Fix several bugs related to finding free variables

[ghc-hetmet.git] / compiler / specialise / Specialise.lhs

diff --git a/compiler/specialise/Specialise.lhs b/compiler/specialise/Specialise.lhs
index fa9d253..86fd2fa 100644 (file)
--- a/compiler/specialise/Specialise.lhs
+++ b/compiler/specialise/Specialise.lhs
@@ -23,7 +23,7 @@ import VarSet
 import VarEnv
 import CoreSyn
 import CoreUtils       ( applyTypeToArgs, mkPiTypes )
-import CoreFVs         ( exprFreeVars, exprsFreeVars, idRuleVars )
+import CoreFVs         ( exprFreeVars, exprsFreeVars, idFreeVars )
 import CoreTidy                ( tidyRules )
 import CoreLint                ( showPass, endPass )
 import Rules           ( addIdSpecialisations, mkLocalRule, lookupRule, emptyRuleBase, rulesOfBinds )
@@ -1072,10 +1072,12 @@ bind_fvs (Rec prs)         = foldl delVarSet rhs_fvs bndrs
                             bndrs = map fst prs
                             rhs_fvs = unionVarSets (map pair_fvs prs)
 
-pair_fvs (bndr, rhs) = exprFreeVars rhs `unionVarSet` idRuleVars bndr
+pair_fvs (bndr, rhs) = exprFreeVars rhs `unionVarSet` idFreeVars bndr
        -- Don't forget variables mentioned in the
        -- rules of the bndr.  C.f. OccAnal.addRuleUsage
-
+       -- Also tyvars mentioned in its type; they may not appear in the RHS
+       --      type T a = Int
+       --      x :: T a = 3
 
 addDictBind (dict,rhs) uds = uds { dict_binds = mkDB (NonRec dict rhs) `consBag` dict_binds uds }