1 files changed, 50 insertions, 0 deletions
diff --git a/test/ruby/test_compile_prism.rb b/test/ruby/test_compile_prism.rb
index 86f7f0b14f..b95add5bd4 100644
--- a/test/ruby/test_compile_prism.rb
+++ b/test/ruby/test_compile_prism.rb
@@ -2183,6 +2183,56 @@ end
       RUBY
     end
 
+    def test_ForwardingArgumentsNode_instruction_sequence_consistency
+      # Test that both parsers generate identical instruction sequences for forwarding arguments
+      # This prevents regressions like the one fixed in prism_compile.c for PM_FORWARDING_ARGUMENTS_NODE
+
+      # Test case from the bug report: def bar(buz, ...) = foo(buz, ...)
+      source = <<~RUBY
+        def foo(*, &block) = block
+        def bar(buz, ...) = foo(buz, ...)
+      RUBY
+
+      compare_instruction_sequences(source)
+
+      # Test simple forwarding
+      source = <<~RUBY
+        def target(...) = nil
+        def forwarder(...) = target(...)
+      RUBY
+
+      compare_instruction_sequences(source)
+
+      # Test mixed forwarding with regular arguments
+      source = <<~RUBY
+        def target(a, b, c) = [a, b, c]
+        def forwarder(x, ...) = target(x, ...)
+      RUBY
+
+      compare_instruction_sequences(source)
+
+      # Test forwarding with splat
+      source = <<~RUBY
+        def target(a, b, c) = [a, b, c]
+        def forwarder(x, ...); target(*x, ...); end
+      RUBY
+
+      compare_instruction_sequences(source)
+    end
+
+    private
+
+    def compare_instruction_sequences(source)
+      # Get instruction sequences from both parsers
+      parsey_iseq = RubyVM::InstructionSequence.compile_parsey(source)
+      prism_iseq = RubyVM::InstructionSequence.compile_prism(source)
+
+      # Compare instruction sequences
+      assert_equal parsey_iseq.disasm, prism_iseq.disasm
+    end
+
+    public
+
     def test_ForwardingSuperNode
       assert_prism_eval("class Forwarding; def to_s; super; end; end")
       assert_prism_eval("class Forwarding; def eval(code); super { code }; end; end")