X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fmain%2FTidyPgm.lhs;h=fc951cc31d4ceb4e144a3707987808a690182e06;hb=7eb5e29b4a7b6fef55512bc7bf3308e712ca3eba;hp=1f65d212e67aac414c0f64341e31250fc8c683ce;hpb=e517644d3a3272f4306654d0f50db28c664a9a8b;p=ghc-hetmet.git

diff --git a/compiler/main/TidyPgm.lhs b/compiler/main/TidyPgm.lhs
index 1f65d21..fc951cc 100644
--- a/compiler/main/TidyPgm.lhs
+++ b/compiler/main/TidyPgm.lhs
@@ -403,13 +403,14 @@ mustExposeTyCon exports tc
   | isEnumerationTyCon tc	-- For an enumeration, exposing the constructors
   = True			-- won't lead to the need for further exposure
 				-- (This includes data types with no constructors.)
-  | isOpenTyCon tc		-- open type family
+  | isOpenTyCon tc		-- Open type family
   = True
+
   | otherwise			-- Newtype, datatype
   = any exported_con (tyConDataCons tc)
 	-- Expose rep if any datacon or field is exported
 
-  || (isNewTyCon tc && isFFITy (snd (newTyConRep tc)))
+  || (isNewTyCon tc && isFFITy (snd (newTyConRhs tc)))
 	-- Expose the rep for newtypes if the rep is an FFI type.  
 	-- For a very annoying reason.  'Foreign import' is meant to
 	-- be able to look through newtypes transparently, but it
@@ -817,7 +818,7 @@ tidyWorker _tidy_env _show_unfold NoWorker
   = NoWorker
 tidyWorker tidy_env show_unfold (HasWorker work_id wrap_arity) 
   | show_unfold = HasWorker (tidyVarOcc tidy_env work_id) wrap_arity
-  | otherwise   = WARN( True, ppr work_id ) NoWorker
+  | otherwise   = NoWorker
     -- NB: do *not* expose the worker if show_unfold is off,
     --     because that means this thing is a loop breaker or
     --     marked NOINLINE or something like that
@@ -825,8 +826,12 @@ tidyWorker tidy_env show_unfold (HasWorker work_id wrap_arity)
     -- then you can make the simplifier go into an infinite loop, because
     -- in effect the unfolding is exposed.  See Trac #1709
     -- 
-    -- Mind you, it probably should not be w/w'd in the first place; 
-    -- hence the WARN
+    -- You might think that if show_unfold is False, then the thing should
+    -- not be w/w'd in the first place.  But a legitimate reason is this:
+    -- 	  the function returns bottom
+    -- In this case, show_unfold will be false (we don't expose unfoldings
+    -- for bottoming functions), but we might still have a worker/wrapper
+    -- split (see Note [Worker-wrapper for bottoming functions] in WorkWrap.lhs
 \end{code}
 
 %************************************************************************