From 16a642c3315832992b2af401a45b02451c23f165 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Thu, 22 Nov 2018 08:29:02 +0000
Subject: [PATCH] Enable refinements at Object#respond_to?

[Feature #15327] [Fix GH-2020]

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

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65920 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 NEWS                                 |  2 ++
 spec/ruby/core/module/refine_spec.rb | 45 ++++++++++++++++++++--------
 test/ruby/test_refinement.rb         |  4 +--
 vm_method.c                          |  9 +++++-
 4 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/NEWS b/NEWS
index 24bd484cc2..b7a4e8018c 100644
--- a/NEWS
+++ b/NEWS
@@ -20,6 +20,8 @@ sufficient information, see the ChangeLog file or Redmine
 
 * refinements takes place at Kernel#public_send.  [Feature #15326]
 
+* refinements takes place at Kernel#respond_to?.  [Feature #15327]
+
 * +else+ without +rescue+ now causes a syntax error.  [EXPERIMENTAL]
 
 * constant names may start with a non-ASCII capital letter. [Feature #13770]
diff --git a/spec/ruby/core/module/refine_spec.rb b/spec/ruby/core/module/refine_spec.rb
index 97645e5466..3fa493b1da 100644
--- a/spec/ruby/core/module/refine_spec.rb
+++ b/spec/ruby/core/module/refine_spec.rb
@@ -524,21 +524,42 @@ describe "Module#refine" do
       }.should raise_error(NameError, /undefined method `foo'/)
     end
 
-    it "is not honored by Kernel#respond_to?" do
-      klass = Class.new
-      refinement = Module.new do
-        refine klass do
-          def foo; end
+    ruby_version_is "" ... "2.6" do
+      it "is not honored by Kernel#respond_to?" do
+        klass = Class.new
+        refinement = Module.new do
+          refine klass do
+            def foo; end
+          end
         end
-      end
 
-      result = nil
-      Module.new do
-        using refinement
-        result = klass.new.respond_to?(:foo)
-      end
+        result = nil
+        Module.new do
+          using refinement
+          result = klass.new.respond_to?(:foo)
+        end
 
-      result.should == false
+        result.should == false
+      end
+    end
+
+    ruby_version_is "2.6" do
+      it "is honored by Kernel#respond_to?" do
+        klass = Class.new
+        refinement = Module.new do
+          refine klass do
+            def foo; end
+          end
+        end
+
+        result = nil
+        Module.new do
+          using refinement
+          result = klass.new.respond_to?(:foo)
+        end
+
+        result.should == true
+      end
     end
   end
 
diff --git a/test/ruby/test_refinement.rb b/test/ruby/test_refinement.rb
index 11eea720bd..06150d998f 100644
--- a/test/ruby/test_refinement.rb
+++ b/test/ruby/test_refinement.rb
@@ -326,9 +326,9 @@ class TestRefinement < Test::Unit::TestCase
     end
   end
 
-  def test_respond_to_should_not_use_refinements
+  def test_respond_to_should_use_refinements
     assert_equal(false, 1.respond_to?(:foo))
-    assert_equal(false, eval_using(IntegerFooExt, "1.respond_to?(:foo)"))
+    assert_equal(true, eval_using(IntegerFooExt, "1.respond_to?(:foo)"))
   end
 
   module StringCmpExt
diff --git a/vm_method.c b/vm_method.c
index c4f41bc118..0aeac2869e 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -1089,7 +1089,14 @@ rb_export_method(VALUE klass, ID name, rb_method_visibility_t visi)
 int
 rb_method_boundp(VALUE klass, ID id, int ex)
 {
-    const rb_method_entry_t *me = rb_method_entry_without_refinements(klass, id, NULL);
+    const rb_method_entry_t *me;
+
+    if (ex & BOUND_RESPONDS) {
+        me = method_entry_resolve_refinement(klass, id, TRUE, NULL);
+    }
+    else {
+        me = rb_method_entry_without_refinements(klass, id, NULL);
+    }
 
     if (me != 0) {
 	if ((ex & ~BOUND_RESPONDS) &&