Was that last line supposed to be "readIORef x" instead of "pure x"? If you return the IORef then the result is equivalent to "newIORef 1", not "pure 1"—and new

Was that last line supposed to be "readIORef x" instead of "pure x"? If you return the IORef then the result is equivalent to "newIORef 1", not "pure 1"—and newIORef does have observable side-effects. (Two IORefs are distinct even if they hold the same value.)