[Bug #20392] Block arguments duplication check at `super`

parse.y

@@ -2063,8 +2063,9 @@ get_nd_args(struct parser_params *p, NODE *node)
         return RNODE_FCALL(node)->nd_args;
       case NODE_QCALL:
         return RNODE_QCALL(node)->nd_args;
-      case NODE_VCALL:
       case NODE_SUPER:
+        return RNODE_SUPER(node)->nd_args;
+      case NODE_VCALL:
       case NODE_ZSUPER:
       case NODE_YIELD:
       case NODE_RETURN:

test/ruby/test_syntax.rb

@@ -2154,6 +2154,13 @@ eom
     assert_equal 0...1, exp.call(a: 0)
   end
 
+  def test_argument_forwarding_with_super
+    assert_valid_syntax('def foo(...) super {}; end')
+    assert_valid_syntax('def foo(...) super() {}; end')
+    assert_syntax_error('def foo(...) super(...) {}; end', /both block arg and actual block/)
+    assert_syntax_error('def foo(...) super(1, ...) {}; end', /both block arg and actual block/)
+  end
+
   def test_class_module_Object_ancestors
     assert_separately([], <<-RUBY)
       m = Module.new