X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fspecialise%2FSpecConstr.lhs;h=e5583e19dc1181c9e03d46d4bc6521ec473f66f9;hb=2c5337d3f05b1cfb70e2fa63818c453cfc09eb42;hp=78d173140047e3369350d0e540c2e6e3960702e0;hpb=79326edf58637add0e0913189365ccca72c7f82b;p=ghc-hetmet.git

diff --git a/compiler/specialise/SpecConstr.lhs b/compiler/specialise/SpecConstr.lhs
index 78d1731..e5583e1 100644
--- a/compiler/specialise/SpecConstr.lhs
+++ b/compiler/specialise/SpecConstr.lhs
@@ -583,10 +583,7 @@ conArgOccs :: ArgOcc -> AltCon -> [ArgOcc]
 
 conArgOccs (ScrutOcc fm) (DataAlt dc) 
   | Just pat_arg_occs <- lookupUFM fm dc
-  = tyvar_unks ++ pat_arg_occs
-  where
-    tyvar_unks | isVanillaDataCon dc = [UnkOcc | tv <- dataConUnivTyVars dc]
-	       | otherwise	     = []
+  = [UnkOcc | tv <- dataConUnivTyVars dc] ++ pat_arg_occs
 
 conArgOccs other con = repeat UnkOcc
 \end{code}
@@ -878,6 +875,13 @@ argToPat in_scope con_env (Var v) arg_occ
     then return (True, Var v)
     else wildCardPat (idType v)
 
+argToPat in_scope con_env (Let _ arg) arg_occ
+  = argToPat in_scope con_env arg arg_occ
+	-- Look through let expressions
+	-- e.g.		f (let v = rhs in \y -> ...v...)
+	-- Here we can specialise for f (\y -> ...)
+	-- because the rule-matcher will look through the let.
+
 argToPat in_scope con_env arg arg_occ
   | is_value_lam arg
   = return (True, arg)