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diff --git a/testsuite/tests/typecheck/should_compile/tc091.hs b/testsuite/tests/typecheck/should_compile/tc091.hs
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+-- !!! Test polymorphic recursion
+
+
+-- With polymorphic recursion this one becomes legal
+--	SLPJ June 97.
+
+{-
+To: Lennart Augustsson <augustss@cs.chalmers.se>
+Cc: partain@dcs.gla.ac.uk, John Peterson (Yale) <peterson-john@cs.yale.edu>, 
+    simonpj@dcs.gla.ac.uk
+Subject: Type checking matter
+Date: Fri, 23 Oct 92 15:28:38 +0100
+From: Simon L Peyton Jones <simonpj@dcs.gla.ac.uk>
+
+
+I've looked at the enclosed again.  It seems to me that
+since "s" includes a recursive call to "sort", inside the body
+of "sort", then "sort" is monomorphic, and hence so is "s";
+hence the type signature (which claims full polymorphism) is 
+wrong.
+
+[Lennart says he can't see any free variables inside "s", but there
+is one, namely "sort"!]
+
+Will: one for the should-fail suite?
+
+Simon
+
+
+------- Forwarded Message
+
+
+From: Lennart Augustsson <augustss@cs.chalmers.se>
+To: partain
+Subject: Re: just to show you I'm a nice guy...
+Date: Tue, 26 May 92 17:30:12 +0200
+
+> Here's a fairly simple module from our compiler, which includes what
+> we claim is an illegal type signature (grep ILLEGAL ...).
+> Last time I checked, hbc accepted this module.
+
+Not that I don't believe you, but why is this illegal?
+As far as I can see there are no free variables in the function s,
+which makes me believe that it can typechecked like a top level
+definition.  And for a top level defn the signature should be
+all right.
+
+	-- Lennart
+- ------- End of forwarded message -------
+-}
+module ShouldSucceed where
+
+sort :: Ord a => [a] -> [a]
+sort xs = s xs (length xs)
+   where
+      s :: Ord b => [b] -> Int -> [b]	-- This signature is WRONG
+      s xs k = if k <= 1 then xs
+               else merge (sort ys) (sort zs)
+	       where (ys,zs) = init_last xs (k `div` (2::Int))
+
+-- Defns of merge and init_last are just dummies with the correct types
+merge :: Ord a => [a] -> [a] -> [a]
+merge xs ys = xs
+
+init_last :: [a] -> Int -> ([a],[a])
+init_last a b = (a,a)
+