinement, VALUE *
     return me;
 }
 
-const rb_method_entry_t *
+MJIT_FUNC_EXPORTED const rb_method_entry_t *
 rb_method_entry_with_refinements(VALUE klass, ID id, VALUE *defined_class_ptr)
 {
     return method_entry_resolve_refinement(klass, id, TRUE, defined_class_ptr);