From 77e1363be3a953a8899404cc89e6fa19d0b553c6 Mon Sep 17 00:00:00 2001
From: Peter Arato <it.arato@gmail.com>
Date: Mon, 5 Jun 2023 16:08:41 -0400
Subject: [PATCH] Add Refinement#refined_class

---
 CHANGELOG.md                                       |  1 +
 spec/truffleruby.next-specs                        |  2 ++
 .../org/truffleruby/core/module/ModuleNodes.java   |  9 +++++++++
 src/main/ruby/truffleruby/core/refinement.rb       |  4 ++++
 test/mri/tests/ruby/test_refinement.rb             | 14 ++++++++++++++
 5 files changed, 30 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6973d8b998f5..1d4ed180df4b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ Compatibility:
 * Add `String#bytesplice` (#3039, @itarato).
 * Add `String#byteindex` and `String#byterindex` (#3039, @itarato).
 * Add implementations of `rb_proc_call_with_block`, `rb_proc_call_kw`, `rb_proc_call_with_block_kw` and `rb_funcall_with_block_kw` (#3068, @andrykonchin).
+* Add `Refinement#refined_class` (#3039, @itarato).
 
 Performance:
 
diff --git a/spec/truffleruby.next-specs b/spec/truffleruby.next-specs
index 0f5e3e312239..c9895a6e7064 100644
--- a/spec/truffleruby.next-specs
+++ b/spec/truffleruby.next-specs
@@ -21,3 +21,5 @@ spec/ruby/core/string/bytesplice_spec.rb
 
 spec/ruby/core/string/byteindex_spec.rb
 spec/ruby/core/string/byterindex_spec.rb
+
+spec/ruby/core/refinement/refined_class_spec.rb
diff --git a/src/main/java/org/truffleruby/core/module/ModuleNodes.java b/src/main/java/org/truffleruby/core/module/ModuleNodes.java
index 24d8210ebdd1..b1b86e69c2bd 100644
--- a/src/main/java/org/truffleruby/core/module/ModuleNodes.java
+++ b/src/main/java/org/truffleruby/core/module/ModuleNodes.java
@@ -2584,4 +2584,13 @@ protected Object doClass(RubyClass rubyClass) {
             return rubyClass.isSingleton;
         }
     }
+
+    @Primitive(name = "refined_class")
+    public abstract static class RefinedClassNode extends PrimitiveArrayArgumentsNode {
+
+        @Specialization
+        protected RubyModule refinedClass(RubyModule refinement) {
+            return refinement.fields.getRefinedModule();
+        }
+    }
 }
diff --git a/src/main/ruby/truffleruby/core/refinement.rb b/src/main/ruby/truffleruby/core/refinement.rb
index b32bd43b0d96..d59dfe4d68a2 100644
--- a/src/main/ruby/truffleruby/core/refinement.rb
+++ b/src/main/ruby/truffleruby/core/refinement.rb
@@ -25,4 +25,8 @@ def import_methods(*modules)
     end
     self
   end
+
+  def refined_class
+    Primitive.refined_class(self)
+  end
 end
diff --git a/test/mri/tests/ruby/test_refinement.rb b/test/mri/tests/ruby/test_refinement.rb
index 9a153a0c25b4..6f6c9330b580 100644
--- a/test/mri/tests/ruby/test_refinement.rb
+++ b/test/mri/tests/ruby/test_refinement.rb
@@ -1835,6 +1835,20 @@ def test_used_modules
     assert_equal [ref::RefB, ref::RefA], ref::Combined::USED_MODS
   end
 
+  def test_refined_class
+    refinements = Module.new {
+      refine Integer do
+        int_refinement = self
+      end
+
+      refine String do
+        str_refinement = self
+      end
+    }.refinements
+    assert_equal(Integer, refinements[0].refined_class)
+    assert_equal(String, refinements[1].refined_class)
+  end
+
   def test_warn_setconst_in_refinmenet
     bug10103 = '[ruby-core:64143] [Bug #10103]'
     warnings = [