Remove NOINLINE strictness hack
The stricteness analyser used to have a HACK which ensured that NOINLNE things were not strictness-analysed. The reason was unsafePerformIO. Left to itself, the strictness analyser would discover this strictness for unsafePerformIO: unsafePerformIO: C(U(AV)) But then consider this sub-expression unsafePerformIO (\s -> let r = f x in case writeIORef v r s of (# s1, _ #) -> (# s1, r #) The strictness analyser will now find that r is sure to be eval'd, and may then hoist it out. This makes tests/lib/should_run/memo002 deadlock. Solving this by making all NOINLINE things have no strictness info is overkill. In particular, it's overkill for runST, which is perfectly respectable. Consider f x = runST (return x) This should be strict in x. So the new plan is to define unsafePerformIO using the 'lazy' combinator: unsafePerformIO (IO m) = lazy (case m realWorld# of (# _, r #) -> r) Remember, 'lazy' is a wired-in identity-function Id, of type a->a, which is magically NON-STRICT, and is inlined after strictness analysis. So unsafePerformIO will look non-strict, and that's what we want. Now we don't need the hack in the strictness analyser.