[project @ 2001-08-24 12:45:28 by simonpj]

Fix an obscure but easy bug in SpecConstr

diff --git a/ghc/compiler/specialise/SpecConstr.lhs b/ghc/compiler/specialise/SpecConstr.lhs
index 88d32f5..7f2246a 100644 (file)
--- a/ghc/compiler/specialise/SpecConstr.lhs
+++ b/ghc/compiler/specialise/SpecConstr.lhs
@@ -35,6 +35,7 @@ import Util           ( mapAccumL )
 import List            ( nubBy, partition )
 import UniqSupply
 import Outputable
+import UniqFM          ( ufmToList )
 \end{code}
 
 -----------------------------------------------------
@@ -222,6 +223,11 @@ data HowBound = RecFun             -- These are the recursive functions for which
                                -- passed as a parameter and what is in scope at the 
                                -- function definition site
 
+instance Outputable HowBound where
+  ppr RecFun = text "RecFun"
+  ppr RecArg = text "RecArg"
+  ppr Other = text "Other"
+
 lookupScopeEnv env v = lookupVarEnv (scope env) v
 
 extendBndrs env bndrs = env { scope = extendVarEnvList (scope env) [(b,Other) | b <- bndrs] }
@@ -370,18 +376,20 @@ scExpr env e@(App _ _)
 scBind :: ScEnv -> CoreBind -> UniqSM (ScEnv, ScUsage, CoreBind)
 scBind env (Rec [(fn,rhs)])
   | not (null val_bndrs)
-  = scExpr env' body                   `thenUs` \ (usg, body') ->
+  = scExpr env_fn_body body            `thenUs` \ (usg, body') ->
     let
        SCU { calls = calls, occs = occs } = usg
     in
     specialise env fn bndrs body usg   `thenUs` \ (rules, spec_prs) ->
-    returnUs (extendBndrs env bndrs,
+    returnUs (extendBndr env fn,       -- For the body of the letrec, just
+                                       -- extend the env with Other to record 
+                                       -- that it's in scope; no funny RecFun business
              SCU { calls = calls `delVarEnv` fn, occs = occs `delVarEnvList` val_bndrs},
              Rec ((fn `addIdSpecialisations` rules, mkLams bndrs body') : spec_prs))
   where
     (bndrs,body) = collectBinders rhs
     val_bndrs    = filter isId bndrs
-    env'        = extendRecBndr env fn bndrs
+    env_fn_body         = extendRecBndr env fn bndrs
 
 scBind env (Rec prs)
   = mapAndUnzipUs do_one prs   `thenUs` \ (usgs, prs') ->