X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fspecialise%2FSpecConstr.lhs;h=5357a5353958c0b094ca3928e11985082ac2849e;hp=3dfda94ca3bc91fe442458ebaa28b407fb750fe4;hb=703ca1542c8e0983cc9d8eebce6e9f3dd3fd71e2;hpb=120c4c72d6b12e765da9e69612351a53fb7cef4b

diff --git a/compiler/specialise/SpecConstr.lhs b/compiler/specialise/SpecConstr.lhs
index 3dfda94..5357a53 100644
--- a/compiler/specialise/SpecConstr.lhs
+++ b/compiler/specialise/SpecConstr.lhs
@@ -27,11 +27,11 @@ import Coercion
 import Rules
 import Type		hiding( substTy )
 import Id
+import MkId		( mkImpossibleExpr )
 import Var
 import VarEnv
 import VarSet
 import Name
-import OccName		( mkSpecOcc )
 import DynFlags		( DynFlags(..) )
 import StaticFlags	( opt_PprStyle_Debug )
 import StaticFlags	( opt_SpecInlineJoinPoints )
@@ -778,7 +778,8 @@ scExpr' env (Case scrut b ty alts)
   where
     sc_con_app con args scrut' 	-- Known constructor; simplify
 	= do { let (_, bs, rhs) = findAlt con alts
-		   alt_env' = extendScSubstList env ((b,scrut') : bs `zip` trimConArgs con args)
+	       	   	          `orElse` (DEFAULT, [], mkImpossibleExpr (coreAltsType alts))
+		   alt_env'  = extendScSubstList env ((b,scrut') : bs `zip` trimConArgs con args)
 	     ; scExpr alt_env' rhs }
 				
     sc_vanilla scrut_usg scrut'	-- Normal case