Thread.pass always return nil

core/thread.rbs

@@ -1015,7 +1015,7 @@ class Thread < Object
   # Give the thread scheduler a hint to pass execution to another thread. A
   # running thread may or may not switch, it depends on OS and processor.
   #
-  def self.pass: () -> untyped
+  def self.pass: () -> nil
 
   # <!--
   #   rdoc-file=thread.c

test/stdlib/Thread_test.rb

@@ -65,6 +65,10 @@ def test_each_caller_location
   def test_list
     assert_send_type "() -> Array[Thread]", Thread, :list
   end
+
+  def test_pass
+    assert_send_type "() -> nil", Thread, :pass
+  end
 end
 
 class ThreadTest < Test::Unit::TestCase