[project @ 2000-05-31 10:13:57 by lewie]

[ghc-hetmet.git] / ghc / compiler / coreSyn / Subst.lhs

diff --git a/ghc/compiler/coreSyn/Subst.lhs b/ghc/compiler/coreSyn/Subst.lhs
index 62b33c6..1f4c3b8 100644 (file)
--- a/ghc/compiler/coreSyn/Subst.lhs
+++ b/ghc/compiler/coreSyn/Subst.lhs
@@ -35,7 +35,7 @@ import CoreSyn                ( Expr(..), Bind(..), Note(..), CoreExpr, CoreBndr,
                          CoreRules(..), CoreRule(..), 
                          emptyCoreRules, isEmptyCoreRules, seqRules
                        )
-import CoreFVs         ( exprFreeVars )
+import CoreFVs         ( exprFreeVars, mustHaveLocalBinding )
 import TypeRep         ( Type(..), TyNote(..), 
                        )  -- friend
 import Type            ( ThetaType, PredType(..), ClassContext,
@@ -45,7 +45,6 @@ import VarSet
 import VarEnv
 import Var             ( setVarUnique, isId )
 import Id              ( idType, setIdType, idOccInfo, zapFragileIdInfo )
-import Name            ( isLocallyDefined )
 import IdInfo          ( IdInfo, isFragileOccInfo,
                          specInfo, setSpecInfo, 
                          WorkerInfo(..), workerExists, workerInfo, setWorkerInfo, WorkerInfo
@@ -189,7 +188,8 @@ lookupInScope in_scope v
   = case lookupVarEnv in_scope v of
        Just v' | v == v'   -> v'       -- Reached a fixed point
                | otherwise -> lookupInScope in_scope v'
-       Nothing             -> v
+       Nothing             -> WARN( mustHaveLocalBinding v, ppr v )
+                              v
 
 isInScope :: Var -> Subst -> Bool
 isInScope v (Subst in_scope _) = v `elemVarEnv` in_scope