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diff --git a/testsuite/tests/typecheck/should_fail/T3323.hs b/testsuite/tests/typecheck/should_fail/T3323.hs
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+-- Trac #3323
+module T3323 where
+
+import GHC.IO.Handle.Types
+import GHC.IO.Handle.Internals
+
+-- The point here is that Handle__ is an existential type, 
+-- so the haDevice field can't be updated.
+--
+-- The bug was that, haDevice is a "naughty" selector, we 
+-- couldn't find its type constructor.  
+-- 
+-- This only happened when you go via an interface file, which is why
+-- this test imports an existential.  To make the test more
+-- standalone, you'd need to make it a two-module test
+
+f :: Handle__ -> Handle__
+f h = h {haDevice=undefined}