Fix {Method,UnboundMethod}#{public?,private?,protected?} for ZSUPER methods

Add a visibility member to struct METHOD storing the original
method visibility, and use that, instead of taking the visibility
from the stored method entry (which may have different visibility
for ZSUPER methods).

Consider Method/UnboundMethod objects different if they have
different visibilities.

Fixes [Bug #18435]

proc.c

@@ -40,6 +40,7 @@ struct METHOD {
     const VALUE iclass;
     const rb_method_entry_t * const me;
     /* for bound methods, `me' should be rb_callable_method_entry_t * */
+    rb_method_visibility_t visibility;
 };
 
 VALUE rb_cUnboundMethod;
@@ -1626,6 +1627,7 @@ mnew_missing(VALUE klass, VALUE obj, ID id, VALUE mclass)
     me = rb_method_entry_create(id, klass, METHOD_VISI_UNDEF, def);
 
     RB_OBJ_WRITE(method, &data->me, me);
+    data->visibility = METHOD_ENTRY_VISI(me);
 
     return method;
 }
@@ -1683,6 +1685,7 @@ mnew_internal(const rb_method_entry_t *me, VALUE klass, VALUE iclass,
     RB_OBJ_WRITE(method, &data->klass, klass);
     RB_OBJ_WRITE(method, &data->iclass, iclass);
     RB_OBJ_WRITE(method, &data->me, me);
+    data->visibility = visi;
 
     return method;
 }
@@ -1780,6 +1783,7 @@ method_eq(VALUE method, VALUE other)
 
     if (!rb_method_entry_eq(m1->me, m2->me) ||
 	klass1 != klass2 ||
+        m1->visibility != m2->visibility ||
 	m1->klass != m2->klass ||
 	m1->recv != m2->recv) {
 	return Qfalse;
@@ -1833,6 +1837,7 @@ method_unbind(VALUE obj)
     RB_OBJ_WRITE(method, &data->klass, orig->klass);
     RB_OBJ_WRITE(method, &data->iclass, orig->iclass);
     RB_OBJ_WRITE(method, &data->me, rb_method_entry_clone(orig->me));
+    data->visibility = orig->visibility;
 
     return method;
 }
@@ -2340,6 +2345,7 @@ method_clone(VALUE self)
     RB_OBJ_WRITE(clone, &data->klass, orig->klass);
     RB_OBJ_WRITE(clone, &data->iclass, orig->iclass);
     RB_OBJ_WRITE(clone, &data->me, rb_method_entry_clone(orig->me));
+    data->visibility = orig->visibility;
     return clone;
 }
 
@@ -2590,6 +2596,7 @@ umethod_bind(VALUE method, VALUE recv)
     RB_OBJ_WRITE(method, &bound->klass, klass);
     RB_OBJ_WRITE(method, &bound->iclass, iclass);
     RB_OBJ_WRITE(method, &bound->me, me);
+    bound->visibility = data->visibility;
 
     return method;
 }
@@ -2625,7 +2632,7 @@ umethod_bind_call(int argc, VALUE *argv, VALUE method)
         VALUE methclass, klass, iclass;
         const rb_method_entry_t *me;
         convert_umethod_to_method_components(data, recv, &methclass, &klass, &iclass, &me);
-        struct METHOD bound = { recv, klass, 0, me };
+        struct METHOD bound = { recv, klass, 0, me, METHOD_ENTRY_VISI(me) };
 
         return call_method_data(ec, &bound, argc, argv, passed_procval, RB_PASS_CALLED_KEYWORDS);
     }
@@ -3314,7 +3321,7 @@ method_public_p(VALUE method)
 {
     const struct METHOD *data;
     TypedData_Get_Struct(method, struct METHOD, &method_data_type, data);
-    return RBOOL(METHOD_ENTRY_VISI(data->me) == METHOD_VISI_PUBLIC);
+    return RBOOL(data->visibility == METHOD_VISI_PUBLIC);
 }
 
 /*
@@ -3329,7 +3336,7 @@ method_protected_p(VALUE method)
 {
     const struct METHOD *data;
     TypedData_Get_Struct(method, struct METHOD, &method_data_type, data);
-    return RBOOL(METHOD_ENTRY_VISI(data->me) == METHOD_VISI_PROTECTED);
+    return RBOOL(data->visibility == METHOD_VISI_PROTECTED);
 }
 
 /*
@@ -3344,7 +3351,7 @@ method_private_p(VALUE method)
 {
     const struct METHOD *data;
     TypedData_Get_Struct(method, struct METHOD, &method_data_type, data);
-    return RBOOL(METHOD_ENTRY_VISI(data->me) == METHOD_VISI_PRIVATE);
+    return RBOOL(data->visibility == METHOD_VISI_PRIVATE);
 }
 
 /*

test/ruby/test_method.rb

@@ -199,6 +199,11 @@ class TestMethod < Test::Unit::TestCase
     assert_equal(o.method(:foo), o.method(:foo))
     assert_equal(o.method(:foo), o.method(:bar))
     assert_not_equal(o.method(:foo), o.method(:baz))
+
+    class << o
+      private :bar
+    end
+    assert_not_equal(o.method(:foo), o.method(:bar))
   end
 
   def test_hash
@@ -1200,6 +1205,31 @@ class TestMethod < Test::Unit::TestCase
     assert_equal(false, Visibility.instance_method(:mv1).protected?)
   end
 
+  class VisibilitySub < Visibility
+    protected :mv1
+    public :mv2
+    private :mv3
+  end
+
+  def test_method_visibility_predicates_with_subclass_visbility_change
+    v = VisibilitySub.new
+    assert_equal(false, v.method(:mv1).public?)
+    assert_equal(false, v.method(:mv2).private?)
+    assert_equal(false, v.method(:mv3).protected?)
+    assert_equal(true, v.method(:mv2).public?)
+    assert_equal(true, v.method(:mv3).private?)
+    assert_equal(true, v.method(:mv1).protected?)
+  end
+
+  def test_unbound_method_visibility_predicates_with_subclass_visbility_change
+    assert_equal(false, VisibilitySub.instance_method(:mv1).public?)
+    assert_equal(false, VisibilitySub.instance_method(:mv2).private?)
+    assert_equal(false, VisibilitySub.instance_method(:mv3).protected?)
+    assert_equal(true, VisibilitySub.instance_method(:mv2).public?)
+    assert_equal(true, VisibilitySub.instance_method(:mv3).private?)
+    assert_equal(true, VisibilitySub.instance_method(:mv1).protected?)
+  end
+
   def rest_parameter(*rest)
     rest
   end