[project @ 2005-07-08 16:16:37 by simonpj]

MERGE TO STABLE (once I"ve checked it works)

The dictionary-floating code in Specialise wasn't taking
variables free in the RULES into account, which resulted in
such variables perhaps going out of scope.

diff --git a/ghc/compiler/specialise/Specialise.lhs b/ghc/compiler/specialise/Specialise.lhs
index 086e7b0..baca12c 100644 (file)
--- a/ghc/compiler/specialise/Specialise.lhs
+++ b/ghc/compiler/specialise/Specialise.lhs
@@ -23,7 +23,7 @@ import VarSet
 import VarEnv
 import CoreSyn
 import CoreUtils       ( applyTypeToArgs, mkPiTypes )
-import CoreFVs         ( exprFreeVars, exprsFreeVars )
+import CoreFVs         ( exprFreeVars, exprsFreeVars, idRuleVars )
 import CoreTidy                ( tidyRules )
 import CoreLint                ( showPass, endPass )
 import Rules           ( addIdSpecialisations, mkLocalRule, lookupRule, emptyRuleBase, rulesOfBinds )
@@ -1050,11 +1050,16 @@ zapCalls ids uds = uds {calls = delListFromFM (calls uds) ids}
 
 mkDB bind = (bind, bind_fvs bind)
 
-bind_fvs (NonRec bndr rhs) = exprFreeVars rhs
+bind_fvs (NonRec bndr rhs) = pair_fvs (bndr,rhs)
 bind_fvs (Rec prs)        = foldl delVarSet rhs_fvs bndrs
                           where
                             bndrs = map fst prs
-                            rhs_fvs = unionVarSets [exprFreeVars rhs | (bndr,rhs) <- prs]
+                            rhs_fvs = unionVarSets (map pair_fvs prs)
+
+pair_fvs (bndr, rhs) = exprFreeVars rhs `unionVarSet` idRuleVars bndr
+       -- Don't forget variables mentioned in the
+       -- rules of the bndr.  C.f. OccAnal.addRuleUsage
+
 
 addDictBind (dict,rhs) uds = uds { dict_binds = mkDB (NonRec dict rhs) `consBag` dict_binds uds }