[GR-19220] Enable tests for Module#used_refinements (#3097)

PullRequest: truffleruby/3864

Author: eregon

spec/truffleruby.next-specs

@@ -32,3 +32,4 @@ spec/ruby/core/sizedqueue/shift_spec.rb
 
 spec/ruby/core/module/refinements_spec.rb
 spec/ruby/core/refinement/refined_class_spec.rb
+spec/ruby/core/module/used_refinements_spec.rb

src/main/java/org/truffleruby/core/module/ModuleNodes.java

@@ -2210,7 +2210,7 @@ public abstract static class UsedRefinementsNode extends CoreMethodArrayArgument
         protected RubyArray usedRefinements() {
             final Frame frame = getContext().getCallStack().getCallerFrame(FrameAccess.READ_ONLY);
             final DeclarationContext declarationContext = RubyArguments.getDeclarationContext(frame);
-            final Set<RubyModule> refinements = new HashSet<>();
+            final List<RubyModule> refinements = new ArrayList<>();
             for (RubyModule[] refinementModules : declarationContext.getRefinements().values()) {
                 Collections.addAll(refinements, refinementModules);
             }

test/mri/tests/ruby/test_refinement.rb

@@ -1791,13 +1791,17 @@ module RefA
       refine Object do
         def in_ref_a
         end
+
+        RefA.const_set(:REF, self)
       end
     end
 
     module RefB
       refine Object do
         def in_ref_b
         end
+
+        RefB.const_set(:REF, self)
       end
     end
 
@@ -1807,23 +1811,28 @@ module RefC
       refine Object do
         def in_ref_c
         end
+
+        RefC.const_set(:REF, self)
       end
     end
 
     module Foo
       using RefB
       USED_MODS = Module.used_modules
+      USED_REFS = Module.used_refinements
     end
 
     module Bar
       using RefC
       USED_MODS = Module.used_modules
+      USED_REFS = Module.used_refinements
     end
 
     module Combined
       using RefA
       using RefB
       USED_MODS = Module.used_modules
+      USED_REFS = Module.used_refinements
     end
   end
 
@@ -1835,6 +1844,14 @@ def test_used_modules
     assert_equal [ref::RefB, ref::RefA], ref::Combined::USED_MODS
   end
 
+  def test_used_refinements
+    ref = VisibleRefinements
+    assert_equal [], Module.used_refinements
+    assert_equal [ref::RefB::REF], ref::Foo::USED_REFS
+    assert_equal [ref::RefC::REF], ref::Bar::USED_REFS
+    assert_equal [ref::RefB::REF, ref::RefA::REF], ref::Combined::USED_REFS
+  end
+
   def test_refinements
     int_refinement = nil
     str_refinement = nil