diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 5742251004..9b6a8d7dea 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -424,7 +424,7 @@ void rb_exec_end_proc(void);
 void rb_thread_schedule(void);
 void rb_thread_wait_fd(int);
 int rb_thread_fd_writable(int);
-DEPRECATED(void rb_thread_fd_close(int));
+void rb_thread_fd_close(int);
 int rb_thread_alone(void);
 void rb_thread_sleep(int);
 void rb_thread_sleep_forever(void);
diff --git a/thread.c b/thread.c
index 736946bf68..7a902d2751 100644
--- a/thread.c
+++ b/thread.c
@@ -2197,15 +2197,10 @@ rb_notify_fd_close(int fd)
     return busy;
 }
 
-NORETURN(void rb_thread_fd_close(int fd));
 void
 rb_thread_fd_close(int fd)
 {
-#ifdef DONT_USE
     while (rb_notify_fd_close(fd));
-#else
-    DEPRECATED_INTERNAL_FEATURE("rb_thread_fd_close");
-#endif
 }
 
 /*