UnboundMethod only refer defined_class

UnboundMethod records caller's class, like `D` or `E` on the
following case:

```ruby
class C
  def foo = :foo
end

class D < C
end

class E < C
end

d = D.instance_method(:foo)
e = E.instance_method(:foo)
```

But `d` and `e` only refers `C#foo` so that UnboundMethod doesn't
record `D` or `E`. This behavior changes the following methods:

* `UnboundMethod#inspect` (doesn't show caller's class)
* `UnboundMethod#==` (`d == e` for example)

fix https://bugs.ruby-lang.org/issues/18798

1 files changed, 4 insertions, 4 deletions

diff --git a/test/ruby/test_method.rb b/test/ruby/test_method.rb
index d2c7b6e1dd..a04666890e 100644
--- a/test/ruby/test_method.rb
+++ b/test/ruby/test_method.rb
@@ -1236,12 +1236,12 @@ class TestMethod < Test::Unit::TestCase
     unbound = b.instance_method(:foo)
 
     assert_equal unbound, b.public_instance_method(:foo)
-    assert_equal "#<UnboundMethod: B(A)#foo(arg=...) #{__FILE__}:#{line}>", unbound.inspect
+    assert_equal "#<UnboundMethod: A#foo(arg=...) #{__FILE__}:#{line}>", unbound.inspect
     assert_equal [[:opt, :arg]], unbound.parameters
 
     a.remove_method(:foo)
 
-    assert_equal "#<UnboundMethod: B(A)#foo(arg=...) #{__FILE__}:#{line}>", unbound.inspect
+    assert_equal "#<UnboundMethod: A#foo(arg=...) #{__FILE__}:#{line}>", unbound.inspect
     assert_equal [[:opt, :arg]], unbound.parameters
 
     obj = b.new
@@ -1281,7 +1281,7 @@ class TestMethod < Test::Unit::TestCase
 
     a.remove_method(:foo)
 
-    assert_equal "#<UnboundMethod: B(A)#foo(arg=...) #{__FILE__}:#{line}>", unbound.inspect
+    assert_equal "#<UnboundMethod: A#foo(arg=...) #{__FILE__}:#{line}>", unbound.inspect
     assert_equal [[:opt, :arg]], unbound.parameters
     assert_equal a0_foo, unbound.super_method
 
@@ -1289,7 +1289,7 @@ class TestMethod < Test::Unit::TestCase
     assert_equal 1, unbound.bind_call(obj)
 
     assert_include b.instance_methods(false), :foo
-    assert_equal "#<UnboundMethod: B(A0)#foo(arg1=..., arg2=...) #{__FILE__}:#{line0}>", b.instance_method(:foo).inspect
+    assert_equal "#<UnboundMethod: A0#foo(arg1=..., arg2=...) #{__FILE__}:#{line0}>", b.instance_method(:foo).inspect
   end
 
   def test_zsuper_method_redefined_bind_call